12' Cat Build

[Hoffer]

A few pictures of my Cat project.
LOA. 12'
Beam. 5.5'
Power. 60 hp plus? Outboard.427749427750427751427751427752427753

[largecar91]

Welcome to the site. Looks like a cool little project. It looks stout. What are you estimating the weight to be? Also how deep a tunnel and what kind of lift?

[Hoffer]

Thanks, it is sturdy. As it sits in the pictures its 170 lbs....ish, trying for 400 lbs or less. The tunnel is 2.5' wide, height tapers down rearward very slightly to 6"

[Will hedrick]

Looks great bud welcome to s and f,

[idvette]

Where in Ontario are you?

[Hoffer]

Mt. Albert, North of Toronto .
My buddy's cottage is on Big Cedar lake in the Kawarthas, probably where I will test this thing .......eventuality.

[idvette]

Nice. There's a bunch of performance boating enthusiasts in the Kawarthas. We usually get together a few times a year for runs on different lakes and rivers, would be cool to see that little tunnel run! What motor are you thinking, 3 cylinder?

[FMP]

Hoffer, great project! Are they your plans?

ID,
Didn't you guys do a calendar with your boats?

[Hoffer]

Nice. I'm not sure about the motor, its being built to hold more than it should. My original plan was to buy a used boat on a trailer, motor etc to keep cost down at first. The boat is a complete experiment for me at this point, it should easily hold 50 to 100 pls up. I'm going to need a manual jack plate with minimal set back and everything else as the time comes. Its a work in progress and things change every time I look at it. If you have spare parts you want to sell defiantly let me know.

[Hoffer]

Yes they are my plans.....actually way more time in the design than the build at this point. All going to plan so far.

[FMP]

Awesome! Don't listen to me, I'll talk you into a CHRYSLER triple!

[Hoffer]

No problem with Chrysler. ........ If the boat would hold it I'd throw the 6.7 Cummins out of my truck in it.
I'm open to whatever as long as it pushes this thing.

[idvette]

Fast Boats Canada have been doing calendars for years now, HPBC did them for a year or two as well. Hoffer, have a look at OPBRA's website next month as we update our race classes, we are going over class rules as we speak for a 3 cylinder class.

[oldschoolltv]

Subscribed!

[FMP]

Fast Boats, that's what I thought.

Nothing like good triple, 72ci, 224lbs . You think it'll hold that weight?

[Hoffer]

Will do, thanks. My uncle was a Canadian national champ in grand prix hydros late 80's early 90's. I myself think you boat racers are crazy, I raced superbikes instead. Retired 10 years ago and now boat project to fill the void. Got hooked when I bought 21 super boat.....way to big and fast for Big Cedar lake. And I blew up the 225 merc, my bad.
sorry.....went off on a tangent. Tends to happin while I'm sitting in the garage....with bee, while looking at bikes and a boat I should be working on.
I am up for suggestions on what I should hang off the back of it though .

[Hoffer]

Nice boat, thanks for checking out what I'm doing.

[Hoffer]

Oh yah. That's light compared to what I have been looking at.

[Hoffer]

FMP. If its light and makes good power? It is designed for 20" shaft.....No motor well.

[W2F a V-King]

How much weight are you thinking you can hold?

Cool project for sure !!

[FMP]

That's a 20" weight. 78 later , better lower. I know a couple folks who run them. Bill Edwards brother runs a built 90 on a 15' kneeldown @ 70-75 mph, he's 350lbs, not sure what the boat weighs.
Anyway just shooting the breeze, looks good.

[Hoffer]

Transom is 2 1/4" thick reinforced top and bottom. Should be good for 300 plus pounds.

[W2F a V-King]

Hmmmm .... good candidate for an XS1500...thinking they weigh a bit under that w/pt.

But at 12' long she's gonna set nose way up....No?

[Hoffer]

I'm shooting for 400 lbs ish. Plan is for nicer cockpit, left hand drive with controls in center console. Stereo etc.

[Hoffer]

Hull is fairly deep and wide for 12', center of gravity should be mid cockpit.

[Hoffer]

The plan is to have the boat run flat ish, like the big cats on the back 3rd of the hull. Not so much flying it like conventional tunnels. If the boat works properly it shouldn't need a lot,if any positive trim.....depending on set up.

[home made tunnel]

The plan is to have the boat run flat ish, like the big cats on the back 3rd of the hull. Not so much flying it like conventional tunnels. If the boat works properly it shouldn't need a lot,if any positive trim.....depending on set up.

Mine 13.5' tunnel runs pretty flat - But I have a pair of 6" wide planning pads for the last 6' of the hull, with a 370 pound motor, and a jack plate. Gas tank in back too. Do you have any pictures of your steps on the bottom of the hull?

I have a freshly rebuilt and restored 90hp Chrysler/Force triple you could throw on yours. Typical mercury wiring/controls/ignition are on it. I took off the 90 and went to a 120 for my red boat in my signature. The 90 is the one on it in that picture. (Black mercury lower and mid, White cowl, Chrysler/force powerhead).

[Hoffer]

I am planning on flipping it soon so I have no real pictures of the bottom of the hull. The back 3rd of the sponsons are an 8 degree angle so all most flat, 2 stepped sections start just after centre rearward. The sponsons will be skinned in sections, while the bow angle will need some creative woodworking/fiberglass to arrive at the shape I'm trying to achieve. The sides are fairly flat and straight forward as is the deck, should be fairly straight forward to cover. The cockpit sides, windshield, dash and centre console will go in last and contour to the deck.
As far as power, I'm still not sure. Your Chrysler looks like it would work well on this boat.
Did you glass over your boat or just the seams?
what did you use to paint the frame..inner structure?

[home made tunnel]

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The entire boat is encapsulated in fiberglass cloth and resin. There is no exposed wood anywhere. The paint I used was wet-edge top-side paint from Jamestown Distributors. Paint was used on the top side, and inside.

The bottom and hull sides is 100% covered in gelcoat.
First, it was all covered in cloth and epoxy. Next, I did a couple coats of Gel coat high-build epoxy primer. Then I sprayed white Gel coat over the top, and did a LOT of wet sanding / cutting and buffing / polishing. If I were to do it again, I would have never used gelcoat on the outside and stuck with just the Wet-Edge primer on the whole boat.
Another learning point was after I coated everything with epoxy/fiberglass, I would always have to do a second coat with epoxy to fill the weave of the fiberglass, or sand the weave down smooth. I learned of a product after I was done with the boat called Peel-Ply. Essentially it's fancy plastic wrap that you squeegee onto wet epoxy like window tint, and peel it off when the epoxy dries (like wax paper), and you get a reeeeally smooth coverage with minimal sanding afterwards.

I also attached a couple pics of the 90hp motor I put back together. Used it maybe less than 6 hours after the rebuild before I found a 120hp local and swapped onto my red boat.

[Hoffer]

Thanks for all the information, every time I see pictures of your build it gives me more to think about.
I notice you don't have many or any battens, you had mentioned in your thread your boat is all 1/2".
My bulkheads are 3/4" and I want to skin it with 1/4", I haven't bought the wood yet as I'm still on the fence about it.
As well I am testing some out side the box finishes for the hull.
Nice motor, would probably work really well on this boat.

[home made tunnel]

My bulkheads are 3/4" and I want to skin it with 1/4",

Nice motor, would probably work really well on this boat.

1/4" may be too thin, especially on flat surfaces. As soon as you give plywood a curve, it becomes MUCH stronger though. My front deck that has a curve, and the rear hatch behind the seat are like STUPID strong. No flex. But the tunnel bottom being flat under my feet flexes a bit when I stuff the tunnel. Nothing to concern me at all, but I can tell its bottoming out sometimes in rough water, or when going slow and it slaps, I can feel it flex.
But yes, mine was 100% 1/2" plywood. African Okume mahogany marine ply. Bought from Boulter Marine in Massachusets.

If you're interested in the 90hp I have, send me a private message.

[Hoffer]

I have some 1/2" as I was going that route originally, if I can find some help I will flip it this weekend and get the tunnel bottom skinned with 1/2". just worried about the bend at the nose,if it wont go maybe double 1/4" up front. As it sits the boat is very solid, that being said I will get a better feel when it comes off the jig.
Maybe a little less thinking and more working now.

[Hoffer]

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[Hoffer]

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Tunnel bottom on today....
Went with 3/8"

[Hoffer]

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Some more progres today.

[Hoffer]

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[Hoffer]

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[W2F a V-King]

Very Nice Work !!

[home made tunnel]

Does it float yet ?! :)

[Hoffer]

Does it float yet ?! :)
Probably would float if I toss it in the neighbours pool, not quite ready yet.
I have to finish front sponson bottoms..... the 3/8 wont make the curve I am going for. I may have to use 1/4 and glass or sections of 3/8 and glass over,either way ill get there.
Once the bottom is done the sides should be fairly straight forward. After the sides are on I will climb in and finish seal/paint the inside before installing the deck.
Its coming along though.

[Hoffer]

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[Hoffer]

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[Hoffer]

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[home made tunnel]

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Is that a joint on the skin lapped, or is it just a butt joint? You've used a heck of a lot more hardware than I did haha. Is it All stainless?

[Hoffer]

Is that a joint on the skin lapped, or is it just a butt joint? You've used a heck of a lot more hardware than I did haha. Is it All stainless?

Its joined to the bulkhead and but joined to the other skin, I tried a few times to use one piece.......lets just say it was an expensive lesson. All the hardware is stainless, need a lot to hold that 3/8" ply curve tight.
I dont know how you pulled it off with 1/2".
What did you use to water tight your hatch?

[home made tunnel]

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Its joined to the bulkhead and but joined to the other skin, I tried a few times to use one piece.......lets just say it was an expensive lesson. All the hardware is stainless, need a lot to hold that 3/8" ply curve tight.
I dont know how you pulled it off with 1/2".
What did you use to water tight your hatch?

For all my seams, an epoxy fillet seam reinforced with fiberglass will be stronger than all the screws in the world lol. It also means less holes in the boat. I held it in place with copper wire (like sewn together). Once the copper was in, i could twist it with pliers to pull it in tight. I also used a long pipe clamp to pull the sides in while the glue dried. The one place I did use screws was the tunnel bottom up to the front abreast beam. You can see the screws in picture 3 underneath. Those are like 2.5" or 3" long screws. My 1/2" ply may have bent easier because it was very light weight African Okume mahogany marine ply. Lighter / less dense / easier to bend. Only 37 lbs per 4x8' sheet. https://www.boulterplywood.com/

The hatch I have in the footwell / firewall is a purchased hatch. It's plastic, and about 20" wide by 10" tall. That keeps everything up front bone-dry.
The rear hatch behind the seat isn't 100% waterproof. I just used some sticky tape rubber foam from the hardware store. it was the Double-D style like this: https://www.homedepot.com/p/Frost-King-5-16-in-x-1-4-in-x-17-ft-Grey-D-Center-EPDM-Medium-Gap-Weatherseal-Tape-V25GA/100081207
I'll post pictures in the next post of how I built the hatch. I don't have any pictures of the weather-strip seal on it. That will have to wait till next spring lol.

[home made tunnel]

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So this is the rear hatch I made. What it doesn't show is the 1"x1" angle aluminum that I installed all around the inner edge, 1/2" under flush. The hatch comes down and rests on that 1x1 aluminum angle.
I layed down painters tape on the angle, and on the boat parallel to the seams from angle to boat, applied Marine 5200 sealant, squeegeed into the corners, then pulled up the tape revealing a perfect fillet seam of 5200 silicon in the seam from aluminum angle to the boat. The angle was through-bolted to the boat by the way.
Then I laid the rubber weatherstripping from home depot onto the aluminum angle, and the top hatch comes down and rests on the seal. So it's not 100% water tight, but if I ever stuffed the boat, the majority of the water would run off the top side. Wish I had more pictures of the seal.

I tried to add a curve in the plywood anywhere I could - especially places that would see weight, like me standing on it. The curved hatch cover is MUCH stronger than a flat one. This doesn't flex at all. I guessed at the radius, and over-bent the hatch when installing the stiffeners underneath. When I pulled it out of the jig, it flexed back a tiny bit and matched perfectly to the hull. That was a good guess!

[Hoffer]

Thanks Home made.... I think we are using two completely different build techniques for similar boats.
l agree on the screws, only using methods I know work for me. The boat was designed to be built this way,mainly from my reading how to build. I don't think my wood working skills are at your level, I'm more comfortable with metal and engines.
Thanks for the info on the hatch,I'm far from that but my mind is 10 steps ahead of where I am now. I am starting to skin the sides now but out of wood ( also using Okume) going sledding this weekend so I'll take a break......long weekend in Canada.
Thanks again.

[home made tunnel]

LOL I agree about the different techniques. And thanks for the compliment on my woodworking skills. I must say I am NOT a woodworker, nor ever considered myself. I too am much better with welding, metal, and all that jazz.
Don't worry about 10 steps ahead - I was thinking about that stuff while I was still designing on a napkin! I still have that 90hp restored Force if you want it.

[Hoffer]

Thanks, Ill let you know on the motor when I get closer.
I think ill put it in the water before rigging it and see how the balance is, put some weight where the engine and fuel tank will be to see what im dealing with.

[Hoffer]

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[home made tunnel]

PRogress! I think I see why you couldn't bend the plywood where you wanted to - it's a relatively sharp bend there. Mine were all gradual in comparison.
Hey, more screws in front will help balance your center of gravity! Bonus.

In addition to curving from front to back, it looks like there's a twist in yours too. nothing wrong with that, but VERY hard to do with plywood. I've learned you can either TWIST, or bend plywood. You can't do both at the same time. In this picture, on the left is how My boat was built. All the frames were parallel. I think yours is more like on the right.


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[Hoffer]

A little progress.....and I must be amazing,twisting and bending plywood.
My new motto is if you use enough screws anything is possible, very sleight but its there.
You have a good eye mine is definatly the diagram on the right, looks more impressive than the pictures....so far.

[oldschoolltv]

Pads look very flat at the rear, no dihedral?

[Hoffer]

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There is 8 degrees.

[Hoffer]

8 degrees is close to the minimum acceptable for cat/tunnel hull as far as my research goes. The boat is small and an amalgamation of a few different designs. It's called the SLX3....The S and L are for sorry Lori (My wife's name) and the X is experimental......and its my third boat, she hates boats.

[oldschoolltv]

Flat is fast but too flat and you get a porpoise.

[Hoffer]

Yah, there is a fine line there. Balance and C G come in to play, everything has to work symbioticly to be great. That being said if for some reason it doesn't completely work out I'm cool with that.
It won't be slow and I'll drive through it.

[oldschoolltv]

Love these projects I wish I had the time to do one, have you decided on power yet?

[Hoffer]

Not yet,but it should hold more than you think. May start with 60 to 90 then go from there.

[Hoffer]

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[home made tunnel]

That's a cool little drawing / rendering. I like the nose

[Hoffer]

That is what I am hoping to end up with.......ish

[XstreamVking]

I would have used a 3rd variation to build them both. I have constructed running plugs intended for glass molds to be built from. Start with a light wt. frame, and using 1/8'' ply with epoxy glue sandwiched inside and screwed in place till hard. Remove screws lay next pc. Build up till you get the shape/thickness you are after. Sand down the surface to make the shapes exact from side to side and front to back. Add features to the surface like strakes etc. using thicker ply pcs. sanded to shape. Glass over. No screws needed. Not saying either way is wrong, but I have used another method, and i'm sure there are many more.

[Hoffer]

I have seen that method before and I'm sure it works well. I decided to go this route as I am more comfortable with wood than working with fiberglass. It's all just a means to an end,doesn't matter how yo get there as long as you get there. Only been 3 months since the first piece of wood was cut, if I wasn't slightly overbuilding it may have gone quicker.

[home made tunnel]

I have seen that method before and I'm sure it works well. I decided to go this route as I am more comfortable with wood than working with fiberglass. It's all just a means to an end,doesn't matter how yo get there as long as you get there. Only been 3 months since the first piece of wood was cut, if I wasn't slightly overbuilding it may have gone quicker.

Any updates?

[Hoffer]

Yah....just filling all those screw holes you loved so much, getting work done when I can. Minus 20...celcius here in canada. I'll post some pictures when its primed before I flip it.
Still going strong.

[FMP]

Almost shorts weather, sun's great.

[Hoffer]

I sent my wife and daughter to Florida, maybe I should have gone with them. Work gets in the way of boat builds.

[Hoffer]

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Primed.... a few small things to address.

[home made tunnel]

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Primed.... a few small things to address.


Heck Yea !!! Paint!!! Looks great.
I went to florida last week with the wife n' daughter. Too hot! Sweating @ 78*. Came home to sunshine in New England, and I was I a t-shirt @ 45* haha.

Glad to see all those screw holes filled!

Gotta invite a few friends over for beers and pizza to help you flip it. Do you have a trailer for it yet?

[home made tunnel]

I still have a 90hp i'll sell ya for a great price ;)

[Hoffer]

I still have a 90hp i'll sell ya for a great price ;)
Just fairing a few spots,sanding primer etc...... I think I will finish coat the bottom before I flip it over, I'm trying to decide weather to leave it white or go a light silver.

No trailer yet, may just buy a used boat on a trailer and modify it for mine.

I am keeping your motor in mind.

[Hoffer]

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Finally got it flipped right side up!

[W2F a V-King]

Very Cool !!

[XstreamVking]

I think it will porpoise w/o tabs. But, I could be wrong....Great project building your own boat.

[home made tunnel]

How's the twist? Is it still a little flimsy? Mine was until I got the deck battened down.

[Hoffer]

How's the twist? Is it still a little flimsy? Mine was until I got the deck battened down.

Three of us picked it up, two up front and one on the stern with no noticeable flex. Should be quite solid once the deck is on.

[home made tunnel]

Been a month... WHATS UP ! ?

[Hoffer]

Been a month... WHATS UP ! ?

Got the Spring Honeydo list to get through, then back at it.

[home made tunnel]

Got the Spring Honeydo list to get through, then back at it.

It's been another month - - BOATING SEASON IS UPON US! does it float yet?

[Hoffer]

Haven't tried to float it, work is crazy busy. I'm not to far off but will be next summer, I only have vacation in winter.

[Hoffer]

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1992 Johnson 60.
Just started work again.

[Hoffer]

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[Hoffer]

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[Hoffer]

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[Hoffer]

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[home made tunnel]

Cool! Do you have a hull weight yet?

[Hoffer]

Cool! Do you have a hull weight yet?

Nothing official, 2 of us can still pick it up without to much of a struggle. I'm thinking it's in the low to mid 300 lb range.
Now some more messing around getting the deck smoothed out, playing with the interior etc.
I am trying to figure out the dash thickness, currently mocked up in half inch. 455216

[Hoffer]

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[Hoffer]

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Some picks of the interior layout.

[Hoffer]

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Deck is down and the dash is in, after a lot f sanding and finishing work I should have something I can bolt the 60 to.
The steering has been mounted and cable routed, a bit of a pain as its left hand helm.
Going to the boat show in a couple weeks, need insruments (any suggestions welcome) also need to figure out seats.
Any input on first prop to try would also be much appreciated, the one on the motor is not in great shape. The prop is MI Wheel Vortex 13x19, maybe a good starting point but this is all new to me.

[home made tunnel]

I like the lines of the hull. Sharp looking. Definitaley has the Mini-boat look, kinda like a caricature drawing.

What year is the 60hp? Assuming it's the Johnson in the background. We can give you a good idea of prop if you tell us the gear ratio of the lower unit.

If it's not too late, I suggest putting your battery and fuel tank in the bow. I made that mistake with mine - but I also have close to 400 lbs hanging on the back of mine with the 115hp, hydraulic steering, and the jack plate.

[Hoffer]

I like the lines of the hull. Sharp looking. Definitaley has the Mini-boat look, kinda like a caricature drawing.

What year is the 60hp? Assuming it's the Johnson in the background. We can give you a good idea of prop if you tell us the gear ratio of the lower unit.

If it's not too late, I suggest putting your battery and fuel tank in the bow. I made that mistake with mine - but I also have close to 400 lbs hanging on the back of mine with the 115hp, hydraulic steering, and the jack plate.

1992 Johnson J60LENE.
Weight 254lbs
Gear ratio 2.42
Wet rpm 5000 to 6000 rpm

The battery will be in the back, the fuel tank will be portable to start off.

The whole package should be in the 750 to 800 lb range, rough estimate until it gets weighed.

[Hoffer]

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[Hoffer]

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[home made tunnel]

Looking great! ALmost there! It will be ready for boating season. Come down to new England and lets do some river running and a photo shoot of home made plywood mini cats haha.

So with some guess work.... I'm going to assume a 50mph top speed. using the Mercury prop slip calculator ( https://www.mercuryracing.com/prop-slip-calculator/ )

at 2.42 gear ratio, 6000 peak rpm, 50mph, and an IDEAL 7% slip ratio... that calculates to a 22.9 propeller pitch. (22 or 23).
all things the same... but 40mph top speed.... it gives you 18.32 for propeller pitch.

If you find any CHEAP prop from 18-21 pitch, that would be a great starting point. Once you have actual GPS speed, and an RPM... you can get a much better guess for ideal prop pitch.

So, 18-21 pitch, whatever you can find on the cheap as a base-prop. 17 pitch would probably be too low. Probably tach out the motor before peak speed.

[Hoffer]

Looking great! ALmost there! It will be ready for boating season. Come down to new England and lets do some river running and a photo shoot of home made plywood mini cats haha.

So with some guess work.... I'm going to assume a 50mph top speed. using the Mercury prop slip calculator ( https://www.mercuryracing.com/prop-slip-calculator/ )

at 2.42 gear ratio, 6000 peak rpm, 50mph, and an IDEAL 7% slip ratio... that calculates to a 22.9 propeller pitch. (22 or 23).
all things the same... but 40mph top speed.... it gives you 18.32 for propeller pitch.

If you find any CHEAP prop from 18-21 pitch, that would be a great starting point. Once you have actual GPS speed, and an RPM... you can get a much better guess for ideal prop pitch.

So, 18-21 pitch, whatever you can find on the cheap as a base-prop. 17 pitch would probably be too low. Probably tach out the motor before peak speed.

Thanks for the prop advice, I will try and find a 19 and 21 p to try. I wasn't going to put a jack plate on it but I feel like it will need one, but now I'm worried about low water pressure.
You said you had one on your tunnel, just wondering about how much setback? Trial and error I guess, thinking 6 inch or so but was not planned for originally.
Just trying to get as much installed and mocked up before I tear it down for final finishing.
Would be great to get together and compare the two 1 of 1 boats, see if mine floats first.

[home made tunnel]

I haven't had any issues with low water pressure. Seems I can't get on plane before I run out of water pressure. Like if I raise it too much, I blow out / cavitate before even getting on plane. Soooo never had a low water pressure issue yet.

Here's the manual jack plate I have - Only 26 lbs but is nice for variable mounting heights. Also, if you ever want to pull the motor off the boat, it's WAY easier pulling it off the jackplate, than pulling the bolts out of the transom.

https://bobsmachine.com/product/convertable-mj5-2-5-or-5-setback-manual-jack-plate-200-hp-max/

[Hoffer]

I haven't had any issues with low water pressure. Seems I can't get on plane before I run out of water pressure. Like if I raise it too much, I blow out / cavitate before even getting on plane. Soooo never had a low water pressure issue yet.

Here's the manual jack plate I have - Only 26 lbs but is nice for variable mounting heights. Also, if you ever want to pull the motor off the boat, it's WAY easier pulling it off the jackplate, than pulling the bolts out of the transom.

https://bobsmachine.com/product/convertable-mj5-2-5-or-5-setback-manual-jack-plate-200-hp-max/


I am going to set the engine back 6" to 8", looking at the TH marine manual jack plate.
What height did you eventually find worked best for your boat?
I will start low and work my way up until it runs out of water.

[Hoffer]

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I had to straighten out the skeg and smooth out some dings and scratches. To be expected from a motor off an old runabout.

[Hoffer]

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I found 2 props to try out. OEM re manifactured,
Both are 12 3/4" one 21P and one 23P.......price was right.

[home made tunnel]

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I am going to set the engine back 6" to 8", looking at the TH marine manual jack plate.
What height did you eventually find worked best for your boat?
I will start low and work my way up until it runs out of water.

I didnt' even set it back that far. I believe its set around 2.5" of setback. That manual jackplate can be flipped into several different positions.
For height, a good starting point is even with the bottom of your sponsons. I've gone up to 3" higher than the bottom of the sponsons, it stopped some porpoising but didnt net me much more speed.
You'll find the higher you go, the harder it is to get on plane, and the less your trim has any effect. I don't think it will matter too much, as it wont be a 100mph boat anyway.

So my 3rd picture, you can see the jack plate almost maxed out. That's about 3" above pad height. Since this picture was taken, i've moved the engine to the bottom bolt holes (most height out of engine clamp bracket), and brought the jack plate back down. I'm not sure if your motor even has various mounting holes. Either way, you've got a lot of room for adjustment with a jack plate.

[Hoffer]

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I didnt' even set it back that far. I believe its set around 2.5" of setback. That manual jackplate can be flipped into several different positions.
For height, a good starting point is even with the bottom of your sponsons. I've gone up to 3" higher than the bottom of the sponsons, it stopped some porpoising but didnt net me much more speed.
You'll find the higher you go, the harder it is to get on plane, and the less your trim has any effect. I don't think it will matter too much, as it wont be a 100mph boat anyway.

So my 3rd picture, you can see the jack plate almost maxed out. That's about 3" above pad height. Since this picture was taken, i've moved the engine to the bottom bolt holes (most height out of engine clamp bracket), and brought the jack plate back down. I'm not sure if your motor even has various mounting holes. Either way, you've got a lot of room for adjustment with a jack plate.


Thank you. Just trying to figure out how much adjustment I may need, starting point to mount the jack plate. The motor has multiple mounting holes as well so there should be lots of room for adjustment. I will most likely order the TH marine 5.5" manual plate.
Starting finishing work this weekend....time to get the shop dusty again.

[Hoffer]

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In primer.

[Hoffer]

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Primer sanded, filling and re priming. I think one more time before paint, a guy could go crazy looking for little imperfections.
I think I'll get it in the water and shake it down, scrape some rocks etc. before I get to crazy on making her pretty.

[Hoffer]

459828459829

Finishing the bare hull and mocking things up for final assembly. I have been picking up parts here and there since I started the build, kind of nice to start bolting them to the hull.
The deck and hull are not perfect by any means, I never claimed to be a body/paint guy......but it will work for testing.
If it works as expected then I will put the extra hours in to make her pretty.
For me it is a therapeutic exercise in design and function, I am learning a lot.
Over the next few weeks I will be rigging and looking for the few parts needed for completion.
Starting to look like something now.

[Hoffer]

459833

[Hoffer]

460192460193460194460195

Going together now.

[home made tunnel]

She has seen sunlight ! That's a milestone!
I can't wait to get our mini's next to each other for a photoshoot haha.

So no fiberglass / epoxy sealers anywhere?

[Hoffer]

She has seen sunlight ! That's a milestone!
I can't wait to get our mini's next to each other for a photoshoot haha.

So no fiberglass / epoxy sealers anywhere?

The two boats together would be a good day on the lake for sure. The primer and paint I used are epoxy paints... many coats. It stands well but for now it's a little rough, it will hit the water all white for now. If it needs some minor changes I can do them easily with no fiberglass to go through, if it runs well I will spend the time to make it pretty.
I just spent time with Cradle Ride, a local trailer builder who came and measured it up, should be on a trailer in a week or so. Good local guy was into a custom build and gave me a deal I cant refuse.
One way or another we will see what happens this summer.

[Hoffer]

460949

Trailer should be ready tomorrow.

[Hoffer]

461004461005

Trailer is here.....looks legit.

[Hoffer]

461052461053461054

Bolted the old 1992 Johnson 60 on today, now its starting to look like a boat.

[Hoffer]

461189

Steering cable and speedo hardware installed.
Control cables and wiring harness to engine installed.
I dont have fuel tank and fuel lines yet.
I am going to run keys power and tachometer signal wiring directly from the engine....someone's been under the cowl with wire cutters.
The battery is in and all trim and tilt works perfectly, I will bark it when I finish wiring everything. It's tough getting what I need to continue right now.

461191

Anyone know where to get reasonably priced seats like the ones in the picture? I may be sitting on the floor to test her out.

[89LASER]

Go on Ebay and look up marine seats. Some nice seats on there.

[Hoffer]

461674

Led's under the dash to much? Had an extra switch.

[Hoffer]

461675

Nav lights.

[Hoffer]

Barked the motor today.... sounds healthy and runs good.

[home made tunnel]

Checkout dune buggy seats. Or forklift seats. They have cushion and are relatively simple.
its looking great !

[home made tunnel]

461946

[Hoffer]

I think if I can find anywhere that I can get ahold of these they will fit nicely.

462386

Just wondering now how long I'll have to wait to go and test.

[Hoffer]

Modified the seat frames, I think I'll finish them and have someone do the upholstery. 463399463400463401

[Hoffer]

464157

[Hoffer]

467958

So its loaded up, gathering tools and props.....only the 21p and 23p oem Johnson props. Nervous and excited at the same time. No seats yet but should be able to see how she floats and get some idea of what I'm dealing with......we will know by Saturday night one way or the other.

[Hoffer]

467959

This is where I'm starting with engine height, still worried about water pressure.

[XstreamVking]

Looks like you will be ok. 1st ride is always a learning curve.

[oldschoolltv]

Looks great, get a torque tab welded on that skeg if you plan on running the motor higher. Keep us posted.

[Hoffer]

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[Hoffer]

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So I ended up having to raise the engine a lot, and it needs to go up still. I will need to remoove it from the plate and raise it there then start again.
Was running a 21p stock Johnson prop.....

1st run was 41 mph @ 4000rpm

2nd run raised the engine 1" and ran 45 mph @ 4400rpm

3rd run raised engine to upper limit of jack plate and ran 49mph@ 4900 rpm

4th run added 75lbs of top soil to the bow and ran 52 mph @5100 rpm

Water pressure still verry good and the boat is stable, so I think the 21p prop is in the ballpark just need one that will work better with this boat.
There is a bit more speed in there I'm sure, going to move the fuel tank forward and go from there.
I have some good pictures of the boat running but having trouble posting them at the moment......trying to figure it out now.

[Hoffer]

468080

[XstreamVking]

Running good, nice lil boat!

[Hoffer]

Running good, nice lil boat!

Thanks, I am pretty happy with it. Still a lot more messing around to go.

[Hoffer]

468306468307

So I raised the motor up on the jack plate as high as it will go....for now.
In the process of moving the fuel load forward as well.
Could use some input on a better prop to try in the 21p range.
The last run I posted the prop shaft was 2 1/4" below the lowest part of the sponson. Now it is even.....the jack plate is 6" set back, I dont have low water pickup.