Thoughts of adding strakes

[CharlieN]

Background,
This winter I intend to flip my 20' Glastron in order to refinish the bottom. Over the years it has accumulated many chips and developed blisters where it sites on the bunks.
A chip or two are letting water migrate into the hull which has been structurally rebuilt.
This boat is a straight V hull with 18 or 19° rise with 4 full length strakes. I have removed the hook or at least most all I could from the center portion of the running surface. This will be checked once the hull is flipped onto a cradle.
When I bought the boat it ran 47mph and with the work I have done it tops out at 62 now.
The engine will be receiving an Excel powerhead so if anything next year will again be a quicker runner.

My question,
I have been giving thought to adding a pair of strakes inboard of what is there. The existing inner strakes are 26 apart on their outer face.
What I do not have a feel for is what differences in handling, ride and performance would one expect from the added lift?
I am expecting a performance gain such as a pad offers but I do not have enough experience running different hulls to know what to expect.

I do not have an image of the bottom so this view from the back might be what I have now,
http://users.vermontel.net/~dcma/Boat/JupS1.jpg

[tunnels]

DONT ADD MORE STRAKES JUST INCREASE THE WIDTH OF WHAT THERE ON THE 2 OUTER ONES
Double there width or even go to 2 and half times as wide , make then from wood and resin coat and screw in place to trial them and see if that's where your headed . don't increase the width any more than 6 to 8 feet forward of the transom as that's about how much of the hull length is carrying the hull weight at speed ! and if you go to far forward then makes a hard riding hull
Me I like wide strakes and there stability they offer rather than a ski plank down the middle so the hull falls one side or the other and end up chine walking !!

[CharlieN]

Outer ones, Interesting, my mind was on inner. Your thoughts will provide a very stable base and yes I do not want to build a narrow tricky to drive platform, nor a hard riding one.

The one bit of information I am missing on my boat are good pictures of how the hull rides at speed. I do not know if it is lifting above the outer strakes now or riding on them.
And this leads to how much hull is used when running 10 to 15 faster than it runs now.

[CptBeav]

I've had similar thoughts of extending my inner chines to the stern as GT hulls have them ending about 2ft before the transom. I would imagine full length inner chines on our hulls would be the closest to a pad without having a true pad.

My hull rides right where the inner chines end
306087


Maybe it could cause more violent chine walk as the hull starts riding higher on the vee and ruducing the wetted surface on the added strakes???

[CharlieN]

A few years back I read about the inners on the 150 being extended back. To me that is logical in that it will give more lift further back which will flatten the hull at speed. The flatter hull should be more stable.

[Da Bull]

Nothing works as well as a center pad. Glastron made a few 20ft Mod-VP boats way back in the early 80`s with a pad. The boats were very stable.
BTW, Make sure you change the tuner to one made for the Excel when you install the powerhead.

DB

[XstreamVking]

Bottom is good, just add some more power......If anything widen all the existing strakes so the balance is still there. Remember though, the more wetted area, the more drag you must overcome. Once again, more HP needed.

[CharlieN]

Nothing works as well as a center pad. Glastron made a few 20ft Mod-VP boats way back in the early 80`s with a pad. The boats were very stable.
BTW, Make sure you change the tuner to one made for the Excel when you install the powerhead.

DB

I look at the few pictures of the blue mod Vp boat longing for it to come to market. But I am sure that when it does I would not be able to fund it at the time.

I have the tuner sitting here, My desire was to get it in under my existing powerhead for this past season to see if the restrictive tuner is what caps the rpm to 5100. But last winter the engine stayed on the boat rather than being stored in the shop so I never got the chance to pull it apart.

[CharlieN]

Bottom is good, just add some more power......If anything widen all the existing strakes so the balance is still there. Remember though, the more wetted area, the more drag you must overcome. Once again, more HP needed.

I expect the Excel powerhead will be offering about 40 hp. My next step will be to port the 150 to the Excel configuration with finger ports added.

[CVX20SPRINT]

Bottom is good, just add some more power......If anything widen all the existing strakes so the balance is still there. Remember though, the more wetted area, the more drag you must overcome. Once again, more HP needed.

Didn't think you could hang enough power off of the back of one of these to get it out of the water.Don't get me wrong I love mine,but it just doesn't strike me as a real fast hull.Great ride though.

[CharlieN]

It defiantly is not what one would consider a fast hull, after all it is just a ski boat. But I think with a bit more lift it could be "almost fast"
I just do not want to loose the good characteristics such as the ride.

[XstreamVking]

Going from a 150 to a 250+ hp motor should make it a diff boat. 60 mph w/150 hp is good as it is now. Same boat with 250 XS would perform well.

[CharlieN]

My 150 has the 34mm carbs and horizontal reeds. The porting is the same as a 1990 200 which is claimed to put out 210ish. Since I have the restrictive tuner still I expect that keeps me capped well less than that.
The Excel will be quite noticeable from this level especially where the proper tuner will let it spin up a bunch more.
Part of me says to just clean up the bottom and not modify it at this time. But then that part of me that modifies most everything.
This thread is good for the thought patterns.

[stokernick]

My uneducated opinion would be to make a pad, but it does take some ability to drive it on the pad! Less boat in the water, time to fly!!

[CharlieN]

I have some more information for my project, This afternoon I got a chance to get on the water with a friend being able to snap some pics.
These two pics are of the boat running the high side of 61mph, all she wants to do at this time.

http://users.vermontel.net/~dcma/Boat/CVX14/Echo60.jpg

http://users.vermontel.net/~dcma/Boat/CVX14/Echo61.jpg
Clearly no point in working above the inner strakes which the hull is planted on.
Critique?

[XstreamVking]

Boat wants more bottom rocker. Or more weight to the rear.

[CharlieN]

The fuel tank is in the bow and has about 15 gal on board. When I rebuilt the hull I made space for a 20 gallon tank under the floor in the last 40" of hull. I just have get around to welding up the tank.

At that time I worked all the hook out between the inner strakes, out at the chine it has hook but that does not affect this.
Possible there is a touch of hook and this will be addressed this winter.
But you are thinking adding some rocker.

I have 8" setback and for the most part I am running a 25P Predator that is nice and sharp. It does not like to be run high and trimming up is non responsive. Clearly that prop can not pick this hull up.

So your thoughts are on rocker rather than overall lifting surface to loosen the hull up.

[CharlieN]

My uneducated opinion would be to make a pad, but it does take some ability to drive it on the pad! Less boat in the water, time to fly!!
I keep rolling my thoughts on building a pad.
This hull has a protruding keel under the forward 2/3 of the boat, part of what made them one of the better ski boats back then.
A few years back when the core was being rebuilt I gave thought to filling the bottom of the V and glassing it over in prep of flipping the hull and cutting in as needed for a pad.
At this time the hull is fully foamed in so digging in to do any structural work inside the hull is not desired.
This is where my thoughts have been on strakes, obviously if strakes are added right near the centerline they would effectively be a pad.
If added out a little ways would add lift with a wider running surface, better for some of my friends that also run the boat who would not have the finesse to balance the boat on the pad.
I will be out under the hull later this morning measuring if the running surface is flat or not. This will be important and will not have a final assessment till the hull if turned over and on the work cradle.

[XstreamVking]

Try a 24/26p chopper if you can. It will drop the stern, lift the bow. Lets you run the motor higher and trim up some. Get all the weight out of the bow. Boat ride attitude is level, motor is level. Running up on the strakes like it is designed to do. Just needs tuning. For what it is, performance is good now.

[CharlieN]

For the chopper, I presume the larger ear version?
I see a fair bit of talk about the Tempest. One just went on ebay that I considered grabbing. Only reason I did not was that I want to swap powerheads before prop testing.

[XstreamVking]

I like the tempest props. Good bow lift. I have one for my stream for running with 2/3 passengers or going in choppy salt water areas. Good all around prop. A chopper, big or small will surprise you with the change in the boats bow lift at speed.

[CharlieN]

Just checked with a 4' straightedge, looks to be .090" hook with the downturn in the last 8" or so up near the inner strakes. The port side is a little less, call it .060-.070.
Down along the keel is straight for about a 10" width.
I did not check in front of that to if or what curve is forwards of this.

[CharlieN]

I like the tempest props. Good bow lift. I have one for my stream for running with 2/3 passengers or going in choppy salt water areas. Good all around prop. A chopper, big or small will surprise you with the change in the boats bow lift at speed.
It will be nice to get a prop that responds well. The Predator has a nice cruise but cavitates easily. Highest I can run the motor is about 3½" below. This is with stock case still. Seems happiest about 4" down.
Part of me wants to buy a prop now since I will be running about 60 miles on the Ct river run a month from now. The other part of me has been saying to wait till the power has been added.

[CharlieN]

I like the tempest props. Good bow lift. I have one for my stream for running with 2/3 passengers or going in choppy salt water areas. Good all around prop. A chopper, big or small will surprise you with the change in the boats bow lift at speed.
What are your thoughts between a 3 blade or 4 blade Chopper?

[XstreamVking]

Never ran a 4 blade chopper style prop. No help there.....3 blade big or small choppers can be surfaced and will give tons of bow lift. Only boat I run a 4 blade on, is my flats boat. It's a predator 25p with xtra cup and works really well for low and mid range not very good for top end , gets right on the limiter. Top end w/predator=70. Top end with 3 blade 27p tempest 78 mph. Same r's on top, just slower to plane with tempest vs predator. Same flats boat with a labbed 28p lightning ET is 83mph, at 5850 r's.. IMO re-prop after power increase.

[CharlieN]

I did just purchase a 3 blade Chopper that has some leading edge nicks on it. There is a nice looking 4 blade out there as well.
I will freshen the 3 blade and run it and see how it runs.
I have wanted a 4 blade and have a Composite 23 pitch that is impressive out of the hole. This is what I run in stump and rock infested waters. I also just tried a 4 blade 25P shooter, I am thinking the hub is spinning in it, the prop is horrible. At 4K the predator is running over 50, the shooter was 42 at best. I would occasionally get a vibration and the boat would slow down. I never opened the throttle in a 10 mile run last weekend with it.

[Jimboat]

This winter I intend to flip my 20' Glastron in order to refinish the bottom...When I bought the boat it ran 47mph and with the work I have done it tops out at 62 now. My question, I have been giving thought to adding a pair of strakes inboard of what is there. The existing inner strakes are 26 apart on their outer face. What I do not have a feel for is what differences in handling, ride and performance would one expect from the added lift?
Charlie - cool project!
If your desired purpose for mods is to increase speed, then increasing lift on centerline of the hull can help you. Inner-located strakes will help accomplish more lift, but remember that the bigger you make the strakes, the more exposed edge there will be as a trip hazard. Of course, the need for additional speed will come with different handling characteristics, particularly in turning, and a rougher ride. it's always a compromise.


I keep rolling my thoughts on building a pad.
I think that you're right that inner-located strakes are very similar to a pad. you might find that a center pad could add some desired lift, and might do so with a lesser exposed trip edge. Here's an article (http://www.screamandfly.com/content.php?219-The-Bottom-Line-How-a-Pad-Makes-a-Vee-Hull-Faster) on pad desgin and performance that might be of interest.


This afternoon I got a chance to get on the water with a friend being able to snap some pics. These two pics are of the boat running the high side of 61mph, all she wants to do at this time.
From your pictures, it appears that there is quite a bit of boat in the water at the speed taken (the outer strakes are wetted at the aftmost locations). If that is top speed, then you might benefit from a prop that generates a bit more bow lift and perhaps move some weight to lighten your bow. The long wetted length of the hull with this setup is adding substantial drag that reduces top speed.

Sounds like a fun project!

[Tinkerer]

I had a 1977 CVX 18 that had a pad bottom and was very stable even in the rough.
My fuel tank was in the bow also - move as much weight to the back as you can. Get that tank out of the bow.
If you want to modify it add a pad.
OH and it did mid 90's



307158

[CharlieN]

Jim, thank you for looking this over and your thoughts, I do not have a desire for wide strakes, if I add strakes they will be equal or narrower than what exists. Call it similar to a 7" wide pad. At this point if I add a pad it would be just that, added. I do not have the desire to remove the new floor, foam and center stringer to do glass work from the inside. I have access to the aft 40" of centerline but in front of that would be complex.
So this would present me that either the pad or strakes would give similar trip edge.
My boat gets driven buy people that I am sure would not concentrate on driving at high speeds which leads my thoughts that the wider base of strakes would be a easier to drive although somewhat less performance potential than a pad.

One other thing my thoughts are on is notching the transom. I have 8" setback now I presume that acts to add more setback?
I see thoughts of the notch when researching the 21' hulls.

I will have a Chopper prop here on Tuesday, probably just as the rain arrives but I will run it soon as I can to see if it can lift this hull.

Tinkerer, looks like you had that 18 running right well. Out of curiosity about how much power did you have in it?
My next project will probably be a 21' car powered boat which will start out with an LS motor in the mid 300 but can climb easily from there.

On this hull I am installing a 20ish gallon tank under the aft floor that will be in addition to the front tank. This way the front tank can be left empty till the range is needed.
When I rebuilt the structure I located the battery, oil tank and jack pump port side just behind the rear seat, these could be moved back 3' feet or so. Other than lighter front seats there is no easy to move weight.
The boat at this time is 390# lighter than when I bought it.

[Jimboat]

Charlie, what does your boat weigh?

[CharlieN]

Charlie, what does your boat weigh?
1630 with oil and battery.
The center of gravity is 51" forward of transom.

[Aaronhl]

The 1984 Glastron CVX17 pad bottom is maybe a hull design you want to check out. We have one and can do 45mph with two people and 75hp

[Jimboat]

1630 with oil and battery.
The center of gravity is 51" forward of transom.
With your current power and light weight hull, you're right around the top speed that I would expect - perhaps just a couple mph more maximum. Not sure a pad would help you too much.

[CharlieN]

With your current power and light weight hull, you're right around the top speed that I would expect - perhaps just a couple mph more maximum. Not sure a pad would help you too much.

Interesting,
Come spring this will have an Excel on the back so an estimate of close to 240Hp is what I will be working with.

[Jimboat]

That kind of HP will make a big difference to something!

[Tinkerer]

Ford 302 CI - boss 302 block and crank. Aluminum aftermarket Jim Valakeo ported heads, 12 to 1 ratio pistons, solid roller cam, high rise intake and throttle body fuel injection. MSD ignition, Custom one off through transom headers.
engine raised 3 inches and Alpha SS drive. Still had the gas tank in front. That was going to be the next project. Then sold the boat when I bought the Checkmate 251.

[CharlieN]

So 370 to 425ish power? With the drive setup what was your propline below hull, 3½ish? I am thinking I will be starting with a 5.3 aluminum LS engine, the small bore since they hold up better with a supercharger. I will first run NA though. I was thinking a hybrid Bravo SSM5 drive but I doubt I will come up with a SSM5 lower I can afford. So possibly a shortened Bravo upper with SSM3 lower. Hull will either be a CVX20 Deluxe converted to sterndrive from the jet or one of George Linders 21s.

I intend to start collecting parts this winter but I need to finish my current boat first. One thing I did when I rebuilt the structure in this hull is to eliminate the aft 4' of center stringer, call it much as the car motor versions would be thus allowing for the fuel tank below floor.

[Da Bull]

Excel powerhead, Pad, cut in step, good prop and more setback should do it. One more thing to think about. Gear ratio. You either have 1.87-1 or 2.0-1 as both came on the 150hp models. The Excel came with 1.80-1 so if you keep the 150 gears you need to be thinking about larger pitch props.
Question: Is the Excel powerhead complete with the correct carbs and heads?

DB

[XstreamVking]

If you are gonna stuff the ls very hard, I would think a steel truck block would be more reliable for the build. I know it's heavier, but they are a lot stronger.

[CharlieN]

Excel powerhead, Pad, cut in step, good prop and more setback should do it. One more thing to think about. Gear ratio. You either have 1.87-1 or 2.0-1 as both came on the 150hp models. The Excel came with 1.80-1 so if you keep the 150 gears you need to be thinking about larger pitch props.
Question: Is the Excel powerhead complete with the correct carbs and heads?

DB
The Excel powerhead is complete, I have two sets of 34 carbs and Excel heads. My 150 did not have the original 2.0 gears, it has a somewhat salty lower with 1.87. Eventually I want a fresher lower, an Excel unit would be nice.
My current 150 has 34 carbs on a ported horizontal front with CCR reeds, bearing webs are stuffed.
I have the controller for the Excel minus coils. Not sure which ignition to run for lake use with 91 oct non Ethanol.
I currently am using an 8" setback lift, this can easily be changed.

My engine now just pulls 5100 rpm with 23 and 25 pitch props, this is with the restrictive 150 ProV tuner so I expect there is room for the Excel to rev with what props I have to start with at least. When I change the tuner I will be restricting some water flow in the mid.

[CharlieN]

If you are gonna stuff the ls very hard, I would think a steel truck block would be more reliable for the build. I know it's heavier, but they are a lot stronger.
The LS I intend would be in the 550ish range which my local guy says is fine with the small bore block. I have allot to learn still with these.

[Da Bull]

At 5100rpm your far of from what a stock Excel will do. I raced with two of them on two different style boats and both liked the 6700rpm range with anywhere from a 28 to a 32p prop. We had the rev limiter disconnected but other than that they were all stock.

[CharlieN]

I expect the restrictive tuner is holding this engine back but I have read of other ProV that have reved higher, It will be interesting to see both what the Excel will offer as well as getting the hull to run freer.
The chopper prop will be in my hands mid day Monday, I am looking forward to seeing what it offers and finally seeing how things react to raising the engine since the Predator does not like running high.

[CharlieN]

Chopper prop with weed cutters is mounted up and waiting for a test run.

[CharlieN]

I made my first test with the Chopper, this is an A5 26p. It does not run as fast as the 25p Predator I have been running at cruise or top speed, the Predator tops at 61.8 @5100 revs loaded or running light. The Chopper I was seeing 55 ish, the GPS shown 57 at one short point, I was seeing what may have been 5200 revs. Raising the engine would get an rpm rise without speed increase similar with trim. It did not blow out but when raise to the point the prop was above the hull bottom it was all I could do to hold the steering. Defiantly ways from where the skeg is adjusted.
Nice thing I really like is the prop holds in corners, this was the first time I have had this hull cornering at 1G+, the predator would not let the hull corner better than .7G. Being a sports car guy that is lazy.
The photos my wife got shows the hull running flat with more water kicked up depending what trim or drive height I was running.

So next is to rework the bottom of the hull over the winter. Before that I have a 50+ mile river run coming up and not truly sure which prop I will run.

[CharlieN]

Now that spring has sprung up here in Vermont it seems only a month or two ago we had some snow,
http://users.vermontel.net/~dcma/Boat/CVX15/Cover%20snow.jpg
But now most of the snow is gone and it is time to start playing with boats again, so I figure it is time to get to the bottom of this.
So I dragged my hull out behind the shop where few ever go and flipped it over.

http://users.vermontel.net/~dcma/Boat/CVX15/Flipped1b.jpg

http://users.vermontel.net/~dcma/Boat/CVX15/Flipped1c.jpg

http://users.vermontel.net/~dcma/Boat/CVX15/Flipped2.jpg

http://users.vermontel.net/~dcma/Boat/CVX15/Flipped4.jpg

http://users.vermontel.net/~dcma/Boat/CVX15/Flipped4b.jpg
Now I can really get to the bottom of this.

[concord18]

Get my cvx 17 back this week from extending my strikes and blue printing the bottom. Moved my tank to the back, added core where there was none, new stringers, transom, styrofoam floor, rigging starts, ugh, but yea! I'll post pis tomorrow. Putting a 225 super mag on her, 6" notch! plus 8" jack plate, should see 90!

[CharlieN]

That should be serious fun.
I spent some time yesterday sanding the last 6" or so of the hull getting the hook out. This did take off a light downturn, the hook that was there.
What I have now is between the keel and inner strakes is about a 0.090 depression on one side and less on the other in aft 4' of the hull that needs filling.
Had this been a cored hull or epoxy this would probably been straight still.
The nice thing I find is where I did all the structural work a few years back the strakes are straight as can be.

This hull has plenty of chips and blisters to be dealt with as well as getting proper repair where someone sent drywall screws through the hull when the "new floor" was installed.

Then of course the main subject of this thread, adding some lift which looks like that will be installing a pad.

[CharlieN]

On the subject of moving weight back, when I rebuilt the core a few years back I made it so I can install a 22 gallon fuel tank under the aft floor. It has the 27 Gal bow tank but once I weld up the aft tank this will offer me options for fuel load. This pic is from 3 years ago.
http://users.vermontel.net/~dcma/Boat/Tankwell.jpg

[CharlieN]

I am getting a chance to work on the bottom, in mocking up a core for the pad I find an interesting trait that I am not sure if is an issue or not. With the sun coming out today, something that only happens a few days a month here I can not get a good pic of this.

With the pad built so it's edges are parallel to the keel center the stern of the pad will be lower than the strakes in a side view. This would make the pad have an angle of attack slightly greater than the factory strakes are. Call it less than 3/8 over 8'.
If I splay the rear of the pad a few inches it will be parallel in height to the strakes.

My question would be, would the pad having a greater angle of attack be more of an issue over a slight delta shape?
Core splayed,
http://users.vermontel.net/~dcma/Boat/CVX15/PadCore1.jpg

Attempt to show non parallel,
http://users.vermontel.net/~dcma/Boat/CVX15/PadSide.jpg

[whipper]

I would loose the entire centre Strake. Thats only there to help keep the hull from getting pulled buy a skier. Its not helping you get any high pressure air under the hull to help with lift at any speed. It will deflect and cause turbulence disrupting high pressure effects at speed. Your angle of attach is to low and the air flowing over your deck is to high of pressure. you need to get the hull UP at a good angle of attack for better pressure differentials. After deep sixing the center stake add a pad as mentioned. The aft 4 feet should do. Im in a hurry but something like this. the side profile is that sketch off on the side. This will create lift at the steer and give you a better angle of attack. Your motor looks buried also. The prop shaft hight raised will also help achieve a better angle of attack. Just a thought. Most fast Vee bottoms dont have that centre stake and the vee is a little more rounded not so sharp and have a pad. Engine hights vary from 1/4 below to above the pad prop shaft hights. http://i63.photobucket.com/albums/h151/whipperr/PadCore1_zpsrev2qvet.jpg (http://s63.photobucket.com/user/whipperr/media/PadCore1_zpsrev2qvet.jpg.html)

[CharlieN]

I keep looking at the protruding keel wishing I had addressed that when I was doing the structure inside. But giving thought to it there is not any reason I could not remove it with all the glass work from the outside. The center stringer sets down into that keel and may well provide a surface to form the glass on.

i do have good access to the last 5' of the center of the hull on the inside so setting a pad in is possible.

[CharlieN]

On engine height, that has been dictated by the prop I have run, an old 25p Predator that does not like to be jacked up. The jack on this boat will lift the propshaft a few inches above the keel so I have the ability to tune.
I did a brief test with a 26p Chopper which was an easy 5mph slower through all rpm ranges but it sure gripped better.

[whipper]

Hears a more streamlined profile of the bottom that wouldn't take much to get like. maybe some grinding off and see how far ya can go? Im thinking the strake on the bottom off and rounded with material added in the stern for a pad or to just get the lines straighter from the keel so there's not the whale forward area. If you check out a Charger bottom something like that? The keel is sharp on the stern and has no lift built into it. Most sterns have some kind of flatter area at the stern like in this pic. The red line of your hull is what i see as faster bottom without getting all crazy with steps ect.. Yours looks to be a 16 deg bottom? with some straighter lines should be pretty fast with as mentioned power. But the way the bow is deeper than the stern is whats really keeping you wet. it takes way to much lift to get that out of the water. So Thats why i would try and remove it if faster is what your after. http://i63.photobucket.com/albums/h151/whipperr/Flipped4_zps6tcwdnfe.jpg (http://s63.photobucket.com/user/whipperr/media/Flipped4_zps6tcwdnfe.jpg.html) http://i63.photobucket.com/albums/h151/whipperr/DSC_0668.jpg (http://s63.photobucket.com/user/whipperr/media/DSC_0668.jpg.html) http://i63.photobucket.com/albums/h151/whipperr/pics175-1.jpg (http://s63.photobucket.com/user/whipperr/media/pics175-1.jpg.html)

[whipper]

25 trophy or 26 Drag4 or talk to Todd at Hydromotive enganering he can get you hooked up and with speed. With your hulls weight a 4 blade might be the way to go. if you get more lift into the hull coupled with a great lifting prop you start to have a good recipe to create some aerodynamic lift under the hull with less hydrodynamic drag equals speed. OR buy an Allison with a 280.:D Most aired out shots of fast hulls you will see under the hull the stern is deeper than the bow wear it breaks. Your hull is lower at the stern. The more you can change that the faster you will be. What will change is the driving at above 65-70. once you can get to those speeds and higher balancing the hull threw driver input becomes critical to over come the hulls tendency to chine walk. No big deal as all Vee hulls will at faster speeds. it just takes some practice to drive her on the back of the hull at 70+.:thumbsup:

[whipper]

Hears a couple pics of a Viper bottom. This would be a good way to go also adding a delta pad. Just widen the wood you have for your strake pic and fill in the center. Then you could add less at the bow to get less vee hanging in the forward section of the keel if that makes sense. http://i63.photobucket.com/albums/h151/whipperr/ViperBottom2_zpsawfeqzna.jpg (http://s63.photobucket.com/user/whipperr/media/ViperBottom2_zpsawfeqzna.jpg.html) http://i63.photobucket.com/albums/h151/whipperr/ViperBottom9_zpsjsotrzzu.jpg (http://s63.photobucket.com/user/whipperr/media/ViperBottom9_zpsjsotrzzu.jpg.html)

[CharlieN]

I just bought a 25 Trophy, this will be my third 4 blade, One previous one acts like it is spinning the hub and the other at 23P gets out of the hole great but is just too short.
This hull has a 19° rise.
Just got back in from staring at my hull, I am leaning towards cutting off the protruding keel and adding the pad from there back. The pad will end up about 8" wide, details of that will obviously change as I progress and this project develops further.
I am reluctant on cutting a delta pad into the hull due to my work time being limited. I think I am safer adding the pad to the existing structure.

[CharlieN]

I like the pad style on the Viper, mine to start with would not have the strakes right next to the pad.
This hull has a fairly pronounced whale up front, this reflexes up to the vee. It looks like the pad may blend nicely into the back side of the whale. I have no clue how the get contrast of this area so it shows up in pictures. Probably once the keel is blended it may show.

[CharlieN]

No pictures yet but I have started to remove the keel. More tomorrow.

[whipper]

That sounds like a good plan. That {Whale} is the biggest issue. its just hanging so far down the running surface it never gets aired out. so much drag having the whole hull in the water like that at speed. If you look at the air under the side shot of mine you can see were you need to head. Gota get that bottom in front out of the water some how to get less wetted surface. More setback might be something to try before you get the motor back on? It will help with the candle leaver effect and move your centre of ballance farther back. That will help free up the bow also at speed. Sounds like a fun project. You should get some more speed out her taking that deep keel strake off. My hull is fairly rounded all the way back on the keel line and is 950 lbs. It handles the chop nice and smooth. i looked for an Allison GS bottom pic but couldnt find one. i put that stern pic as reference to the width of the pad on mine for reference.

[CharlieN]

I had to head out for work for a bit, I think building the pad the way I have started it will offer enough lift up front that may get the whale to release. Last year when I was getting pics of the boat running there was nothing I could do to get lifted off the chines. The hull has nearly no hook and getting a good look at the underside today I am really thinking the shape of the bow is really holding itself down. Absolutely great for a ski boat, Flat and smooth. I am looking forward to these changes to see how the hull responds.
I am planning more setback, it will be a bit later on though. Kind of one step at a time although I am doing hull and some motor at this venture.

[CharlieN]

So here we go, Is the first cut the deepest?
http://users.vermontel.net/~dcma/Boat/CVX15/Keelcut1.jpg

Here I have started removing the keel,
http://users.vermontel.net/~dcma/Boat/CVX15/Keelcut2.jpg

I did find the stringer to be wet, something I have feared since after rebuilding the structure and not refinishing the outside I was finding that water was coming in from somewhere. I still do not know where but it was getting into the foamed in area under the floor.
Luckily it has been sunny and actually hot here the past few days so I have let the sun at the hull allowing the moisture out.
Today with not detecting any more moisture It is time to move forwards again.
I have mixed a slurry of resin, loose and runny at first then a drier Microballoon mix that I will later grind into.
http://users.vermontel.net/~dcma/Boat/CVX15/KeelFill1.jpg

http://users.vermontel.net/~dcma/Boat/CVX15/KeelFill2.jpg

http://users.vermontel.net/~dcma/Boat/CVX15/KeelFill3.jpg
The way I am approaching this since I am forced to work from the outside only is to prep, grind and layup two sections, then cut out the last of the keel and finish the layup. This way the hull remains stable during this work.
http://users.vermontel.net/~dcma/Boat/CVX15/KeelFill4.jpg
Later on I will finish rough shaping the wood core for the pad, bond these in place, final shape them then glass them.

[Aaronhl]

OK now you have my attention...keep us updated...

[FMP]

This is interesting, the end result will be faster higher riding hull. Cool . How are the blackflies?

[CharlieN]

No flies here yet, last of our snow is just melting away the past few days.
It will be interesting just how much this work will offer performance wise. Should be a fair amount since these hulls were designed to stick to the water part, of being a good ski boat and not a performance hull.

[CharlieN]

I thought I would be laying up glass today till I realized I am out of release film, Oh well next week I start. If it were not for the multiple layups involved I would be going for it.

[FMP]

:mad:Just got on the water, first time this year. Very thick rotten lake ice still floating around , flies just starting.

[CharlieN]

Prep work is making headway today, I am prepping to fill cracks and blisters. Here is some stress cracking up front from when the boat was run with rotten structure, there is a fair bit of this.
http://users.vermontel.net/~dcma/Boat/CVX15/Stress.jpg

Here is the other side that I have ground the cracks out of the gelcoat.
http://users.vermontel.net/~dcma/Boat/CVX15/CrackGrind3.jpg

Back near the stern some cracks ground out and the hook sanded off,
http://users.vermontel.net/~dcma/Boat/CVX15/CrackGrind1.jpg

Some more blisters that had cracks running between them,
http://users.vermontel.net/~dcma/Boat/CVX15/BlistersGrind.jpg

And on the transom some drilled holes and cracks, I had filled the holes with 4000 sealant but now to do a better job.
http://users.vermontel.net/~dcma/Boat/CVX15/CrackGrind2.jpg

And for me, the big win, I found the water leak, I think. Till I was grinding on this the passage was not apparent.
http://users.vermontel.net/~dcma/Boat/CVX15/Hole.jpg
I will be grinding this a bit further before filling but it will be rewarding to not have water coming in when the boat is tied up overnight.

[CharlieN]

The weather is letting me work on this again although it was below freezing this morning. I have finished prepping for the first layups along the keel. With luck this afternoon I will be able to cut and prep the last short section so tomorrow I can get further on glass work before the next rains come.
http://users.vermontel.net/~dcma/Boat/CVX15/KeelFill5.jpg

I have also filled the edges of the strakes and rough sanded them, these should be nice and sharp when done.
http://users.vermontel.net/~dcma/Boat/CVX15/Strake1.jpg

[CharlieN]

Frustrations today, It was cold most all morning which was fine for suiting up for grinding but it delayed me from starting layups. But once the fabric was cut all seemed good. Well until I was doing the second section of laying in two plys of 1700 when I noticed the release fabric was wrinkling up.
http://users.vermontel.net/~dcma/Boat/CVX15/KeelFill6.jpg
Damn, not a big thing but it compromises the simplicity for when I am laying in the next 6 plys.
Anyways I cut off the last section of keel and filled under the stringer. It is late enough that this will not be ready to grind today so I am not as far along as I hoped. I have ordered in 10 more yards of the peel ply I have been working with for the last 33 years, I should have stayed with what I am used to instead of buying new stuff that cost less. Material cost should not direct a project.
But here is the last section filled,
http://users.vermontel.net/~dcma/Boat/CVX15/KeelFill71.jpg

And a view from the side with no keel anymore,
http://users.vermontel.net/~dcma/Boat/CVX15/Keelcut3.jpg
By eye you can now really see the whale in the front of the running surface.My eyes do not see it in the picture here. Next week I will be shaping the core for the pad to blend into this.

[CharlieN]

Another frosty morning, not sure how quick I will get going on this today.

[olboatman]

Great stuff Charlie!:thumbsup: Thanks for taking the time to share your project with us. Right up my ally since I have been wantin to add a pad to my MFG skiff one of these winters. Keep up the good work! ;)Gary

[CharlieN]

Thank you Gary, Your MFG should not be all that difficult to add a pad to. If I recall they are essentially a flat bottom with a steep Vee in the center and the two outer chines. Guess they are not chines when the project downward. Looks like it would be the surface prep, selecting and shaping the core then going for it. Probably would be an interesting boat to drive.

[olboatman]

Thank you Gary, Your MFG should not be all that difficult to add a pad to. If I recall they are essentially a flat bottom with a steep Vee in the center and the two outer chines. Guess they are not chines when the project downward. Looks like it would be the surface prep, selecting and shaping the core then going for it. Probably would be an interesting boat to drive.

Your recall is right on! The boat is already a handfull with my modded 25 (boat weights 140lbs and was rated for 10hp!) and was designed to be a cartopper! I have already braced the transom and the gunnels(to stop the flappin) and I thought the pad would take her to the next level. Gary

[CharlieN]

The pad will get the flat bottom off the water, should make a big difference. I wonder if it would be more stable with smaller pads on the outer Vees to reduce the chance of digging in. One step at a time though. Been a long time since I have been in one of them.

[CharlieN]

Today started out frosty again but I got out there and did a session of grinding, got my fabric cut and commenced to laying up 8 plys. When closing out I sure wish I had cut some release film even if this stuff does not work well with VE resin. Still is better than working open fibers. Oh well, I do have 10 yards of peel ply on the way. But I am done for the day.
http://users.vermontel.net/~dcma/Boat/CVX15/KeelFill9.jpg
Next step will be fitting and shaping the core for the pad. Maybe by mid week I can be building that step.

[CharlieN]

I got a good step done today. With some final prep I got the pad cores bonded in place and started the final shaping of them.Here are the wood cores set in place.
http://users.vermontel.net/~dcma/Boat/CVX15/PadCore2.jpg

This shot has the cores bonded in place, I used screws through the hull as well as weight to hold them. It took me some time to accept using screws but they allowed me accurate and repeatable placement.
http://users.vermontel.net/~dcma/Boat/CVX15/PadCore3.jpg

The back of them is cut to allow the fiberglass to bond to the bottom of the hull,
http://users.vermontel.net/~dcma/Boat/CVX15/PadCore4.jpg

And then the filler pieces will be bonded in place which will need minimal glasswork over them.
http://users.vermontel.net/~dcma/Boat/CVX15/PadCore5.jpg

At the front end I am using a Microballon blend to build up the shape. This is just the first application. This gives me a more durable structure should the skin get breached, this reduces the chance for water to get in the core.
http://users.vermontel.net/~dcma/Boat/CVX15/PadCore6.jpg

I did start final shaping of the cores but did not have my camera at hand so those pics later.

[olboatman]

Lookin good Charlie. I was wondering if you were gonna leave some setback at the end of the pad..... looks like you answered my question. Gary

[CharlieN]

I am thinking the pad is going right to the transom but my approach allows for it to be short. I just have not made that decision yet and today might be when that needs to be decided.

[CharlieN]

Well, My CVX-20 Sprint now has a PadVee hull. It has been a long day, I still need to clean up but that will be after dinner.
http://users.vermontel.net/~dcma/Boat/CVX15/Pad2.jpg

http://users.vermontel.net/~dcma/Boat/CVX15/Pad1.jpg

http://users.vermontel.net/~dcma/Boat/CVX15/Pad3.jpg

http://users.vermontel.net/~dcma/Boat/CVX15/Pad4.jpg
Tomorrow, Friday I am taking a day off and my wife and I are going for a flight in a B-17. I need a day away.
Saturday I will be back to this. I will pull some of the peel ply. Shape the small bits of core at the stern and hopefully glass that area. I will also build a new transom water pickup since the previous one is no longer suitable.
There is some detail filling that needs to be done but unfortunately I might have to quit the work on this and get the hull upright and start reassembling the boat. For me time and materials are running out.

[olboatman]

Keep it up Bro your almost there!!!:thumbsup: Great work ....wish I had time to do some modden to my rigs but business is way too busy. :(:DGary

[CharlieN]

I am feeling the time crunch of customer deadlines looming. I have a big vintage car race meet late in the year which will eat most of my summer getting work done for.
As much as I want to finish this properly I will soon run the boat and get a baseline on handling and performance. I am hoping to get the shape of the reworked area as close as I can but I have run myself low on VE resin, I expect I have enough to mix a bunch of filler there are other areas I wanted to do glass work such as the underside of where the engine well was removed. Nice to get that done while the hull is upside down. By the time I restock this boat needs to float.
All trough this project I have been wishing I could mount this hull on my rotisserie but the way the hull extends aft of the structural transom make that impractical. At least my Superboat will have the benefit of the rotisserie when that hull gets worked on.

[FMP]

:thumbsup:Wow , that's almost getting done. I didn't think you would do a full length pad , that will work well. I thought a delta pad,maybe 5 feet from the stern.

[CharlieN]

This pad should be better all around. Ultimate top speed is not my goal, wrong boat for that. But good rough water and moderately good speed is what I want.

[FMP]

Sure, that will work very well. I think the speed may surprise.

[CharlieN]

I am hoping or call it expecting that to be so. I have a bit more power now as well.

[CVX20SPRINT]

Nice work,but I think my old slow CVX20 will have to stay slow before I tear into something like that.

[CharlieN]

Chris, If the pad was done without removing the keel it would not be a bad job. The rough shaping of the wood core was not time consuming. I really wish I had chosen to infuse the core layup but I did not have a thin VE resin and had no intention to do this in the MAS epoxy.
Need to see just how this performs to see what the value really is.

[CharlieN]

Frustration today, This morning was below freezing so it was not an early start. Once I was working on this I got my prep work done, mixed my first batch of filler, got that spread, going for my next batch and discovered the bottom two inches of resin in the gallon can is jelly. Seal was broken on this can just last week. WTF?
There is no way I can get more resin here with the holiday since I only had three more days to make my goal.
Well my work is about 80% done, I knew I could not make it to 100% but I expected to get the fairing done.
Oh well, rest of today and tomorrow will be final sanding on what I can and the boat goes upright to be rigged.

[mackeral5]

What's the latest on this cool project? Adding a pad, going from a ProV 150 to an excel, very interesting to say the least!!!!!

[CharlieN]

Humm a week has snuck by since I updated, The boat is back on the trailer as of last weekend, I have welded up a new transom pickup which entailed some final shaping of the last few inches of the pad. I then hung the engine and started with rigging. I am making a number of changes such as the trim relays are in the hull now. This requires a sealtite fitting trough the hull and a complete rewire of the limit switches for the jack-trim system which when I powered the boat up a day ago it appears I got the NO and NC sides of the limit switches reversed. Back under the aft deck to redo that.
With the boat being upside down for weeks I did not get away without needing to bleed the steering. During this winter I had machined new swivel bushings since it is common to have some play, no more now. This motor has a stainless tiller arm and a few years back I had the bolt holding the steering cylinder seize up buggering the threads. So my repair there was to change to a ½" bolt. That required machining new bushings for the steering cylinder.
Yesterday's task was a road trip to the warehouse to collect a new Dexter Vcamber axle and springs. I then slid the boat off into my pond for the afternoon while I changed out the running gear under the trailer. What a treat when one lives with a bad shoulder.

With the boat sitting in water for a half day, it still gets some water in the bilge. WTF does it take to have a fully dry hull?

I still have a pretty long list to do before the Romp, such as machining a new instrument panel and well seeing about firing up this new to me Excel. That is a rather high priority at this point.

[CharlieN]

Latest update, I was up at the Romp at Great Sacanadaga lake with the boat and due to time crunch I had not properly tested the new to me motor before traveling. Turns out there is a glitch in the ignition and the engine would not rev past 3k. So at this point I have learned nothing from my work.
Once the engine makes power this should be a happier story.

[olboatman]

Keep right at it Charlie.......you will get it!!!!;) Gary

[CharlieN]

After some diagnostic work I replaced the Throttle sensor and the engine at least tries but is far from right. It is probably up to 100 Hp or so, the boat will lazily get up to 40.
The one thing I noticed is the work I did on the hull, low speed obviously, this thing corners great now. I think it may be real nice to learn how it feels once I can get up to speed.
Charlie

[CharlieN]

I now have the motor running strong. It had corrosion in some terminals in the new to me main harness.
Now I can begin my learning and tuning.

[FMP]

So is it still a work in progress? Would like to hear that it really got it out of the water.

[CharlieN]

So is it still a work in progress? Would like to hear that it really got it out of the water.
Humm has been some time since I have updated this. Back in July when I thought I had the motor up to full power, well not fully, for some reason It stops pulling just over 5K. It has considerably more mid range power now but then just falls flat. My one chance I had to get a real test in was almost "good"
Yes the hull was starting to air out, from around 50mph it is feeling considerably lighter than ever. Photos my wife shot show the bow riding higher than ever, which for this old ski boat is not very high still. Around 5K rpm I think the power was falling below what the original 150 ProV was giving me. I was seeing 65MPh, just a few more than the 62 I was seeing before the work. The hull at that point was starting to get dancy so I would say it was just starting to climb on the pad.
This outing was followed with me going into surgery for shoulder reconstruction which has been a much needed blessing for me and the end of the last decade of misery I have lived under. Needless to say I have not done anything else with the boat since early August.
I am not sure what spring will bring for me time wise to work with this. Since my surgery word has gotten out in the road race world that I have use of my arm again and I am now swamped with work, 4 cars to build for next season. Being I no longer have employees as a one man show this is allot of work. I do not think I will have time to play with my own toys till June or July at the best. At least I have a chance of refilling the long empty bank account.

Back on my boat I am wondering if I am overlooking something like the fuel pumps restricting my top end power since the powerhead and tuner change should allow the engine to spin up at least 1K more than it has been especially with the hull now lightening up.

[FMP]

Good to hear the shoulder is on the mend. THe hull mods work and all you need is the power back to air it out.

[CharlieN]

Good to hear the shoulder is on the mend. The hull mods work and all you need is the power back to air it out.
Not to mention learn to drive it. It will take me some time to get comfortable with running on the pad. I only touched on this my last time out that running at speed in some chop I expect it was climbing up and started some chine walk, nothing big but I was not ready to go there.
I sure wish there was a dyno nearby so I can learn what the engine is trying to tell me. I feel like I am back in the dark ages without getting data from the engine. I keep coming home from the lake with questions, not answers. This Yamaha Excel technically has data available But I have no way to access it.

[olboatman]

Charlie Glad to hear you are gettin ready to give the world hell again!!! I know where you have been and are goin thru due to my knees and my surgery. Back to your boat.... You said that the Excel has data available and have no way to access it . Does that mean that there is a program you need for a laptop? If so maybe there is a member on here that could help? Just thinkin outloud as nothing is as bad as knowin something is wrong and not being able to "put a finger on it" . Keep on it as you will work it out and we are here to help!!! Gary

[CharlieN]

After my shoulder was responding far better than average and learning we have a new to the area foot surgeon. I went to her to see what she could offer with a rather old injury. The issue is way up inside the foot and is non operable. Oh well. Now onto the knees.

The Excel data uses a special harness that looks to plug into the oil system. Just offers blinking light type code. Appears that outside a dealer this info is unknown. I have no dealers anywhere around me.
By the mid 90s actual trouble codes were available from these systems.
These remind me of the old Bosch inspection steps, move throttle 7 times, tap brake pedal then read a meter. Different procedure for different devices. You had to be a master tech with all the training to know that stuff.

[XstreamVking]

Didn't those things have a crude o2 sensor? If so that could make it go rich.....And kill your hp.

[CharlieN]

The O2 sensor came in later. These had a knock sensor which had it's own issues but I do not think is what I am troubled with. But then I can not be sure. This Excel sure is strong in midrange compared to the modded 150. But they both stop pulling around 5K. I figured that was due to the restrictive tuner the ProV ran. But the Excel is setup the way it belongs with the proper tuner so I did not expect the power to fall off as it does. I expected it to pull to the limiter as many say it will. The only thing non stock in the powerhead is this has a milled exhaust plate. The idea is sound but this leaves a generous step on the roof of the exhaust ports close to the cylinder. I have a stock plate ready to go on but back a few months ago I could not raise my right up arm to change it. Now that I am getting decent use of the arm it is supposed to be winter up here, I do look at the boat most every day. Just can not play with it.

Fuel delivery is haunting me though. Same pumps off the old motor. I intend to at least test with an electric pump.
This hull has a front tank so the pumps are pulling through a pretty long straw. It is rigged for a rear tank, I just have not built the tank yet.

[W2F a V-King]

It does sound like fuel delivery, seeing as how you have similar rpm limitations with two different power heads on the same fuel system.
Guessing the fuel lines and connectors are all minimum 3/8" ID, and no kinks or restriction?

I had a 1987 Excell 225 I bought new for a CC North American I had. It was a great motor, ran strong...just couldn't keep pistons in it. That was the years when Yamaha had soft pistons and started knocking the wrist pin bosses out of the pistons. Happened twice under warranty. The final warranty repair they used weisco pistons and problem solved!

Great work on the pad! :thumbsup:

James

[Aa Hayes]

Sorry to dig up an old thread, but very interesting! What happened?

[CharlieN]

Sorry to dig up an old thread, but very interesting! What happened?

Over the summer of 2015 I lost most all use of my right arm, surgery late in the year did me real well. Spring of 2016 my business took off again and to date I have not even pulled the winter cover off my boats. I look at them wishing but just have not done anything.

I have bought an electric fuel pump to install near the tank with expectations that may be the engines power limitation. Then I can get back to developing the hull. But for the time being I am stuck in the shop with more work than I can keep up with.

[Aa Hayes]

Over the summer of 2015 I lost most all use of my right arm, surgery late in the year did me real well. Spring of 2016 my business took off again and to date I have not even pulled the winter cover off my boats. I look at them wishing but just have not done anything.

I have bought an electric fuel pump to install near the tank with expectations that may be the engines power limitation. Then I can get back to developing the hull. But for the time being I am stuck in the shop with more work than I can keep up with.

I thank you kindly for the update, and I wish you all the best in all your adventures.

[FMP]

Good to hear things are improving. I was thinking about this thread lately.

[CharlieN]

It is clear I have not been here in years. My should issue seemed good right after surgery. Issue that persisted is if I try to pull on a wrench or bend over to lift anything the shoulder dislocates forwards. Turns out part of the surgery was removing 70% of my AC tendon. I did not place much thought to that but what remains was stretched out allowing instability. In late 2019 I thew in the towel on trying to be productive and trying to keep my business going. Since backing my workload down the shoulder only now is becoming stable. Still can not sit back or lay on my back cause the should will not allow that pressure, Oh well. So for me, my mid 60s arrived and I let SS start feeding the bank.
Update on my boat.
Early 2020 I uncovered this boat and launched it on my pond. I had never properly pickled it a half a decade ago. Turns out it was not hurt by that. Not that I can tell at least. I had only clipped on an EarthX jump pack. The Excel was kind of tight turning, I had pulled the plugs and sprayed some oil in each cyl. I fired it on a hose and then to the pond we went. It felt good to just motor about. The pond was low, not common for the spring so I did not have much room. It was nice though. I trailered it, vacuumed all the flotation foam bits the mice had spread about and put it away again. It was happy and sad but I look forward to what this year will offer for actually getting on the water. Time to make changes to the fuel system to see if fuel restriction is the engines limiter or what I am up against. I am also thing I want to make changes to the pad I had built and add a step providing more lift and a wider surface to balance on. I can not plan much of a work load since I have designed another airplane and am build that. Got to keep the mind active.