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Old 12-10-2018, 09:18 AM   #14
ben2go
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City: Upstate,SC
Vessel Name: Shipoopi
Vessel Model: derilic sailboat
Join Date: May 2012
Posts: 2,884
Quote:
Originally Posted by djmarchand View Post
The PO probably canned the aftercoolers because they were sea water cooled and he didn't need a sea water pump with his dry stack exhaust and radiator cooling.


If so, that means it was originally a 315 or 370 hp sea water aftercooled engine that was cobbled together for genset or marine pump use. Also I am surprised by a 2,600 rpm wot rating. I thought that the after cooled engines were 2,800 or 3,000.


You really do need someone like Tony. It won't be cheap to buy the missing parts: after cooler, r/w pump, exhaust gas injection elbow, etc to put it back into original condition. Promise to buy them from Seaboard (and they won't be any cheaper from any other Cummins dealer) then Tony may do the consulting for free. Don't think about buying Chinese parts.


David
Quote:
Originally Posted by alfamike View Post
The engine you have definitely was run at 1800 rpm as that is the standard generator run speed for 60 Hertz A/C power here in the USA.

As I see more of what your doing, & I run some numbers over here, you definitely need to go with the 10 degree down angle Twin Disc MG-5050A transmission.

It will handle the engine HP as is now or when you up grade it to higher 365 HP neighborhood as well & it is rated for up to 3300 engine rpm.

For your displacement & design & engine I would think a transmission ratio of 1.8 to 1 ratio in the trans would be good for 12 knots at 2600 rpm with some propeller pitch tweaking depending on what you do with the engine & HP available.

Obviously you may go with the engine as it is now, which if not after cooled is actually about 220 HP & later up grade to the higher HP options you may want, at a later date.

And then you could also run all day - 24 / 7 - at 8 knots running in the range of 1600 to 1800 rpm and get great fuel economy.

Let me know if I can help.

Sounds like a fun boat.

Good luck.

Alfa Mike



Thank you both. As soon as we nail down a start date for the build, I will dive deeper into the specifics of the engine and setting it up. Whatever the power rating was as the engine was originally spec'd is how we plan to set it up. The six-cylinder turbo Cummins is the recommended engine. A transmission wasn't mentioned. Now we have that nailed down, I can get some prices and keep rolling with the estimated build cost.
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What a pain in the transom.

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