Seacraft 32. Twin 200 Yamaha 4 strokes!

[Was12]

My dad recently bought a 2000 seacraft 32. Before buying the boat we made sure that the updates were done to it and they were. When he bought it it had twin merc 225's and it ran 44 mph. We already had a set of Yamaha 200's from another boat so we repowered it with them. Every outboard dealer or anyone that knew about the 32 said it was going to be under powered but we figured we test them before getting a pair of bigger motors. The motors ran much better than expected. We have great hole shot and top speed. We are running 48.2 mph top speed and about 35 mph cruising at 4000 RPMs. The boat rides very well with the 200's. We ran in 3 to 5 ft seas from jupiter Fl to Marathon in 5 and a half hours which is about 195 miles. We only burnt about 110 gallons total and ran non stop.

[77SceptreOB]

That sounds good. I too am surprised that those twin 200s could produce that solid performance. Yamaha make a great motor.

[Capt Chuck]

I am wondering if you should lose an engine, I doubt that a single 200 would plane that hull

[Ryan]

Originally Posted by Capt Chuck

I am wondering if you should lose an engine, I doubt that a single 200 would plane that hull

well to be fair Chuck the 225 isnt going to plane it either.

[Was12]

I know that the 225 mercurys didn't push it on plane any better if not worse than the 200s so I know that the a single 225 isn't going to be pushing it. I will have to see what happens when I try to push it up with one engine.

[captbone]

If you have the time and effort to humor me.

Install a Mirage Plus 13pitch prop on one of the engines and I will bet a beer that it will plane and run 32mph+.

People will laugh at me but I certain. 16x13 Mirage Plus on one of the engines will plane off and run. Yes, 200hp on a 32ft Seacraft.

[gofastsandman]

Originally Posted by Was12

I know that the 225 mercurys didn't push it on plane any better if not worse than the 200s so I know that the a single 225 isn't going to be pushing it. I will have to see what happens when I try to push it up with one engine.

Your LU may not like that. Not much solace I know.

[captbone]

Originally Posted by gofastsandman

Your LU may not like that. Not much solace I know.

The lower unit and engine will never know. Since the prop is smaller and allows the engine to rev to 5500 at wot, its the same load as if it had its normal props on it.

An outboard motor doesnt know if it pushing a bassboat at 70mph or a 50ft barge at 7mph if it is propped correctly to hit wot rpm. The size of the propeller adjusts the load on the engine and lower unit.

[gofastsandman]

Originally Posted by captbone

The lower unit and engine will never know. Since the prop is smaller and allows the engine to rev to 5500 at wot, its the same load as if it had its normal props on it.

An outboard motor doesnt know if it pushing a bassboat at 70mph or a 50ft barge at 7mph if it is propped correctly to hit wot rpm. The size of the propeller adjusts the load on the engine and lower unit.

Ummm...

[FishStretcher]

The torque on the the gears will be the same, true. But the force from the higher thrust at lower speed will be resolved in the lower unit bearings. And the motor mounts. I don't design lower units, but I have a suspicion that this is something you can get away with for a time. Or at least get home and then tear down a LU and put new bearings in it. I suspect the gear teeth will be fine.

Just a guess.