Defever 51 POC - Repower - Diesel, Hybrid?

[King Zarkon]

Hello Everyone!

In the summertime I purchased a DeFever 51 POC. She needs some love from a power perspective.

She is running dual Cat 3108 TA's with just under 10,000 hrs each. A mechanic has told me that the injection pumps need to be replaced; that they are too far gone to be rebuilt.

So this leaves me the following question:

Should I just be thinking about a repower? I have done some reading that tells me perhaps the 3208TAs won't be good for much longer.

I've been considering the following options:

1) Repower with new diesel engines. If this is the right way to go, I would love some recommendations, as I am new to the world of diesel engines.

2) Hybrid Setup - I have been looking into some electric motor options. Maybe this is a crazy idea with this size of boat and hull shape, but I am going to try and do some math to see if an electric setup with my 15kw generator used as a range extender, similar to my BMW i3 car. Most readily available marine electric motors would be desperately underpowered, but the new Ford crate Eluminator motors put out 285hp 315tq for a very reasonable price. I'm not sure anyone has tried this approach as of yet, but I can't think of an obvious reason to rule it out.

I've been a long time lurker on the forum and am really excited to hear any suggestions you all might have on the matter.

[TrentePieds]

Hello Zarkon and thanks for looking in :-)

You don't seem to be getting any takers. that prolly 'cause most of us here are rag wavers and get along with far less power that a Cat 3208 produces.

We have a sister forum:

https://www.socialknowledge.com/comm...trawler-forum/

Try going there. That where the serious trawler people hang out.

Best of luck :-)!

TrentePieds

[King Zarkon]

Thank you I shall do just that

[ranger58sb]

Originally Posted by King Zarkon

She is running dual Cat 3108 TA's with just under 10,000 hrs each. A mechanic has told me that the injection pumps need to be replaced; that they are too far gone to be rebuilt.

So this leaves me the following question:

Should I just be thinking about a repower? I have done some reading that tells me perhaps the 3208TAs won't be good for much longer.

I don't follow Cats all that much, but haven't seen anything suggesting impending 3028 vaporization.

Just rebuild the 3208s and run them for another 10K hours.

You can read about engines on boatdiesel.com; well worth the subscription. Yes, check out trawlerforum.com.

-Chris

[King Zarkon]

Excellent, thank you for the advice! I had heard that the turbo/aftercooled model might not be worth rebuilding at those hours, but there's a lot of advice out there!

[skipperpete]

Originally Posted by King Zarkon

Excellent, thank you for the advice! I had heard that the turbo/aftercooled model might not be worth rebuilding at those hours, but there's a lot of advice out there!

They’re a fairly simple engine to rebuild but the parts are expensive and if the machinery has been poorly maintained the parts list could be extensive. The injector pump is not a complex rebuild but with 8 of everything, the cost can quickly reach uncomfortable levels. The main problem though is what do you replace them with if you choose to do a repower, those 3208’s are fairly short and compact for the horsepower they put out so usually an in-line six of any breed won’t fit into the Defever engine space.
Suggest you contact Cat and ask about their “REMAN” engine option, these are factory rebuilds, I’ve bought reman turbo’s and other components from them but never a complete engine.

[rslifkin]

Originally Posted by skipperpete

They’re a fairly simple engine to rebuild but the parts are expensive and if the machinery has been poorly maintained the parts list could be extensive. The injector pump is not a complex rebuild but with 8 of everything, the cost can quickly reach uncomfortable levels. The main problem though is what do you replace them with if you choose to do a repower, those 3208’s are fairly short and compact for the horsepower they put out so usually an in-line six of any breed won’t fit into the Defever engine space.
Suggest you contact Cat and ask about their “REMAN” engine option, these are factory rebuilds, I’ve bought reman turbo’s and other components from them but never a complete engine.

That might be the first time I've heard a 3208 called compact! Being pretty large displacement for their power output, they're not exactly a small (or lightweight) engine. The V block design does keep the length a little shorter than many I6s though.



Comparing to a JD6068, for example, the 3208 is about 8 inches shorter in length, but 3 inches taller and 4 inches wider. Weight is pretty close between the 2 (unless we're talking about the 435hp version of the 3208, which is heavier).



Realistically, it's worth assessing what shape the 3208s are in and deciding what it's worth putting into them. Operationally, my only complaint with 3208s would be that they're one of the least sociable engines I've seen in a marina (worse than a 2 stroke Detroit) due to the rather significant amount of smoke they throw on a cold start (and it continues until you're underway for a few minutes and get enough heat into the cylinders).

[sailingharry]

Your idea of hybrid is an absolute non starter for this application.

In the sailboat world, there is a fierce debate about the viability of hybrid and/or all electric. That is an entirely different scenario, where the proponents argue that you only need enough power for a few miles in and out of the marina, and slowing down to four or five knots to improve range is considered acceptable. They also point out that when the conditions are poor for motoring, they can sail. Also, the extremely small power demand coupled with extremely low use hours allows at least some support from solar charging. Your use case is entirely different!

Your 15 KW "range extender" is good for less than 20 horsepower to the shaft. That would probably limit you to a boat speed in the five to six knot range, maybe less, in ideal conditions. While that 235 HP motor sounds nice, enough battery to run that for even 10 minutes would be astoundingly expensive (very rough calculations indicate that at full power, the battery would cost about $1,000 per minute of runtime). And the shore power cord to support recharging it in any reasonable length of time would be unavailable at most marinas.

Stick with diesel, it is the only viable option for a cruising powerboat of your size.