9.8 high torque question

[Yooks]

Hello. I'm building an 11' garvey-style skiff. The boat will weigh around 100lbs and have a 10 degree deadrise. Based on user experience, it sounds like a 10 hp outboard will plane the boat with two adults and one small child. I'd prefer to be able to plane with a slightly larger load (2 adults and 2 medium size kids.)*

I'm looking at the Tohatsu 9.8 with a 20" shaft. Will the "high thrust" prop (as i understand it there are two different 4-blade props, a 7 pitch and a 5 pitch) on a tohatsu 9.8 help get the boat up on plane? I'm not too worried about sacrificing top end speed as my sons will some day be driving the boat and I don't want it to go too fast with a light load anyway. I just want to get out of the hole and on plane.*

Alternatively, would you suggest I move down in pitch with a standard 3 blade prop to a 6 pitch?

I'd prefer to stick with the 9.8 rather than move up to the 15 due to weight considerations.

Can anyone tell me what the speed difference might be between the standard prop and the ht?

Thanks,
j*

 

[pvanv]

The HT props are typically specified for heavy displacement, such as a sailboat or barge. They have however been used successfully on RIB setups as well. They are intended for slow speeds. They do shovel a lot of water at slow speeds. If you want to try one on such a light boat, I would try the 7 pitch. I have a 5 pitch on my sailboat, and achieve 6,000 RPM at 5 knots. Obviously there is some slippage, but I would expect your light boat would over-rev with the 5 pitch.