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Nautical 5

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Joined
Oct 11, 2021
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5
Hello, i am looking at a Mainship 30 Pilot with a Cummins 240. It topped out around 15 knots at around 2700 rpm’s. Wondering if these readings sound accurate for this boat? Thanks in advance.
 
Welcome aboard TF. There are many prior / current MS owners here.
I'm not intimately familiar with that boat / engine but it seems reasonable. You will likely hear from a Pilot owner with better info.
You should be able to look up that engine to see what WOT should be. Whether it reaches WOT is one worthwhile data point.
 
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Welcome aboard. What Cummins is in it? My 450s top out at 2600RPMs.
 
I think you may have the Yanmar 4LH 240, a 4 cylinder engine, in that boat. 15 kts sounds about right. But 2700 rpm is way too low if it is that engine. Should be 3,300 at wot.

Could it be that you really do have a 6 cylinder Cummins? The 6BT? 2700 rpm at wot would make sense for that engine. Never heard it referred to as 240. Usually 210 or 220 hp.

David
 
Attached is the sea trial data from my 2001 MS30 with a Cummins 6BT220 which I owned for 10 years or so.


The engine turns a 1 1/2 inch stainless steel shaft through a TWIN DISC 2.39:1 ratio reduction gear terminating in a “22RH27”, “H-CUP” four (4) bladed propeller.


Great boats and power plant. Hope this helps.

Cheers
 

Attachments

  • MS30 Seatrial Data.pdf
    261.3 KB · Views: 17
I think you may have the Yanmar 4LH 240, a 4 cylinder engine, in that boat. 15 kts sounds about right. But 2700 rpm is way too low if it is that engine. Should be 3,300 at wot.

Could it be that you really do have a 6 cylinder Cummins? The 6BT? 2700 rpm at wot would make sense for that engine. Never heard it referred to as 240. Usually 210 or 220 hp.

David

Yes it is a 6 cylinder Cummins , just curious, I’ve been reading cruising speed 16/17 knots for that boat but maybe those figures referred to one with a yanmar.
 
Here's a review of the Pilot 30 with a Yanmar. The last page shows a table that looks about right to me, but contradicts the speed they mention cruising at early in the article. (Also note they mix knots and MPH) My Pilot 31 with a 315 Yanmar will cruise at 15-17 knots and max out around 23. It seems comfortable around 15 and I don't often push it much harder. It would be a worthwhile test to see if you hit max rated RPM at WOT. Mine does, but it's a different boat and engine than yours.

http://dicksimonyachts.com/Brochures/Mainship/30-Pilot/30review.pdf
 
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There are many iterations of a 6 cylinder Cummins marine engine, you need to get the model number off the tag that’s on the gear cover right forward of the injector pump.
That tag should also state rpms.
 

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