Rebuild vs Repower

[EngNate]

I agree with David M, and all this seems premature prior to a complete evaluation of the existing engines. ( No mention of hours on them) With the non OEM engines the boat won't market well except to a buyer with the same idea in mind.

 

[Nomad Willy]

One of the biggest advantages to re-powering is that you have the wonderful opportunity to change the power output. There are so many rec trawlers that are seriously over powered and re that “problem” changing engines is the only way to really address the problem.

 

[rslifkin]

One of the biggest advantages to re-powering is that you have the wonderful opportunity to change the power output. There are so many rec trawlers that are seriously over powered and re that “problem” changing engines is the only way to really address the problem.

I agree that there are plenty of "trawlers" out there that are poorly powered, but for many of them, they're just as much underpowered as they are overpowered. Many have hulls that could plane given enough power (and the matching small rudders, etc.), but they're not powered to run more than a few kts above hull speed. Yet they're overpowered for running at displacement speeds.


The Mainship 430 isn't in that category, however, as it's capable of planing and has enough power installed to do so out of the box. It may be overpowered for running slow, but it wasn't really designed to only go slow (it's a noticeably different hull design than the 350/390 and 400, all of which are mostly meant to go slow, even though they can sorta plane if enough power is installed).

 

[timb7734]

Let’s see:You don’t know what the cost of rebuilding the engines really is as you have no estimates, but you are willing to significantly devalue the vessel with an engine change where you also do not know the installation cost of the ancillary equipment, all for the satisfaction of turning a semi displacement design into a severely underpowered “trawler” for totally illusory fuel savings?
I owned a trawler for ten years equipped with 74 h.p. Yanmar engines and it did 3.5 mpg at 8 knots through thick and thin. I now have a Krogen Express with 440 h.p. Yanmars that will do 3 mpg at the same speed, but also go 16 knots all day.

 

[JoeApicella]

You missed something. I put 3,000 hours on a 2005 Mainship 430 and averaged 2mpg. That's 4gph at 8 knots, 1400 rpm with occasional periods of 2800 rpm with Yanmar 440's.
I had a 370 in my Mainship 400T, 2 440's in my 2005 430, and 2 449's in my Pilot 43. They never missed a beat in 10 years of cruising roughly 6,000 hours total.