Silly Seville
Senior Chief Petty Officer
- Joined
- Dec 5, 2009
- Messages
- 798
Hey Guys,
I'm actually pretty well versed in this matter, but wanted some opinions.
Here's the situation.
My Sundancer has a very ratty outdrive that has terrible electrolysis related corrosion and is probably nearing the end of its serviceable life. I was going to buy an SEI drive of the correct ratio (1.5 in my case) and call it done, but I happened upon a deal I couldn't pass up. I recently bought a complete Alpha 1 for pennies that is in near new condition, thinking I would just use the lower half. It came from a V-6 boat and I have confirmed it's a 1.84 gearset.
Now to my question: Can I make reliable use of this gearing with my V-8?
Here are some facts. Boat weighs 6000 lbs. with 4 people and fully equipped for a weekend. I currently have a never installed 15 pitch, 3 blade aluminum prop. The old one is toast. This boat is a cruiser, not a racer, so it will never see WOT...not even to get on plane. I am very gentle with the throttle and have big 'ol hydraulic tabs. I know that running 1.84 gears in place of the stock 1.5's will cause the engine to potentially over rev.
Can I compensate for the different gear ratio of the V-6 outdrive by increasing my prop pitch an equivalent amount? For example, Sea Ray suggests at largest, a 15 pitch prop with the small block 350 on my boat for quicker planing performance; but then top end suffers as maximum rpm will be hit very quickly.
Conversely, with a 19 pitch, it would be a dog getting on plane when using the standard 1.5 gears, but would have much greater top speed if running at or near WOT...which I don't want to do. I prefer to use cruise rpm of 3200-3300.
Would using a 17 pitch prop be the perfect compromise with this setup; or will 300 horsepower with the 1.84 gearing be able to spin a 19 pitch and still be able to stay on plane at 3300rpm?
Hope you engineering types love to perform these equations!
Thanks for any insight folks. I hate to buy props just to "try them out." :facepalm:
I'm actually pretty well versed in this matter, but wanted some opinions.
Here's the situation.
My Sundancer has a very ratty outdrive that has terrible electrolysis related corrosion and is probably nearing the end of its serviceable life. I was going to buy an SEI drive of the correct ratio (1.5 in my case) and call it done, but I happened upon a deal I couldn't pass up. I recently bought a complete Alpha 1 for pennies that is in near new condition, thinking I would just use the lower half. It came from a V-6 boat and I have confirmed it's a 1.84 gearset.
Now to my question: Can I make reliable use of this gearing with my V-8?
Here are some facts. Boat weighs 6000 lbs. with 4 people and fully equipped for a weekend. I currently have a never installed 15 pitch, 3 blade aluminum prop. The old one is toast. This boat is a cruiser, not a racer, so it will never see WOT...not even to get on plane. I am very gentle with the throttle and have big 'ol hydraulic tabs. I know that running 1.84 gears in place of the stock 1.5's will cause the engine to potentially over rev.
Can I compensate for the different gear ratio of the V-6 outdrive by increasing my prop pitch an equivalent amount? For example, Sea Ray suggests at largest, a 15 pitch prop with the small block 350 on my boat for quicker planing performance; but then top end suffers as maximum rpm will be hit very quickly.
Conversely, with a 19 pitch, it would be a dog getting on plane when using the standard 1.5 gears, but would have much greater top speed if running at or near WOT...which I don't want to do. I prefer to use cruise rpm of 3200-3300.
Would using a 17 pitch prop be the perfect compromise with this setup; or will 300 horsepower with the 1.84 gearing be able to spin a 19 pitch and still be able to stay on plane at 3300rpm?
Hope you engineering types love to perform these equations!
Thanks for any insight folks. I hate to buy props just to "try them out." :facepalm:
