Trojan Boat Forum

LandVF36 wrote:So, those of you that have converted, what did you spend again? I sent a note to Mercruiser last week after seeing and add for their new marine diesels somewhere. Thle add claimed to have new options for dimensionally equiv models to replace my GM 454s. The new engine was a common rail 6 cyl model, gears and guages ..... $79K.

I love my boat, a but I can buy a lot of gas and parts for the old blocks before I'm going to burn through that kind of fuel.

Is this price what others have spent on a new swap to Diesel?

Conversion costs can vary wildly. Dropping the boat off at a reputable marine mechanic to have the latest and greatest engines installed and approaching the project with an open checkbook- replace everything -mentality, could easily top 80-100K for new twins with all support systems. Thats one extreme.

I've also heard of DIY guys buying older running diesel takeouts with gears- then selling thier gas engines and getting out of the whole project for under 10K. That's the other extreme.

Most guys are somewhere in the middle of that range and exactly where will depend heavily on the owner and the boat. The largest factor IMHO- depends on wether the owner prefers to hold a wrench or a pen.

There's a lot of logic in the arguement that a costly conversion is difficult to justify based on fuel savings alone. But I can tell you phsycologically- and mathematically- the fuel savings are significant.

When I had gas engines- I had flow scans so I knew exactly what I was burning... it was around 23 GPH @ 17 knots. This is when gas was 2.25/gal so it was costing me $51.75 per hour to run the boat or $3.04 per nautical mile. At the high point, gas was $4.25/gal so that would have cost $97.75 per hour or $5.75 per nautical mile.

At it's peak, I paid $3.79/gal for marine diesel. My boat now cruises @ 20 knots burning 14 GPH. That equates to $53.06 per hour to run the boat or $2.63 per nautical mile at the peak. Thats still cheaper (per mile) at diesels peak compared to gas at it's low point when I bought the boat. Diesel is now is round $2.59/gal so my fuel costs are $36.26/hour and $1.81 per nautical mile.

Yes- it will take years to save what I spent on the conversion but, the visits to the fuel dock are much less frequent, less infuriating and as I cruise - I know it's costing me less per hour and mile of travel to run the boat today than it did almost 10 years ago. How many folks out there can say that? Of course their are other benefits too but the one that seems to nag folks the most is the return on investment. IMHO- both sides have merit but as I said before- I don't know of a single perosn that has made the change and regretted it. I'll now add that I know of a few people that have replaced gas engines and have regretted not going to deisels.

prowlersfish wrote:

ready123 wrote:I have seen too many negative compromises made when converting gas to diesel .

? negative compromises? Like what ? I would think the pros out weght the cons by far

Pros and Cons are personal assessment... so a compromise for one person can be a NO GO for another.
e.g. It would be unacceptable to loose max: speed capability due to bad boat balance for me. Someone else might find that acceptable as they have no interest in going that fast.
I work from the Scout 'be prepared' outlook and want to have that max: speed capability available should I ever need to run from something. Pirates, weather etc:

ready123 wrote:

prowlersfish wrote:

ready123 wrote:I have seen too many negative compromises made when converting gas to diesel .

? negative compromises? Like what ? I would think the pros out weght the cons by far

Pros and Cons are personal assessment... so a compromise for one person can be a NO GO for another.
e.g. It would be unacceptable to loose max: speed capability due to bad boat balance for me. Someone else might find that acceptable as they have no interest in going that fast.
I work from the Scout 'be prepared' outlook and want to have that max: speed capability available should I ever need to run from something. Pirates, weather etc:

Lose Max speed due to boat bal ??? your still on that kick LOL Your the same guy that said He lost speed dur to 4 blade props but thats ok ?? LOL

I want to run fast that why I have diesels
I don't want compromise thats why I run diesels

come to st mikes this weekend I will show you what diesels will do !!
Hell I even buy your a Beer , We may not agree on some things but we both have great taste in boats

yeah that low max speed thing is a new one to me too. Max speed is related to power versus drag. For sure how a boat handles at speed can can be influenced by weight distribution- but thats true for gas or diesel.

With todays lightweight diesel engines, a can't see a situation where a diesel configuration can't be made as fast as any gas engine for max speed in our boats. The real benefit though is at cruise speeds- where diesel has no gas equalivelant to how a diesel runs at cruise versus consumption.

The Mercs (cummins) were:
"2 - Cummins MerCruiser QSD4.2 engines with gears"

LandVF36 wrote:The Mercs (cummins) were:
"2 - Cummins MerCruiser QSD4.2 engines with gears"

very light diesels a liltle too light for a F36 IMO a setof 5.9 cummins B would make a much better choice better Engine reman would cost less too

We're all pretty smart and frugal peeps - that's how we ended up with ol' Trojans in the first place. Y'all know I toyed with the idea of repowering and found remans here and there for good prices. With new fuel tanks and other things installed when I renovated my F-36, and a few knowledgable friends to help, I had the lowest cost to repower of anyone. But still didn't do it because I don't use the boat enough.

I think this is the rub: If you're a 2 times a month boater like me, use those gas engines up and keep rebuilding them for cheap. However, if you are tempted to do something crazy, like buy a newer boat for big money and rapid depreciation, you are way, way, way better making your Trojan into a new boat.

That $79k estimate was high. I bet you could have a whole new interior in your boat, new electronics, and rebuilt Cummins 6BTAs with new fuel tanks, shafts, gauges, shaft logs, struts, etc etc etc and have a few bucks left over for that money.
No matter how I twisted and turned the numbers, it was gonna cost me $40k to install rebuilt 6BTAs with 200A gears and make it work. The boat is perfect for me and the wife and in very sound condition - so, I continue to kick it around.

I've had friends with much lessor boats lose $40k in depreciation in just a year or two! So, repowering an F-36 with diesels is hardly a wasteful decision compared to what boating costs most people. Hell, my neighbor bought a 43' Meridian for $800k two years ago and couldn't get $400 for it now - THAT is a waste of money!