Refit 31 prout Repower advice

[44'cruisingcat]

The Yamaha 9.9 high thrust motors would be a good choice.

[Cadence]

Originally Posted by 44'cruisingcat

Honda did the 28 inch shaft on the BF 20. However I'm pretty sure that motor was never available in the US.

Maybe some one knows if Honda marketed a 15HP high thrust with a 28 inch leg circa 2003 in the US. As I said, I thought that is what I had but could be wrong. It was a sweat engine for an SR31. Made hull speed of 7.5 K at about 2/3 throttle and .75 GPH. Could make 8 and that was probably at a foolish GPH. It's hard to tell in ten minutes.
Speaking to hull speed, Under sail flying an ama she did 17.5 so hull speed didn't apply, my pucker factor did.

[shane malone]

17.5 sounds like a hole lot of fun wow i hope to see 10 in this prout power sailing ��

[Cadence]

Originally Posted by shane malone

17.5 sounds like a hole lot of fun wow i hope to see 10 in this prout power sailing ��

A tri and cat are two different animals.
as I said my pucker factor was up. Never did it or would again. A new to me boat and just the right conditions. You can bet the main sheet wasn't cleated. My young foolish days of 60.

[classicone]

I repowered my 31 Quest 2 years ago with a single long shaft Yamaha 9.9 high thrust (older 9.9-15hp block). Saved 500+ lbs over the old Bukh 20hp diesel with Sillette drive. After much measuring, the extra long shaft was only 3" longer than the long shaft and the long shaft propeller was about in the same place as the Sillette. It did raise the aft end of the boat almost 4". We sail faster, 1 to 1.5 kts faster at the same wind speeds and conditions. Burn about .5 gal an hour at cruise. Anything over 6kts we have a tendency to just dig a hole aft. Have not cavitated once using the existing location.



My Quest was originally molded for an outboard that the factory had covered with a thick stainless plate in order to mount the diesel. Changing over was a simple remove and replace operation with some adjustment of the transom height to facilitate the outboard operation.

I have pics if interested.

[mikedefieslife]

Pics of modded Prouts are always appreciated. They are very different from Catalacs or Geminis and the like when it comes to adding outboard. Their narrow canoe shaped hulls with transom hung rudders really limit the placement of outboards and restrict the separation (for those thinking of going with two engines)

[Cadence]

Originally Posted by classicone

I repowered my 31 Quest 2 years ago with a single long shaft Yamaha 9.9 high thrust (older 9.9-15hp block). Saved 500+ lbs over the old Bukh 20hp diesel with Sillette drive. After much measuring, the extra long shaft was only 3" longer than the long shaft and the long shaft propeller was about in the same place as the Sillette. It did raise the aft end of the boat almost 4". We sail faster, 1 to 1.5 kts faster at the same wind speeds and conditions. Burn about .5 gal an hour at cruise. Anything over 6kts we have a tendency to just dig a hole aft. Have not cavitated once using the existing location.



My Quest was originally molded for an outboard that the factory had covered with a thick stainless plate in order to mount the diesel. Changing over was a simple remove and replace operation with some adjustment of the transom height to facilitate the outboard operation.

I have pics if interested.

Well said.