Best tiny wood hydroplane to build w/ 10 yr old son.

[MattM]

I posted this on the wooden boat construction section, but didn't get a lot of response, so I'll ask the question here.

My ten year old son and I would like to build a small hydroplane for him over the Christmas break. I have great memories as a kid playing around with some friends hydros. We live on a river and he's excited about building and driving it in the summer. I've surfed around and it appears that all the little (8') hydro plans are from the 60's and maybe 70's. It appears that the Mini Most would be a relatively easy build and perform well. Until he's 16 he can only drive a 10 hp boat. Is this a good boat, and will it run w/ 10 Hp? Is there really nothing newer or better than a 40 year old design? A little runabout semi V seems like it would be more versatile, but I can't seem to find any designs. Does anybody have any experience with this? I would guess or hope that there has been some design progress here in the last 40 years, but maybe w/ jet skis and video games people just aren't doing this anymore.

thanks, Matt

[Bruce46]

given your situation and its restrictions many of the older designs from Clark Craft, GlenL or http://www.bateau.com/studyplans/RB1....htm?prod=RB12 would be better then a true hydro. True hydros are tricky to drive and not for a beginner. You might want to check out, http://www.svensons.com/boats/?f=HydroPlanes/spitfire/SpitFire_1.jpg> Yes I know it is an old design but the older designs were created with small eninges in mind. In a boat like these it will feel like you are going fast without gettng into the realm of dangerous speeds.
I used to race a very light weight 13' boat with a 50 hp and it was way too fast for a novice. Good luck and have fun with a great father / son project.

[tom28571]

Personally, I think the B Utility Class would be the most suitable boat for this job. Plenty fast, more seaworthy and much less finicky than a three point hydro or minimum size craft like the Minimax or its brothers. Plans and kits are available.

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

[Submarine Tom]

" Is there really nothing newer or better than a 40 year old design? "

-Tom

[tom28571]

Originally Posted by Submarine Tom

" Is there really nothing newer or better than a 40 year old design? "

-Tom

Within that Class, probably not. No stock <20 cu inch motors have come along that beats what was available then and are still the best available. Within the Class rules, those boats were, and still are, very good. Try your hand at beating them if you like. In fact, the overall interest, participation and competitiveness of small boat racing was way better then than now. Probably different in the larger and unlimited classes where power has gone well ahead and hull design has had to change to keep up.

[Bruce46]

Tom, These may be old designs, however, for a novice they would be a good starting point. Be aware that people missuse the term hydro or hydroplane. As I stated earlier a hydro or even a tunnel hull is not the place to start. It is best to start with the basics.

[cthippo]

Originally Posted by Bruce46

Tom, These may be old designs, however, for a novice they would be a good starting point. Be aware that people missuse the term hydro or hydroplane. As I stated earlier a hydro or even a tunnel hull is not the place to start. It is best to start with the basics.

Could you define those for me? I thought a hydroplane was pretty much any hull and power combination designed to bounce over the top of rather than displace water?

[Bruce46]

Coming from a racing background there is a huge difference between a hydroplane and a planing hull. A planing hull is lifted by hydrodynamic forces until those forces lift the mostly out the water, a hydroplane, however, is skimming over the water in ground effect, ie: riding on a cushion of air.

The basic principle of the hull design of most hydroplanes has remained much the same since the beginning of the sport: two sponsons in front, one on either side of the bow; behind the wide bow, is a narrower, mostly rectangular section housing the driver, engine, and steering equipment. The aft part of the vessel is supported, in the water, by the lower half of the propeller, which is designed to operate like that. The goal is to keep as little of the boat as possible from touching the water, since water gives more drag than air.

One of the few significant attempts at a radically different design was referred to as Canard. It reversed the width properties, having a very narrow bow that only touched the water in one place, and two small outrigger sponsons in the back.

Early hydroplanes had mostly straight lines and flat surfaces, other than the uniformly curved bow and sponsons. The curved bow was eventually replaced by what is known as a pickle fork bow, where a space is left between the front few feet of the sponsons. Also, the centered single, vertical tail (similar to the ones on most modern airplanes) was gradually replaced by a horizontal stabilizer supported by vertical tails on either side of the boat. Later, as fine-tuning the aerodynamics became more important, the bottoms of the main hull have subtle curves to give the best lift.

[tom28571]

Originally Posted by cthippo

Could you define those for me? I thought a hydroplane was pretty much any hull and power combination designed to bounce over the top of rather than displace water?

You are correct, but meanings change over time and loose their original intent. Useless to argue about such things as its a total waste of time. Hydro = related to water. Planing = skimming mostly on top of the water. These we can generally agree on although just what constitutes planing always gets a lot of discussion.