2hp speed challenge

[scruff]

If I may set the scene - the (Sailing - sorry!) boat is now out of the water and winterised, my current job has me working from home with the potential for some non work tinker time.

I was brining the accoutrements back in the car, the waft of the 2hp, 2 stoke outboard filling the cabin - I wondered how fast could I make that go...? Previously whilst strapped to the back of a 2.3m, soft floor tender I got the average speed - over a 5 min timed run of 8.3km/h carrying two people.

Where would one start to design & build over a winter a punt / dory to see if I can get the outboard pushing a faster average speed?

To set ground rules, this is firmly in the playing category so spend has to be well under 4 figures (pref low 3 figures really) - think more b&q ply than carbon composites & the "boat" has to be able to carry one person.

Thanks

 

[BruceK]

I dont think you will beat that speed unless you put in a canoe.

edit : or a catamaran

 

[LittleSister]

Unlike BruceK, I think you should be able to do a lot better that a flubber, but I agree a canoe or catamaran (or trimaran) type hull worth considering.

Length, light weight, smooth surface, low profile/lack of windage, and (to cut a long story short, and assuming monuhull) as little lateral form stability as you can get away with, would seem to be things to factor in.

Someone I met had put a 5hp outboard on the back of a Laser hull, and that went rather briskly!

 

[Dino]

It’s all about foiling in the high performance sailing world these days...
Here’s an interesting project https://youtu.be/t3eX507Xi_I

This is interesting with a 5hp https://youtu.be/SFZwUxEbxW0

 

[QBhoy]

If inflatables are allowed, I can manage 12 mph on the gps phone app with a suzumar 2.25 (I think) airdeck and a Suzuki 2.2 (great engine but the lack of tell tale a constant worry)

 

[TQA]

Waterline length is your friend. Build something long and skinny and it should reach max displacement speed. Generally agreed to be 1.4 x square root of waterline.

 

[Firefly625]

google hydroplane!

let plywood be your friend

in fact google Mini Hydroplane for your project, something like what I have pictured (Bobcat 8) a good start. Simple, and would come in under your budget.. so long as you are handy in the carpentry department.

 

[Firefly625]

or...

I wonder how fast it would go on the back of this

https://www.ebay.co.uk/itm/Boat-jet...h=item3d7642ce54:g:PbwAAOSwBHJbuNxg:rk:4:pf:0

simple project....

 

[dunedin]

It’s all about foiling in the high performance sailing world these days...
Here’s an interesting project https://youtu.be/t3eX507Xi_I

This is interesting with a 5hp https://youtu.be/SFZwUxEbxW0

Agree. For a project to keep you interested it has to be foiling (but not as heavy as the overweight one in the video).

Anything else is so last century

 

[Seastoke]

It won’t be a a Honda 2.3 that’s for sure ,it’s like a boys moped all noise and no balls