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Beta Marine Repower Solutions -> Welcome -> Martec
Post Info TOPIC: Martec
my1972ih


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I recently repowered my CAL Cruising 36 with a Beta 38. 

I have a 1:1 velvet drive and a Walter 1.67:1 v-drive. 

Tthe Beta has two alternators, which to me means that the available output horsepower for driving the prop would be reduced because of the second alternator. 

I want to be sure to order the correct prop. 

The boat is 35.5 feet long, with a waterline of 27 ft.  Design specs state 12,000 lbs displacement, but, as a cruiser, we load it down with stuff.  Also, it has a good deal of freeboard.   

I'm considering ordering a Martec elliptical folding prop since there is no shaft break and the velvet drive transmission cannot be locked in gear when the engine is not running.  Do you have a recommendation on diameter and pitch for the Martec prop?  If they provide the recommendation, what useable horsepower should I tell them to assume?



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my1972ih
Stanley


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When you are going with a specialist propeller such as a Martec folding, you are always better off letting the propeller supplier calculate what diameter and pitch you need. This way, if there is an issue with performance, they should attend to any modification.

The engine develops 38HP at 3,600 RPM and your transmission ratio is 1.67:1.
Allow for an extra 2,000 lbs of weight so the boat weight will be 14,000 lbs and the waterline is 27'. The freeboard wont affect the prop calc.

Stanley

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my1972ih


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thanks, Stanley.


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my1972ih
my1972ih


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FYI, I see info in brochures and online which show the 1505 output ratings of 38hp@3600 and 37.5hp@3000.  Why the differences in published data?  Were older 1505's governed at 3000 and newer ones at 3600?  If so, were there changes made to the 3000 engines to get the 3600 engines?



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my1972ih
Stanley


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The changes have come about as a result of the EPA requirements for emissions. The early engines developed 37.5HP at 3,000.
The new engines develop 38HP at 3,600.
There are changes to the combustion changer and to the fuel cam and injection pump to accomplish this.

There is also another new V1505 block which develops 35 HP at 2,800 RPM.

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