what power for raft

What would the best power for a 10 ft raf
Raft has a narrow width .small place for cover at front .
Would a small 9.5 go outboard be enough or would more power be needed.have v front for bow

 

2.5hp is enough..

 

I forgot to add in . Has to enough for around 8 knots

 

8 Knots on a raft means you'll need to push this thing at full plane speeds. This requires power, lots of it and, preferably a hull shape well suited to 2.8 to 3.0 S/L ratios.

Without an idea of the raft shape, weights, and other appropriate information, such as CG location, any engine estimates would be clear blue guesses.

For the most part, a small engine will only get you to displacement speeds, which assuming you have a 10' LWL, would at best be in the 4 knot range. Considering it's a raft, likely quite bluff bowed, with questionable trim, less than this should be expected.

Post some pictures of what you have.

 

If it is powered, is it still a raft?

 

Michael; you must give us more information about your "raft". We may have a language problem wherin a raft might be a hydroplane or it might be a few logs tied together or something in between. Post a picture if you can.

 

It has a v bow , sloped sides that slope into a flat bottom. Ill post the design . 10ft long 5ft wide . Forward step down small room

 

These are the designs

 

Not a raft.. a barge perhaps..
Nevertheless not going to rise my hp recommendation..

 

Forget it again..

 

Would 9.5 hp be enough for speed

 

A bar napkin sketch presents poorly, to say the least. No section view, no weight study, no concept of hull volume necessary for the anticipated loads, etc. If you want folks to take you seriously, you'll need to make a serious attempt, at defining the shapes and volumes, you have in mind. It doesn't have to be dead nuts accurate, but please, you can't expect much positive retort from this type of presentation.

 

Is the "small room" for a leprechaun, Michael ? Gonna be mighty cramped in there ! What you have in mind is more accurately described as a dinghy.

 

The small room is mainly for gear or if it rains .

 

Michael; please refrain from designing your own boat. If I can interpret what you have drawn, you have a three piece bottom that will not go together well. If you manage to build it that way it will have some hard corners right where they must not be.

Buy a set of plans for a simple flat bottomed dinghy of about the size that you have shown. . Build it. A 9.9 HP outboard of almost any kind will drive an intelligenty designed little boat 20 MPH and more. Eight Hp will get you well past your 8 knot target unless you load it heavily. I would not even venture a guess about what you would need for the awful boat that you have drawn. Do yourself a huge favor, buy a set of professionally done plans.

All the forum members do wish to be helpful so we are usually honest with our remarks. No offense is intended when I, or we, tell you that you do not know nearly enough to design your own boat.