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Beta Marine Repower Solutions -> Beta Marine Engines -> Size engine and prop for Motorsailer (Finn 35)
Post Info TOPIC: Size engine and prop for Motorsailer (Finn 35)
Stanley


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Size engine and prop for Motorsailer (Finn 35)
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Hello and welcome to the forum,

I have checked the link that you supplied with this one http://www.western-horizon.co.uk/boat_details.php?boat_id=286

Personally I think that a 75HP, low RPM, high torque engine is overkill on this boat unless you are wanting to go into the towing business. I believe that you will get fine performance with the Beta 43 and you will have a gracious reserve of power using the Beta 50 with a transmission ratio of about 2.5:1. This assumes that you can fit a 21" propeller so that you can get the power to the water.

If you currently have a Borg Warner Velvet Drive transmission, I would stay with it because this changes the relationship between the engine beds and the shaft and your labor costs will lower.

The Beta 50 will still give you a bit over 8 Knots and a comfortable 6 to 7 Knot cruise speed with great economy and almost no engine noise and still provide the reserve of power associated with a motor sailor.

Regards, Stanley



-- Edited by Stanley on Friday 31st of May 2013 12:08:31 PM

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finn35


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Looking at Betamarine as an option for a repower.

I have a Finnsailer 35. It's 35 ft long, 14,000 lbs. That 14000 would be unloaded for cruising I suppose. There is quite a bit of tankage for fuel and waterl.. so fully loaded for a trip, I imagine just under 20,000 is a good number to play with.

Sorry.. I don't know anything about the prop on her.  Here are the specs: http://sailboatdata.com/viewrecord.asp?class_id=4412

Original engine from the factory was a 75 HP Perkins. I think that was much more HP than the boat needed.

If I try to match the original factory HP, a Beta 75 would seem to be the choice. But that doesn't seem right. I'm thinking a Beta 50, or even a 43 is suitable. 

Seems many comparable boats are happy with a 43 or 50. On the other hand, the Finnsailer is heavily built. So maybe 75 is the trick.

The engine room is very spacious, so size probably not an issue.

Any thoughts?



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finn35


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Thank you Stanley...your reply is helpful.

This boat is not mine, but it is the same model. http://www.finnsailer35.com/Finnsailer35BottomScrub.htm

The prop apperature is pretty big.

I may dive off the boat this weekend and see what I can find out about the prop.

Thanks.

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