Best roughwater boat?

[Alan Power]

Just want everyone's opinion, what do you think is faster and more forgiving in rougher conditions, say a 15" chop. A mono, a tunnel or a modified or ???

[joe-doggs]

I live here in Sad-attle where we have real water - as well as piss on a platter - I sold my Hydrostream Voyage XT because the rough water made it a misearble experiance - the guy I bought it from had a bad back & had to get rid of it for the same reason..

[Alan Power]

Could people that select OTHER in the Poll please specify what type of hull they believe to be better. Also could anyone that votes for any hull type please give a short reason for their choice if they can spare the time.
Thank you to all that vote.
Many thanks Alan.

[TUFFboat]

These discussions always go around and round. To attempt to answer it best you must be very specific in your parameters. So your only condition is 15" chop. At what speed? If your going under 75 mph the smothest ride is a true Vee. Its not the most efficient ride. After 75mph a air entrapment hull will be smoother because you are lifted out of the chop, therefore not experiencing the depth of the water. A tunnel or cat would be smoother than a mod VP because of reduced wet surface contacting the offending waves.
Are you now going to ask what is faster with the same HP, same size and length and most important, the same weight? The lift that the bottom style produces tells all.

Vee- not much lift, slowest at high speed, smooth ride

Vee with pad- some lift, faster at high speed, pad starts to pound on waves

Mod-VP- more lift gained from air and water, faster still, more surface to bang off waves, rougher at first until you get air lift to put you over the top. If the waves are big enough to fill the tunnel, than its rough again.

Offshore cat-big lift from the air, as long as you dont fill the tunnel with waves ( banging off the bottom ) the ride is as smooth as the Vee with the same deadrise at slow speeds. Very fast after it gets on top of the air. It will continue to be the fastest from that point on, no matter what conditions.
Dont confuse passenger discomfort ( big waves hammering on the bottom of the tunnel ) with lack of speed ability. The faster you can go, the higher you will rise and the smoother it will ride.

What the best? depends on the ride you want, at the speed you want.

Dont ask what is the fastest accelerating hull or best turning boat is now!

[Alan Power]

I know this topic has been tackled many times on this board but for much larger boats, the boat in question would be a 14/15' that I wish to design for race/pleasue. Taking that each example is of similar power and weight and to be used in sheltered coastal waters.

[TUFFboat]

I seem to have killed your thread, Opps. I've been thinking about your project. First, how fast do you need to go? I can't help thinking how fast 100mph would seem on a 14' board. Or the question might be how much HP will you have? If I would guess, I would say the weight of a V4 might be the max. Since 14' won't do much in the rough no matter what shape it is, I would go for a flat water design and only use it there. My thought would be to build a full deep tunnel boat. Remember, if you can't get it over 70-75mph don't bother with air entrapment.
Good luck

[sho305]

I asked a couple of times about an 18' boat to run lakes....gave up after a while. I need something people are not afraid to ride in is all, that will take a wake reasonable. My vee will plow about anything if you trim it down, and then it slows down too, but I can still do medium speeds when it is busy out. Like the tunnels but just don't know.

[shadowman]

With a small hull I,d try a v tunnel. I run a 20' vt bass boat and It does a decsent job at about any speed. The only thing I notice while running in good chop is about 5 more mph. I've never run a full V in rough water but I'll bet It dos'nt speed up much, but would probably give a smoother ride at lower speeds due to the cusioning efect of these hulls. Just my two cents.

[sho305]

A vee will go faster in a chop than smooth water for sure, as it needs the extra lift. It will until the waves get so big you can not keep control anymore, or you are not good enough to drive it:D I think a vee rules in water too big for the boat, if you can make an air hull bigger than the water it will be faster of course from the air lift. Take offshore, and you see the deep tunnels doing well, because they kind of cut like a vee, have air lift, and are normaly longer than the waves(can bridge). I have not seen any little 'split vees' like the offshores though. See little <20' Skaters but they are not the same, do not have that big bow for rough water. Has anyone seen one? Check the bow on this Motion: http://forums.screamandfly.com/forums/showthread.php?s=&threadid=23581 See how big it is, no stuffing that if on a little hull. Not knowing if it would work of course...

On the other hand I have been told(as in the other post) that air does not work at lower speeds, so a single hull is faster due to less wetted surface....so a vee/pad is a good choice. I like that Bullet 13' for a rough water boat myself. Not sure how fast it is though. Either way, it really depends on conditions.

[TUFFboat]

In Europe they race offshore in tiny cats, they look about 18' ?? They are designed for the big water in that they have blunt stumpy bows, sort of an anti stuff bow. So it is aready being done. The problem seems to be that you can't scale everything. For example... take a 46 Skater (extreme example) with twin sterling 1300hp motors (a real Vee crusher) that runs around 160mph and has 3 people on board. Now lets consider your 18' tunnel with 200hp and those same 3 people. The 46 dosent know or care how many people are there, the 18 is effected greatly every time you add weight. Even the ablity to get on the air could be lost. The 46 starts to cruise over 80mph, in fact it runs like sh#t below that. The 18 may never get there, and may always have the tunnel full of water(read 'rough ride'). In the 46 your watching the girls on the passing dock at 120, in the 18 you would have a death grip on the wheel and would'nt notice a naked girl next to you at 120.
Every speed range has different rules effected by hp, weight and water. Consider with honesty what your realy need, then chose.

[Alan Power]

This is exactly the kind of info I was looking for, just want everyone's own opinion. I have a few sample design's done of different hull configurations but want a clear idea in my head before I start the final design process.

Tuffboat; the cats we race here in Europe are argo 18's and hydrolft 21's mainly with 2 liter mercs, but I'm thinking a bit smaller.
Also, when you say full deep tunnel- how deep do you mean? I'm thinking 12 - 18 inches?

I'll try and post a drawing later to show you what I have in mind.

Thanks again, and keep em coming any thoughts from anyone... thanks

[sho305]

About 15' you are thinking? What hulls race in your conditions and win that size? I like the idea of the stv euro, they used a good race hull and put a people deck on it;)

[Outboards Unlimited]

Gotta great rough water mod vp boat called a vision craft. My now 20.5' laser 380, or 16' seebold will not out do it in rough water. I think the vision is 18, 19' . ? .

Mod V P!

[Alan Power]

This is kind of what I have in mind, I will probably increase the deadrise and try to fit a rear bench in there if there's room. The hull is a scaled down version of a 21 footer I designed in college with some changes to the steps and bows.

[sho305]

Hehe, that is just what I was thinking. I would think you need to keep the nose kind of blunt on this or your running surface would be too short. If you can squeeze seating in the back you are all set. I like it, just hope it would run as good as it looks. Likely run at least good anyway.

[TUFFboat]

Looks good, sho305 is right about the blunt nose to increase your running surface length, Also I would guess that you would not need the notch in your case. That would get you more length again. If it were me, I would put some Vee in the tunnel bottom for some strength. I might only make the back seat like a kid size thing and focus on proper layout for the front seating.
There is a guy on these pages somewhere 'Jim' that has a pubication 'Secrets of tunnel boat design'. That may give you some way to calculate the balance, and the amount of compression in the tunnel (lift), step location and depth, width and depth of tunnel. I would build a running wood plug and try different strakes all over. Don't forget the deflector for the gearcase. Always look under everyones boat, good or bad.
Keep us updated.

[TUFFboat]

By the way Sho305, the Motion is a knock off the 24 Skater, which was the stuff KING. But don't blame the boat though, it was so good it would take you so far out into no-mans land and then leave you there if you did'nt respect it. It was a short boat smoking a whole lot of bigger ones.

[sho305]

Yes, that hull is a performer and can get you into trouble. We stuck to vees here for Lake MI. The waves are so tight you need a real big boat to get away from a vee. They are kinda safer too for playing, and you can spend more on the motors that way. Caught a test of a new Daytona (about 25'?) with twin Merc BBC HOs on the tube that did 103.5mph stock. He was in the smooth getting aired out. I was glued there until they finished!

I think the bigger tunnels have the bigger bows looking at them closer, maybe they figure the smaller ones(<20') will not get in the rough so much? I don't know, maybe with more rise for rougher water they slow down? You still should have better stability with the dual hull(especially in chop); but like any small boat you can get in trouble. I saw a Talon open deck on iboats for sale that had a nice tunnel with sharp bows and a small center pod. Maybe also checkout the Virage hull for ideas, but I am guessing your type of bow might cut better when you need to trim down. I am trying to find more about use of inverted vees too, like if you could use them on a tunnel somehow.

One thing I would play with, is stretching the cockpit forward for the most room kinda like the stv euro is some. In that case a relief might help offset it, but yes you will need all the running surface you can get. I thought about running the tunnels behind the motor some, but I do not know how that affects handling on a tunnel, or how you keep the bow up then. I see some like tunnel extensions.

I have not figured out how you can do it, but I would love to have a open bow tunnel or modvp, or a convertable you can close for speed runs somehow. Even access up there is nice for lake boating. I have a rolltop cover on my truck bed, that got me thinking. It works great, like a garage door and is light aluminum. I wish I had one on the whole boat! Could cover it in 10 seconds and lock it too.

[Markus]

Alan,

To have a look at some small European offshore hulls, go to the Swedish Powerboat Federation at www.svera.org.

The hulls in the 1l class should be in about the size range you are thinking of.

[Alan Power]

The book you talk about by Jim Russell, I have ordered about 3 weeks ago, should be here any day now, hoped it would have been here for christmas!
Yeah, I was wondering about the notch, what about building extension aft of the tunnel like installed setback? or maybe just use setback brackets?
I think I may squeeze a rear seat in, if I lose the lockers, just put them there to fill the space, the original design only required 2 seats.
Also what do you mean by gearcase deflector?

Sho; I had thought of pushing the whole cockpit forward a foot or two but on drawings the boat started to look very snub, as it has quite a high freeboard. The STV was one of the boats I looked at when researching this boat, thats how I found the S&F site, thats how long this project is going on... so don't hold your breath!

Markus; sorry I couldn't find the boats on that site, only the first page is in English. Could you post a link to the boat you are talking about, as I would be very interested in seeing these boats. Thanks for letting me know. And also that's a very nice site you put together with engine formulae.:D

[trbocharge]

Alan,

My buddie mounted a 2.4 mod vp motor on a 15 foot express cat............it was an animal that was a little tough to tame..........ran well but get the boat off balance, hit a wave from the side and the rotational motion of the flywheel and rotating assembly would turn your undies colors.........he mounted a 20 incher on it..........about 8 years ago.......a shorty would help today..........

Outboard U..........the 380 ray is a real runner in chop.......you have a 20'5"er.? I thought they were 19.........

Regards

[sho305]

I'm assuming by gearcase deflector he means a center pod; I could be wrong. I think the tunnels work better with a pod to break water for the drive so you can run it higher....that is what I have heard.

You may be seated forward as far as you can now, just a thing to keep in mind I meant.

If it were me I'd like to see a 17-19' size for that boat with some kind of access to the bow. I like to tie up the bow and fish from up there. Even at 15', that would be a kicking boat! They fit a back seat in a Viper, should be no problem there.

I found the Talon, check this hull out and see the pod for the drive. Note how deep the bow is.
http://www.iboats.com/my_iboats/view_images.html?ad_id=13170&img=2&ref=boats.iboats.com/talon/center_console_boats--1007/13170-ad.html&count=1

Just out of curiosity, how hard would it be to make one out of wood? Of is that what you're thinking?

[TUFFboat]

Wow, sounds like your commited to this project! The deflector in the tunnel protects the expossed part of the motor from the dirty water coming through the tunnel, When we raced triples, the middle motor would need twice the maintainance of the outside two because of the beating it would get. If your tunnel is deep enough (high enough) to expose anything other than below the cavition plate, you need to build a deflector just in front of it.
If you extend the tunnel back past the transome it makes the boat think its longer. If you make the extention trimable you can use it for balancing the boat. ie. the motor trim is bow control and the tunnel tab is tail control. It will also stuff you real hard if you use it wrong. Allan was right about using motor extention bracket but only if you need it to fix balance.
What motor are you thinking to use? What is your target speed?

[Alan Power]

How far forward should the deflector run? I will probably 'V' the tunnel roof slightly. It may even give more legroom in the front, this is the main reason I can't push the cockpit forward as the tunnel roof sweeps up restricting leg-room.
How much farther can the drive in the center be raised above the lowest point on the transom?

To answer your questions, I am still uncertain as to what engine to use, any insight would be great. I would like to run about 80, I think!!!

Sho; The finished boat I plan to produce in GRP but the no. 1 hull will be made as a running plug, either from plywood or 'one-off' foam core, I think this would give a more realistic weight for the finished boat.
Have you any experience with boat building, if so it would be easy enough to build. or... I could design it and loft it, send you the building offsets, let you build it, test it and tell me if it works. LOL :D :D

[sho305]

A 15' at 80mph....maybe 120-140hp? I'd love to make one if I had the time, and a bigger building for it. Maybe some day! Checking out plans you can get, but they are old designs and not too exciting. I have only done repairs to transom, stringers, floors, smaller repair, and autobody repair. Been around one boat maker when they were designing and building boats some, so I am far from a pro. I understand most of the concepts though. I would not be afraid to try it at all. Mostly a matter of a good design and doing a good job.

I have that old Chriscraft with a round bottom, and I am really thinking of making a whole new bottom for it with a pad. A Ford small block in a 19', I figure a minimum 12" pad, vee, and negative chines to hold the splash. The chines are round now. I only have to figure stringer sizes, and how to mount the motor in the right spot too. It is a heavy old 40mph boat, so how can I go wrong? I'll just use plywood for that thing and copy my easy riding Bayliner pad bottom with more lift for the weight. Have to get the space to tear it down first.

The pod- The talon looks to have it an inch or two higher than the rest, did you check that link out? I am guessing that would be best. It is very small, so likely affects ride little. I bet it is not that long, need to find one and look. I also see many modvps/tunnels have a step about 2" at the bottom of the tunnels to control spash in the tunnel.

There are some on here with 200 Mercs on little skaters!

[Firestarter]

TUFFboat, is in the middle of building his own boat(s). He is a wealth of knowledge, has real world experiance, has the records to back it up. And is to be revealing his creations at TIBS, next week.
I thought that people should know, that there is gonna be a new mini offshore player in town, that will rival anything ever built, and our wealth of hidden info in TUFFboat will be revealed in his new Toys.
Sorry, I had to blow his horn, a little, but you are getting some of the more qualified answers.

RT

[sho305]

Oh sweet! Can't wait to see it. You mean this boat show?: http://www.discoverboating.com/boatshows/toronto/index.asp?bhcp=1

[Firestarter]

Bingo

[Alan Power]

Thanks firewalker, I had a feeling I wasn't being fed BS. I too hope to go to production with this or a similar boat in a mini offshore class.

Sho; I checked out the talon, I new about center pods just never heard of them called deflectors, thanks. I have looked at plans on the internet and found they were all old too.
Building boats, as long as your not afraid to try you might as well. I went to university for 3 years and studied boat design & construction and I still reckon I learned more in the real world, by making mistakes! why not try something small, a 10' single seater tunnel?

If you do go ahead with that chriscraft rebuild, there are formulae for specifying stringer and engine bearer sizes. Read, boat strength for builders, designers and owners, by Dave Ger. Most of the boatbuilding sites have it online purchase.

[Firestarter]

I would not call a center pod a deflector.......look at a 21 skater to see what TUFFboat means.

RT

[Alan Power]

What kind of boat are you building, if you dont mind my asking. Or will we have to wait for the unveiling.:cool:
Good look at the boat show, and thanks for all your help.
Alan

[sho305]

Alan, the Chriscraft is just way cool old thing I will fix, just a matter of when. It was made with frame inside, then slats and the skin outside. Must have been before they knew how to build glass boats. I guess they would re-skin them. Mine is ok, but the slats are going, and the skin is loose and has cracked from the trailer. I fixed it, but stopped running it for fear of further damage inside. I think if I replace the bottom skin and frame it might even be lighter! Just need to figure out how to retrofit pwr steering to it now. One cable + V-8 I/O = hard steer;)

I thought of a small boat. If I had plans for a bottom I could figure out the deck. No plans though. Guess I could make them...had plenty of drafting....no time right now though. I was thinking about it, maybe one could use real thin ply, then glass and/or core it? None of the kits have a very complex shape, and I think you need to go there somewhat. (for a tunnel like this) I'll have to get that book, and atleast you'd have basic angles, sizes, etc. I saw a 24' with a big block that had 2x10 stringers, and the motor bolted right to them. I thought that would work in the Chriscraft using 2x6 or 8.

[Alan Power]

I am unable to find a picture of the skater 21, could you post a pic or a link to one, if you have one. I looked on the skater page but no 21 is it an old boat?

[TUFFboat]

The optimum motor height can be guessed at by presuming a few things. If you look at the transom and draw an imaginary line across from the inside bottom point of one sponson to the other (lowest point of running surface) That would be the theoretical heighest on the water the boat could run, without being a airplane. Now you need to guess how much will the boat actually dent into the water at optimum speed. Lets guess about 4", and draw a new line across thats 4" heigher. Think of that as the bottom of the boat. Mount your motor and prop according to there ablity relative to that new height.

If you did a center pod you can predict the motor height easier, you would accelerate faster, may corner better (depends), little rougher ride and a little slower. I think I like the idea of a pod on a 80mph little boat. Maybe check out the old mod vp 18' Seebold race Eagle. Instead of a modified Vee, its a modified tunnel.

Peter dosent build the Skater 21 anymore.

My boat... well, Im no hero designing something new, im just bringing back George Linders CHALLENGER 21 (Vee) with some updates. When George designed the boat he said he considered the best of all the technology of the day, and when asked what would you change today he said "nothing". But being of the same attitude as George at the begining, I will consider all the newest technology available today to simlply update his masterpiece.

You should know that FIREWALKER is restoring a very special version of the Challenger. Next spring I expect there will be alot of develpment around this hull style as a revival is afoot.

[sho305]

Challenger 21, have not seen much about it here, but there are a million boats out there too. What makes it different than others?

I think it is obvious a vee will be faster in a small boat, but this tunnel would be so cool if it does not have handling quirks. It would be able to run good speeds in a lot more water conditions, like lake running. Seems like it could be made to be close to a vee if done right. One problem I see is if you close the tunnel for lots of lift at the stern, what will that do to big water capabilities? Also can you use steps and inverted vees more on this? Cuda 21 seems to be having luck with them, but otherwise I see little of it on a under 20' hull.

[Alan Power]

be about right for determining the motor height but was unsure. I might not design a splashwell into the boat and mount the O/B on a jackplate always, any thoughts?
I saw Firewalker's boat on the thread 'Aerating the Pad', the red boat with twin O/B's, that is one beast of a boat! I saw Cuda 21's mold there as well, would like to pick his brains too, if anyone knows him.

Also, I reckon I should put spray deflectors on the inside of each sponson, any particular shape or just go with what the big offshore boats use?
And can the shape of these effect the prop's water?

Sho; what do you mean by inverted V's and where are they, on the sponson or center pod?

[pantera1]

80 mph will do 60 all dayin 3 footers and no drink spillage..

[TUFFboat]

Sho, why did you say the little vee is faster. If little Vees were fast than F1 boats would be Vees. Im not sure what you ment. The Challenger 21 has been copied legally and illegally so often mayby you have herd of the one of its offspring, Superboat 21, Shadow 21, Scorpion 21, Hammond 21, Stallion 21,... etc.

Allen, I like brackets on non race stuff, great adjustablity. You can always add more set-back if you need it.
Spray rails, excellent thought. I believe the primary intention for them is lift for acceleration and a by-product of cooling water spray for the gearcase. Hopefully Jim's book has more on that cause I'd be guessing more than usual. If all else fails copy the big guys.

[Alan Power]

Didnt quite know what you meant by cooling water.
Still waiting on the book though!

[sho305]

The vees? All the speed runs are made on Allisons right? Not knowing how they corner, but I guess not good enough to race? You got me though as we are talking about something race-able, and able to run in some rougher water so the vee don't really apply here. Nobody can make a vector run these days in a race, or make a new one that can...so far anyway. Maybe why bicycles are better than unicycles? Ok, thats apples and pears.

I think personally, I would rather have something like this for the lake running I want to do. I like vees, my Checkmate will run about anything you want for a 17'. It is slow though and I am not out on Lake Michigan(the Big Lake). Out there, the vee is the only way for a smaller boat.

I need a good smooth runner that will take wakes from other boats on lakes. Something that I can air out when calm and be pretty fast, yet not fly out of the boat from wakes and chop. I could be wrong, hell you know way more about it than me, and I don't see many 20' and less tunnels made for rough water at all. Most are pretty low like a stv. Do you know why there are no deeper small offshore styles out? With something like this I could venture out on lake MI if it were calmer. Are they not good at turning?

I would rather stay around 18' than go to 20'. I was thinking the tunnel would be more stable, and if you got it to run close to a big pad vee in speed, and yet better in the rough it would be ideal. Hope I'm not barking up a dead tree here.

[Alan Power]

Not knowing a lot about Alison boats I can not really answer your question, but I do know that a tunnel can haul ass when designed and set up correctly. That's why I'm doing all this research. And since I have been looking around I have found lots of little cat's from 10' to 17' and lots of different layouts. So they are out there but don't know why they are not more popular.
Check out this link; http://forums.screamandfly.com/forums/showthread.php?s=&threadid=26179&perpage=15&pagenumber=1

Two nice boats there!

I'd love to build about 18' but I don't think they would be as popular as a 15 here! Also trying to keep the affordable :D

As TUFFboat pointed out earlier, for either a cat or V of the size we are talking, the rough water capabilities would be similar. So it doesn't really matter which one you choose.

[sho305]

Allison is likely the fastest, most advanced, and lightest vee hull out there. They are expensive, and take some skill to fly.

How do you mean rough water will be the same? I never been in a Vector for example, but being a faster vee/pad hull I gather from here they are a handfull to fly, and not flyable in rough water. They don't like rough water at all. I can't believe this would not be better in rougher water. I don't care about wot, just want to get someplace if it gets rough. I would trade a few mph any day for better rough abilities, and better wake handling for when I miss one. My vee is much slower though, without a pad. I'm thinking of conditions on an inland lake for example.

Great thread, that thing looks bad! Bad Nitro!

:D

[TUFFboat]

The Alison is not a rough water boat simply because of the giant pad, (it turns like nothing I could have ever imagined) The vector (my first boat) has a smaller pad and it is really shorter the 17'1" if you cut off the long beek. The vector has nice Vee walk to it and sucks in the rough. The rough water cat is like a true Vee sliced down the middle. It get its speed from the air lift pushing the hull up insted of the water. But no flat pad. If the little cat is not going fast enough to lift the tunnel floor up high and clear of the water the ride will be rough. If Sho is not always going 75+ (needed for the lift) stay with a Vee. Just deside how much pad you will tolerate. Its all trade offs. Whats your priority? If you have to have a short boat, you can't have a big boat ride.
That nitro looks like a little Express/thunder cat.

[Alan Power]

got it right I think! Put some thought into it and you will get a good boat, its all about R&D.

:confused: I think I've lost you on the rough water bit, I was just saying that for a 15' cat and a 15' V, they will both suffer just as much in the rough.
Were you saying you would prefere a v in the rough or a cat?

I do like that nitro!

[sho305]

I'm saying I see people race(weekend pleasure racing) on a choppy lake and the vee is bouncing all around sideways like mine will, and the tunnel is pretty stable. You can trim down with the vee if you have good power, but the cat is not triming down much. Is that not right? No offense, it just looks that way. I have not been in a fast cat/tunnel.

Where I boat I rarely see smooth water and no wakes, so I figure I'd rather have something to run in that. Over 18' will not fit a garage, and gets so big and big in power too. I don't need to go 100....yet.;) I'd like to get the 80s and work it from there. Been into the big vee stuff, and I don't want that big a boat around now either. At 17-18' I can get into thousands of lakes here real easy, and I want to see a few of them. I can also fit 4 in there if I have company. Unless you are saying they ride poorly under 75? I will not be able to go that fast all the time, some lakes are not that big here, and you gotta turn around. I think my lake is well under 200 acres. Have to run it there too.:confused:

[Alan Power]

much for comfort I just want to know if it is possible/sane to run a 15' cat in that kind of water. If the tunnel isn't swamped it will still run, right? My main priorities are 15' & fast, I still think the cat on comparable size. What's your opinion?

[sho305]

I would guess you will, until it gets so rough you stick a wave. I hear that is worse in a cat than a vee:eek: I think swells are a bigger problem, and chop is ok. I don't intend on going there:) I just want to have some go-fast fun....and sliding by a vee in some chop would be the ticket:p whooshhh!

If you are in big water, you might check the bow height closely. That is my question about the nitro, you see the bow is not that high, or is it because you can't run it in that big of water anyway? The vee will throw you out of the seat, but tends to stay upright if you can hang on. Been there, done that.

[TUFFboat]

When asked about which is better I always think in terms of maximum performance (fast as you can go), but as sho reminds me, not everyone is going 100% 'on' all the time. In fact most of the time you would be cruising at 70% effort. So Alans little tunnel would have a different ride at 50-60mph with 3 people than would a little Vee. The big flat surface of the tunnel bottom would bag off every wave. that dosent mean its slower, just more abusive. Thats why I would guess that a center pod would be good in that little thing, more slow speed lift, less tunnel bagging.
That low height front sponson thing I would guess means they are not going out in the rough. When Peter made the 40 Skater they made the bow high and stumpy to deal with european rough water. You may consider Sho's point on that, Alan.

[sho305]

Most of the time, I run in a chop just over a foot or less. So this could still work nice for me. I would just have to watch the wakes at mid speeds then. With my vee, if you trim it for some speed it just goes airborne on a wake. When I go faster it really goes up! Then you get all the wobble when you hit them at an angle too.

Thanks for the comments TUFFboat!

[Alan Power]

That's a very good point guys, that has definately given me something to think about. Might build the mold with a pod in, try one with a pod and one without. It wouldn't be hard to blank off the pod in the mold, than to build the mold without a pod and retool.

TUFFboat; saw the pictures of tibs firewalker has posted, the TUFF 21 looks great, have you changed much from the original boat? How's the show going?
Thanks Alan:D

[TUFFboat]

That picture from firewalker is sort of my test boat, there is no real TUFF 21 yet. Its still in tooling. This thread has been fun because it has made me think about my own project more thorouhly.
Be sure to show us pictures as it goes.
Good luck guys.

[Alan Power]

My project is still in the design process, I would like to get all the info together before I start the final design process. Jim Russell's book, sectrets of tunnel boat design, I ordered arived today so that should help a lot. I will keep you posted on my progress and post pics as soon as I have something to take them of!:D

Thanks for all the help and keep us updated on the TUFF 21.
Regards Alan.

[Jimboat]

sho305 - If interested, the Elements of Boat Strength for Builders, Designers and Owners, by Dave Gerbook (http://www.aeromarineresearch.com/boating%20books%20discounts.html) is available on our website (http://www.aeromarineresearch.com/boating%20books%20discounts.html).

Alan - Glad you got the book. STBD book (http://www.aeromarineresearch.com/stbd2.html) will outline the balance analysis that TUFFboat was talking about. If you like, you can send me some of the details on your new tunnel design concept, and I'd be happy to run the design with the TBDP software for performance analysis. TUFFboat (on this thread) is 'bang-on' with recommendations to pay close attention to balance of the hull. This dynamic balance is important to consider at all speeds that you'll be running (not just a static weight balance), since the dynamic balance of the hull changes with every velocity. TBDP can show where Center of Pressure is at all speeds, and how it affects dynamic balance. Let me know, and I'll be happy to help if I can.

Spray Rails - most always are a benefit. Unlike step design and placement (which are very tricky to place and design properly), spray rails will work in most all applications - even if the placement isn't perfect. Inside and outboard rails usually a benefit. Reduction of hydrodynamic drag is biggest benefit on inboard spray rails; Outboard rails also provide small amount of lift if properly placed (height).

- Saw 2 of TUFFboat's prototype Tuff '21's at the boat show....what a beautiful boat. I'll post some pics soon on our web site. Can't wait to see the first boats out of the molds!

[Alan Power]

Thanks, the book is great. I meant to write you an e-mail to confirm I got it, but was distracted!!!
To be honest I haven't put it down since I got it, will recommend it to anyone.:cool:
It would be great if you could run the parameters through the TBD software, what info do you need to run the program?

I saw a few shots of TUFFboat's boat on here, looks super, both himself and Sho have great on this thread, thanks guy's!

Thanks again Jim, I will e-mail you some info on the boat later, once again the book is GREAT, well worth it.
Regards Alan.

[sho305]

I guess I gotta get a book too now.....this is way too much fun!:D