Best 10hp and prop for kids hydroplane

[PAR]

Nissan has all the bells a whistles too Michael. How would you like to have your country insulted, maybe you'd feel better knowing all us rich north Americans, just look down our well fed noses, at third world countries like yours. Do you have a dirt floor in your house?

[Submarine Tom]

Matt,

I'm with you all the way on this one. I'd like to build as well, but not this year.

I found this: http://www.popularmechanics.com/outd...oating/1277141

Which could be modified to suit a four stroke (the only way to go in my opinion).

Move the driver, motor and fuel tank forward, if possible, and have some fun.

Surely there is a modern, 4-stroke design out there, we just have to keep on looking.

-Tom

[Yellowjacket]

The "Shingle" isn't a bad boat, but there are others out there that are better.

Remember, the Popular Mechanics small hydros were intended to be built out of an 8' sheet of plywood, and be made in a hurry for not a lot of money. As a result they tend to be a bit short, and if you aren't careful you can stuff them if you hit a big wake and you go up over the first wave and then, as you pitch down on the other side you go under the second wave... Did that as a kid a lot of times and ended up with a lot of stuff floating around in the boat.

For that reason (and lots of others) you should stay away from the Minimax and it's brothers. They were cheap and easy to make, but were pretty much dreadful boats. Things like the transom not wanting to stay connected to the boat and not enough framing in the bottom to keep them from flexing apart are just the start. If you want to do a three pointer, try to get something that is about 10' long as a minimum and for a runabout look at something that is a bit longer than 8' and has some more bow rise and a more pointed front end (something like the FooLing). Wide bow boats tend to catch waves and wakes and, even in pretty protected waters can be pretty wet. My old Yellowjacket was a champion at catching the front square edge on wakes and hosing me down, and my Minimax was just a miserable boat.

While some of these boats are really easy to make, you probably want to do a bit more work and have a lot better boat in the end. Otherwise at the end of the first season it will be on Craigslist and you will be looking for something else.

[Submarine Tom]

Well that's good to know, thanks YellowJ. What Matt and I are really after is some new-age design for a 9.9 4-stroke. Sorry about the thread high-jack Matt, correct me if I'm wrong. I've searched the internet a couple of times now and just can't find one...

-Tom

[michael pierzga]

You have thin skin PAR. The word Bells and Whistles came from an American. I needed a 40 or 50 hp workboat motor, contacted a trusted motor supplier in the US and he recommended Nissan Tohatsu.. Since I have limited experience with NISSAN, Tohatsu I asked why ?..well, first price then quality , then he mentioned their low profile representation in the US and that they dont market a line of speed props, fancy Instrument systems, nor have Evinrude "tug of war" commercials, pro bassmaster product endorsements, Mercury secret " lake X " testing grounds and the other STRAIGHT FROM HIS MOUTH... "Bells and Whistles". !!!!!!!!!!!!!!!!!!!!!!
Par, I can pass on the name of this American Mid Atlantic distributor if you would like to personally heave some of your insulted pride on him . !!! you may even ask him if he lives in a mud crab shack, perhaps you could send him a few bells and whistles for his crab shack ? And do remember...the topic of this thread was a good small motor for a young boys hydro. I suggest you get back on topic .

[Yellowjacket]

Originally Posted by Submarine Tom

Well that's good to know, thanks YellowJ. What Matt and I are really after is some new-age design for a 9.9 4-stroke. Sorry about the thread high-jack Matt, correct me if I'm wrong. I've searched the internet a couple of times now and just can't find one...

-Tom

That's a pretty tall order. Most of the new designs are more horsepower intensive and are pretty limited in usefulness. Back in the 50's and into the 60's outboards were low powered and there were a lot of low powered designs. After that the horsepower wars started and, while the boats got a lot faster, the small low powered end of the hull spectrum pretty much was forgotten. Don't assume that just because these are older plans that the hulls are slow or obsolete, they had a power limitation and the designers were very good at getting the maximum out of what they had.

You can get plans for modern three point hydros, but they are pretty much useless for anything but going around an oval course in smooth water at really high speed. They have been refined for racing, but aren't much good for anything else. For a lake boat you want something that is more forgiving and the kid can enjoy, but won't flip or stuff he he makes a mistake. A pure 3 point hydro is a lot of fun, but for a 10 year old I'd probably put him in a small utility hull. He won't be able to stuff it, it will go 25-30 mph (and 40 or more with a bigger motor) and if he hits a wake the wrong way you won't have to go out and fish him out (and be explaining it to his mother) and take the chance of wrecking a motor if he dunks it while it is running, which can happen with a smaller hydro. With 10 hp or less, you really can't take advantage of three point hull anyway, and if you did it would be going too fast for a 10 year old.

I'd look at the utility boats, the old Class J boats were designed for 10-14 year old kids, and are a lot more forgiving than a 3 pointer. Both Glenn L and Clark Craft have 9' class J runabouts that are a lot of fun for a kid, and can take bigger motors later. Actually the Glen L A/B runabout would even be better since it is a bit longer and you can put on more power later, but it's kind of a dull looking boat.

The Clark Craft OK9 is a Hal Kelly deisgn (Hal Kelly was a master of these small low powered hulls), it's really easy to build since it doesn't have much framing, and would be plenty fast for a kit of any age. It also is a lot more snarky looking if you build it without the front cockpit open and that counts for something too (or you could make a cover for it and take people for rides with it off). The youngster will learn how to handle the boat, have a lot of fun and it is something that he will remember for the rest of his life. The 11 foot Hall Kelly Foo-Ling is a longer version of the same boat, and it's going to be a little more stable if not quite as fast at the OK9 with only 10 hp. It has the potential to handle more power than the OK9 later, so that's probably an advantage. The plans for the Foo-Ling are here:

http://www.boatracingr11.com/Sorense..._classic_b.htm

If I were doing it that's probably what I would do, since it will work just fine with a 10 hp motor, and as he grows you can put a bigger motor on it and it will still be a safe hull with the bigger motor. As with the smaller boat I'd build it with a front cockpit and then you can take him out and do some teaching with him in the front at first and you up there when he takes the wheel.

A more "modern" hull is going to be a V hull with a planing pad, and these take more power. With this low a power you need a good bit of planing area and the V is less efficient. Same thing with a tunnel hull, you really need more power than 10 hp to get them up into the speed range where they need to be to generate the aerodynamic lift for them to work right. Really do you think a kid is going to care if the boat pounds a bit over wakes or if the water is rough. Moreover, if it's that rough he shouldn't be out in it anyway.

Just some thoughts.

[Submarine Tom]

Excellent thoughts Yellow, I really appreciate your efforts.

What concerns me most is the higher weight of a 4-stroke on those older, 2-stroke designs. Also, I want to drive it too and I'm 200 pounds (90 kg)!

I couldn't agree with you more that it's not about going fast but more about FEELING like you're going fast!

-Tom

[Yellowjacket]

Originally Posted by Submarine Tom

Excellent thoughts Yellow, I really appreciate your efforts.

What concerns me most is the higher weight of a 4-stroke on those older, 2-stroke designs. Also, I want to drive it too and I'm 200 pounds (90 kg)!

I couldn't agree with you more that it's not about going fast but more about FEELING like you're going fast!

-Tom

That's another reason for a runabout, with a 9.9 or even better a re-labled 15 it will push you along just fine. The larger planing surface will work a lot better than the skinny planing surface of a three pointer. You can probably use a 115 pound motor and it would be ok on a Foo Ling because that is a bit bigger boat that has a bit more beam and more floation aft. Wouldn't want to put that much motor weight on top of your weight on a 3 pointer or a J class boat. It would be close to swamping. If you do a remote fuel tank you can put that up front and it will help with the weight situation..

The feeling of speed comes from sitting close to the water, the so called go-cart effect. If you can ge your bum an inch or two from the water it will feel plenty fast even at 25 mph.

[MattM]

Thanks for the advice here, I appreciate it. I don't mind at all building an older design. My toys include Donzi Classics, '32 ford hot rods, a '57 Nomad, and some vintage bikes. I love old stuff. I just didn't want to build an old boat and then find out there are much better designs out there. The glen l and clark craft J class boats look great. I think I'll try one of those.

I have built a lot of stuff out of wood, but never a boat. Should I fiberglass it, or will it live w/ a few coats of good paint. I've got automotive urethane, or can use whatever. I am not too concerned about having a show quality boat, just something that will be fun for the boy to build and last for awhile.

thanks again, Matt

[Yellowjacket]

If you build any of these designs and use a heavier motor, beef up the joints where the motorboard meets the transom, and the joints between the transom and the edges or upper decking surfaces. The mass of the motor is the issue here, when you bounce the boat around the motor works back and forth and it beats those joints to death. The heavier motor will make that worse, but if you add some stiffness and epoxy those joints well it will make a world of difference. On all of the boats I had as a kid we ended up reworking those joints and stiffening up the spray rails from the motorboard forward to help keep the boat stiff and strong.

One thing that you should also do is bond everything together with epoxy. That way you can use fewer screws and the boat will actually be stronger. The old glues that these boats used weren't nearly as strong as a modern epoxy.

You should use a 4 or 6 ounce glass cloth and epoxy on the all of the lower surfaces and transom. This will seal the hull and it will last a lot longer. If you aren't going to do that, at very least you need to glass the seams or it will work open and be a mess. If you are using Okoume or ribbon mahogany the 4 ounce will wet out clear and the boat will have a classic look, the 6 ounce is a bit stronger. Use pealply or wax paper or plastic on top of the layup and roll it out and you will save a lot of sanding time. If you just glass it and roll it out without the plastic or wax paper you will have do do a lot of sanding. If you do 4 ounce on the upper surfaces it will be less likely to get dinged up. If I were doing it I'd probably do since it stays nicer than if it was just varinshed.

Do a search on glassing and you will see some of the techniques that are used, and Par can probably chime in on what epoxy to use and what techniques save you a lot of time and effort.

[Ramona]

Originally Posted by michael pierzga

Get it... simple ,lightweight two stroke and Nissan is a good product. Seems every poor fisherman in the world runs a Nissan. Not so popular in North America because folks are rich and can aford all the bells and whistles offered thru the big name producers.

They are called Nissans in America. They are Tohatsu's in reality. Small Mercury 2 strokes are rebadged Tohatsu's as well. Do a search on Utube for examples.