370 DA Is it Diesel worth it?

Jack

Jack

Member
Oct 6, 2006
157
Charlottesville, VA / Deltaville, VA
Boat Info
2002 480 MY
Engines
Cummins QSM11
I have seriously looked at two and surveyed one 370 (both 1998) with gas motors and have found that even after having the exhaust fixed both showed signs of water intrusion damage in their oil. I am now wondering do I find one with new long blocks or is it worth the extra money for the diesels both to avoid water ingestion and for the fuel savings.? I have been told it is like 30 -35 gph gas and less than 15 gph diesel. I only cruise about 100 or less hours a season. Thanks for your advice.
 
To everyone their own ... I have seen 44DAs being purchased with gassers. :smt017

Owning a 340DA and having been on a 380 and 410 with 454MAG Horizons.

I would personally NEVER buy a boat bigger than the 340DA with gassers.

I think they're sluggish all around and to get on plane, you have to revv them higher than I'd like at cruise speeds and the resale is harder on them even if the fuel consumption does not make up the price difference.

I don't think your fuel consumption values are right for diesels ... they're not that much better.

The characteristics and low rpm torque of a disel are just much better fitting when you get into this size of boat.

Just a personal opinion.
 
Most 370DA's with diesels were either 300hp Cummins 6BTA's or 300 hp Caterpillar 3116's. The Cats are a little more efficient than the Cummins and the Cat 3116's will burn 9.7 gal/hr per engine.

The 370DA with Cats is one nice ride. They handle very well maneuver like a sports car. Expect speeds to be near 30kts, in the high 20's anyway.

This particular boat is a poster child for seeing the differences in handling between gas and diesel power. A gas boat with 3 bladed props just does not want to move at idle speeds. You need a little power to get the wheels to bite and the boat to move. With diesels, you best know where you are headed when you put it in gear because its going there right now.
 
FW your comments remind me of the Boatest reports on the speeds and fule consumption of a 380DA with gas vs. diesels. Besides the better handling and characteristics, the diesel version with 3116s had a 30% or threabouts better fuel economy..
 
I came out of a 2001 380 DA and I can say that I feel that boat was too big for gas. I always had to put it in gear and give it throttle to make it move when I docked. My 480 DB is actually cheaper to run (speed vs. fuel consumption and price of fuel) than my 380 gas was to run.
 
The 370 DA is a very hard boat to find with diesels. If you find a good one (or a 380 w/3116's) for that mater, Buy It! I like Gary above had a 380 w/gas engines (2000 model year). Good boat, Lot's of "big-boat"feel but the time spend drinking at the fuel dock was NOT fun. I run a lot bigger boat now and don't burn as much fuel as that 380 did. Good Luck!
 
Do either of you remember your approximate fuel burn per hour at cruise with the gas motors. I'm trying to balance the extra cost of the diesels versus the additional fuel burn. Also, does anyone know what the fuel burn on the cats in a 370 is? Gary, I keep my boat down in deltaville, were you on your boat over the weekend on the bay? If so what was the weather like? I was supposed to bring the 370 that turned out to have a bad oil analysis home this weekend. From what I saw of the weather looks like it was a good thing I did not buy the boat.

thanks
 
I'm not "either of you" but I can help with part of your answer........

You mentioned "balancing the extra cost of diesels vs the extra fuel burn....." . I hope you look at the big picture here. The gas vs. diesel is a lot bigger subject than just the fuel burned.

For example, diesel fuel is available nearly everywhere now as "off-road" fuel. It is dyed red and has no highway taxes added to the price you pay at the pump. So inaddition to burning less fuel, you are burning cheaper fuel.

Then there is the mainenance isses. SOme debate me on this, but I have found my Cat diesels (over a 10 year period) to be easier and cheaper to maintain than a pair of 7.4's I ran for 9 years. No tune ups, no plugs & plug wires, water pump impellors run about 300 hours, no more of that checking and replacing riser crap.......etc.

And, there is a quality of investment difference. You cannot look at boats an an investment, but at some point we either sell the boat or trade up down etc. You will get more of your initial investment back with a diesel boat than you will with a gas boat. Said another way, the upcharge for diesels stays pretty constant so you get almost all of the premium back meaning that there is no or very little cost differential over all. For example, in 1989 I bought a 1 year old 390EC with gas engines.....there was a $50K difference between gas and diesels at the time.....when I sold the boat, 9 years later, diesels were bringing about $135K and we sold our gas boat for $90K....a $5K loss over 9 years. Sure, had I bought a diesel 390 my investment would have been larger, but I also would have spent less on fuel and maintenance...........so was there a real "extra cost for diesels?

On the Caterpillar fuel burn numbers, diesels are different than gas motors. A diesel engine will burn the same amount of fuel no matter if its in a trawler or a Sundancer. So, no matter what boat is in, at 2400 rpm (rated cruise) a 300 hp 3116 burns 9.7gph; a 350hp 3116 burns 11.3 gph and a 420 hp 3126 burns 13.0 gph.

Fuel burn on gas motors is dependant upon load, so you'll have to get actual experience from a 370/380DA owner.

And you thought this was going to be an easy calculation.......!
 
Thanks Frank,

Everything you listed was what I have been trying to use in my decision as I plan to own the boat for more than 3 or 4 years. Would you use the number of hours you plan to run the boat in the calculation? Coming from a 290 this decision is new territory for me as I can buy a gas 370 (1998ish) with "new" gas motors in the 140 range and the diesel looks to run about 175 plus. Life was alot simpler when I was looking at 340's but then I got on a 370 and my mind was made up. Thanks for your continued help. What is the weather like in PC these days?
 
Jack,

I was on my boat but I did not go out on the bay. As my dock went underwater, I just stayed on and kept adjusting the lines. I'm stupid... I know.

I have only gone out intentionally on the bay one time in a gale from the NE.... and it was and will be my last... I took a wave over the back of my 480 (buried the back) and my son was in the cockpit and he almost went over the edge as he was flushed to one side. He was in good spirits about it and and came on the bridge and said "hey dad... you trying to kill me". We were going "fishing".... one of the top 20 stupid things I've done on the boat.

On topic though... Get diesels... My 380 was a really great boat but had the wrong engines. "Incremental" costs hurt far more than "capital" costs when using the boat.... and like Frank said, the simplicity is nice. My 20 foot jet boat with a 6 cylinder two-stroke inboard (240 hp) gas engine is a nightmare to diagnose and maintain compared to my Cummins diesels. And the jet boat burns 15-20 gph for 4000 lbs. Imagine that. It does feel good though.
 
Jack,

Hours is important to the extent that once you determine the cost differential in operation, its easy to expand that to planned useage to get a savings total.

But there are other factors as well. Once you get a diesel powered boat, you will put more hours on it than you ever did on a gas boat. They are so much fun to operate since they handle much better, and since it does not cost an arm and a leg to run over to the next town for lunch you are more apt to take the trip.

One more facet of diesels is that you are no longer talking about a 1000-1200 hour total life span like gas motors. I have a friend who has 3126's in a charter boat in Florida and he's at 12,000 hours with no major repairs....only water pumps, adjusting valves a few injectors, a starter, and a car load of Racors and Cat primary filters. Generally, the buying public expects to buy a boat with total time equal to 100 to 150 hours per year. As long as there is a maintenance/service record and required manitenance has been done, significantly more than that is acceptable for diesels.

Ltst wee the highs in PC were in the low 80's, nightime about 60.......in 2 weeks, we had one day that I saw a cloud.......truly boating in paradise!
 
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As the owner of a 37 gasser I have to agree with the majority of Frank and Gary's thoughts here. They speak from experience. I would love to have gotten diesel when I bought my boat but I specifically choose gas for reasons that apply to my situation and my not apply to yours. To begin with I was focused on initial cost and while the resale argument is very valid money is money and I purchased my boat with a very long plan of ownership (10 to 15 years) the time value of money from additional resale value 15 years down the road doesnt play much into current plans. I also chose gas for two other major reasons. One is maintenance, granted the gassers need more but I just had a higher comfort level in my ability to handle the work myself and the potential cost exposure if somthing goes horribly wrong. While a pair of Cats would require less ongoing maintenance dollars in the face of a major repair the gassers will always come up much cheaper. I remanufactured 7.4L long block can still be had for under 3K. The other reason is the minimal cost savings the added efficency diesels would have provided me BECAUSE I just dont run that many hours each season. I spend huge amounts of time on my boat and always have but generally not running big hours. I think I put about 35 hours on her this season which is about normal for me. At this low usage the added effeciency advantage is just not that big. That having been said at 3200 RPM cruise which provides about a 19 knots my rough calculations indicate about a 36 GPH fuel burn or about 1/2 knot per gallon. As far as close quarter manuvering yes you need some throttle but I have pleanty of confidence handling her as once you get the feel of what is required I have not problem putting the boat anywhere I need to.
 
I have diesel in my vascular system, so here's alot of oppinion and some useful factoids.

Diesel is more plentiful
Diesel engines have a 4-5x longer life span.
Diesel engines are less expensive to "tune up"
Diesels have a higher resale value.
Diesel engines burn 40-60% less fuel than a gasser.
Diesel engines produce 80-90% less Carbon Monoxide than gas.
Diesel powered boats do not require powered ventilation of the bilge per ABYC.
Diesel powerd boats are better.
There are many diesels available to replace gas. Not just Cat and Cummins.
Diesel is a long term investment. If you turn your boat over in less than 10 years, it might not be an option.
Insurance on a diesel boat is less expensive. Due to the less volitle nature of diesel.

Thats my oppinion, I have a vested interest.

Pat McCartin
Inland Marine Diesel
Buford, Ga
 
Decisions Decisions...... I have alot more to think about than I did before asking this question but that is a good thing. I think I will do abit more searching and see what I can find in the market as far as deisel boats are concerned. Frank, where was that picture taken, (shell island?) compared with our weather it makes me jealous. My inlaws are meeting us at duck NC next week and they are already aking about the cold weather. Thanks again for all the input, I'm sure I will have more questions as I continue my search.
 
We had a 1995 370DA for 2 years. Great boat, but it was a gasser. As others have mentioned, it was sluggish at low speeds. But you can get used to it.

As for fuel burn, we averaged about 20 GPH cruising at 3400 RPM, so I'm a little confused about the higher 35 GPH numbers being mentioned. Is there a difference in the engines from '95 to '98?

Anyway, bottom line - get diesel if you can. The ONLY thing I would be concerned about would be bilge space with diesels. We've now got a 410 with 3116 CATs and I can tell you the 370 gasser had more space in the bilge to move around and do work. I had to change the holding tank filter once - ever see that swammi who contorted himself to fit into a 2' square box? That was me changing that filter on the 410.

Good luck with the search.

David
 
DS410 said:
As for fuel burn, we averaged about 20 GPH cruising at 3400 RPM, so I'm a little confused about the higher 35 GPH numbers being mentioned. Is there a difference in the engines from '95 to '98?


David
Click to expand...

Are you sure about the 20GPH number....that sounds VERY low....my 98 330 with 7.4MPI would burn close to 30GPH at 3500RPM my current 380 with 8.1's burns 32-33 GPH at 3500RPM.....
 
Yes, I'm sure of the numbers. We checked them several time throught the boating season with a final tally at the end of the season. The 370 had carborated 454's and we ran her usually around 3400 - 3500 cruise, which put her at about 19 knts on avg.

When we were looking at the 410, I remember thinking that the fuel burn wouldn't be that much different, but then again, the 410 was a much bigger, heavier boat. (22,000 lbs. vs 17,000 lbs.). So far, the 410 seems to burn about 22 - 24 GPH, which, from previous discussion, looks like it's right around where it should be. (BTW, this is only our first season with her, so . . .)

David
 
DS410 said:
Yes, I'm sure of the numbers. We checked them several time throught the boating season with a final tally at the end of the season. The 370 had carborated 454's and we ran her usually around 3400 - 3500 cruise, which put her at about 19 knts on avg.

When we were looking at the 410, I remember thinking that the fuel burn wouldn't be that much different, but then again, the 410 was a much bigger, heavier boat. (22,000 lbs. vs 17,000 lbs.). So far, the 410 seems to burn about 22 - 24 GPH, which, from previous discussion, looks like it's right around where it should be. (BTW, this is only our first season with her, so . . .)

David
Click to expand...

I think all of these numbers are way low if they are for continous cruise and not a cruise/idle/putts around fuel consumption mix number... Big Blocks in these boats burn usually at least 15 GPH PER ENGINE (!) at 3200 to 3400 rpm ...
 
Alex D said:
I think all of these numbers are way low if they are for continous cruise and not a cruise/idle/putts around fuel consumption mix number... Big Blocks in these boats burn usually at least 15 GPH PER ENGINE (!) at 3200 to 3400 rpm ...
Click to expand...

20GPH is about right for my 340. Of course, that's per engine.

:grin:
 
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