To all 3-pointer experts.

Howdy!

I am in the process of building an all aluminum 3-pointer.
The hull is 6" x 30" x 1 1/2" deep.
The sponsons are 2" x 6" x 1 1/2" deep.
It will be powered by an Enya .40 puller prop.
Questions:
(1) Approximately what would the ideal distance be between center of the hull and center of the sponson?
Is there some kind of formula to go by?
(2) How much would the sponsons extend forward of the hull? (bow of sponson to bow of hull)

I still have a lot of welding to do to complete the hull and sponsons, but I'm thinking ahead a little and want to be ready for the assembly, which I'm thinking next week sometime.

I have the sponsons all welded by I don't have them with me to photo but this is the basic drawing, and a photo of the hull. ( Before the deck ).

You notice the aluminum is "diamond plate" Thats because it's all salvage material (free) I think the thickness is .050.
It will be on the light side...!

Thanks for your input.
Sirwalter (Walt)

sirwalter,

I am not a 3-pointer expert so what I am about to say is an opinion.

I think the sponsons are too small, they just seem to be tiny compared with the main hull on the drawing. Is the drawing to scale?
Also do the diamonds on the plate show through to the "smooth" side? If they do, then you might want to sand them smooth because the bumpyness might have an effect on performance.

Otherwise that looks real good so far. I cannot wait to see it all together and running. I will be waiting for vids.[8D]

i agree

What gage is the aluminum? Looks pritty thick. You'll be hard presed to get any real performance out of a .40 size boat out of aluminum. The other thing you need to consider is radio glitching with metal. It's been done without glitching but you have to take precautions. As far as performance with an aluminum hull, that can be done too, but on a larger scale. A guy could make his formers say out of 18-22 gage aluminum using I-beem construction and using lightning holes. Then skin it with VERRY VERRY thin aluminum like a pop can is made out of. Then you could exced the strength to weight ratio of the usual miterials used. (bulsa, ply, fiberglass, ect) To do this you'd need to build this around a 1.00 ci. motor or larger and not the cheepies eather. Most plane 1.00 ci. motors run about 3-5 hp stock. You need something outrageously powerfull like a motor that'll run like 40-60% nitro ($$$) with a turbo or something like this;
http://www.geocities.com/ramair1968/...ito.html?20073
(also $$$).
The point is, to build and get performance with aluminum you need to get a high power to weight ratio and it's hard to do on a small scale.
Shawn