What ever happened to detroits in work boats?

Badlatitude

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We've got a total of 6 detroits on the 2 boats i work on at home, 3 12-71ti's, 2 6v-71's, and a 4-71 for a generator. They sure are some workhorses, all of them on their umptienth rebuilt and most of them still going strong. The 4-71 has god knows how many hours on it, it just keeps going strong. I love the old detroits, but they are heavy, loud, and thirsty, im sure thats why people get away from them, just better options out there.


rgr that. The reason this question occured to me was just that. I mean how much better are they? Whats the difference in fuel burn for the given power? I remember our "tank engine" being a loud old bastard that loved its oil. The yanmar that went in was a little quieter and a little better on fuel and was always clean enough to eat off of. But at the time I think we were paying $1.72 for fuel oil so I didnt really care. We carried 300+/- gallons of fuel and fished fairly local anyway.

Seems like the question got off topic a bit but we wouldnt even be able to go through hells gate on a moving tide with an 8knot boat for example. I think a 15-20 knot cruise is a comfortable speed.

Seeing how many lower cost gas and 100-200hp diesels are for sale theese days that just endlessly stay up for sale it got me thinking was all.
 

WoundUpMarine

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Badlatitude

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We had a Mack 237 like that. Burned a gallon of oil a day, stunk and smoked like a bastard but it never stopped running.
 

F/V First Team

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Maybe salesmen got better at slinging iron?

Growing up in the boat shop I've been on my fair share of vessels, the majority of which were 2 cycle Perkins and Cats, the occasional triple nickel tossed in for flavor and at least one Detroit (4-71 that is still going strong as far as I know). Weren't exactly speed demons back in the 80's, but then again they weren't producing nearly as much power. The exhaust stacks alone could tell you that, no more plumes of soot rocketing out when the throttle was slammed forward on sea trials and gone is that sweet sweet smell of exhaust that only a 2 cycle can produce.

The entire industry has changed since those days, lighter engines mean more accommodations/fuel/payload for the vessels without altering a whole lot as far as final weight. Are these new engines better on fuel than their ancestors? Sure. Well, maybe. Possibly. Some might be the same, others might outshine their predecessors, and I am sure that there is more than one out there that has slightly worse fuel consumption in parts of the power range. The engines are producing more power as far as displacement and weight go, I doubt any of us can argue that. Now I'm not talking about rounding up quarters to jam into the rack of the governor to get more out of that Detroit, but I'm talking about out of the box every day engines.

I don't know how many boats slid out of the doors that peaked at 15-18 knots, but those were quite fast in their day. Built the old school method, like tanks inside brick shit houses. Nearly everyone had a 2:1 gear and a square wheel, not exactly what one would want for a go-fast boat - but then again that wasn't the mentality. These days everyone wants a cruising speed of 20-25 mph, like there is some dial on the bottom of the hull that we can just twist and turn to tune that speed in (there totally is, it's right next to the gravity switch so we can work upside down - shhhhh let's keep those a secret just between us though ok?) and in all reality the only way to do that is to put in a higher horsepower engine when compared to the good ol' days. Couple this fact in with their lust for 10 lbs of stuff in a 5 lb bag and well now you're looking at an even larger engine. All to guarantee that magical speed. Are most people going to actually cruise at this speed? No, probably not. Either its too fast, too rough, too costly, too noisy, or just too TOO for them. Every boat is different and every skipper is different (sometimes in more ways than one...) and when you get used to a certain way of doing things, well anything else is just plain old strange. I stepped off my boat and onto another for a project going from 8 knots at idle to 6 knots being the maximum speed for 90% of the day. With double the horsepower! Granted, it was a 48' vs my 36', it had twin cats in it where I have but the single engine, and a lot of other stuff wedged into it - but even so, I was not prepared for the speed change. Later on with another project aboard that vessel I did get it up to 14 knots, although that was with a solid 2+ knot current coming out of Woods Hole, it was maxed out at 12 and couldn't hold it there for very long.

Detroits have their place, nearly everyone is fond of their old two cycle, and some are not. It is true though, I haven't seen Detroit iron being slung at many shows and hardly hear let alone see any of the newer ones at the races or new builds as the pop up every now and then. Maybe this is because MTU isn't marinizing many engines anymore, last place I saw one was up at the Moncton show and for the power it was producing, 800 or so, it was way too massive and way too heavy for my consideration. The Volvo had my attention for that one. Marine engines typically are less than 1% of any engine manufacturer's production and sales, so needless to say we don't get a whole lot of attention. If engines for agriculture and gen sets are up, marine engines go down onto the back burner. It's no secret that the marine industry as a whole has been having a rough time since 9/11, this past administration has really kicked it in the kidneys in my opinion, so everyone is basically riding the wave to see what happens. Shelves are half stocked, if that. Companies want to be paid in full before an order is fulfilled so they don't have to run the risk of having an item sitting around. Warehouses cost money, and if the products are just sitting then that initial cost starts creeping up to the point where you make nothing on them or you're in the red when you finally do offload them.

Everything is tied together which is a given for any industry - the pie is only so big. And the thread which ties all industries together: fuel. Lower fuel prices would surge all industries forward and you'd probably see heavier engines start making a comeback. Would it be the venerable Detroits of yesteryear? It's hard to say. Maybe that dog has spent too much time on the porch and people have forgotten how she used to hunt in the woods. Or maybe, just maybe, that new litter of hers will be the best thing going - they just need to wait out the hard times and grow up a little.

Fun fact: the original First Team, 28 Northern Bay had a Detroit in it. Found this nice 8.2 that was a low hour takeout and that was nestled in on her beds. We figured that it might do 15-18 full tilt boogie and since we were just going to be fiddling around in the bay here that would be fantastic. Then the question arose "would you like to go racing?" and well, that V-8 was yanked out the next day and a very cute I-6 dropped in her place. It didn't fit very well and was a pain in the ass to assemble there below the deck - a cylinder and a half was now forward of the bulkhead, but on sea trials she ran 32. Don't feel bad for a minute that I never got to fire that Detroit up. :-D
 

eztbone

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My first experience was on a old charter boat steel 65' with twin 671 naturals from 1946. Cruising speed 8kts. We changed one out in the early 90's and the other in 2002. We ran that boat to Florida and back every fall on those motors. Very reliable. But a slow ride to Florida. We would run 24/7 from mass to ft lauderdale. First fuel stop coinjock nc. Second fuel stop st Augustine. My 38 holland has a 6v92 with about 200 hrs on a rebuild. I burn a reliable 20gph at 1900 rpms and 16 kts.
 

WC1966

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I have a 1966 Webbers Cove 34 with DD 6v53N, circa 1972. When I bought it the hour meter said 2450, and did not work, prior owners did charters and used the boat hard. The only part of the boat I have not had to fix/rebuild/replace is the motor. If it ain't broke:rolleyes:
I use it to fish locally in Long Island sound with a couple trips to BI.
I thought about a new motor, the price scares the hell out of me, and if/when this one blows up I will probably put in the same thing. I have no issue with running at 10-14 knots, part of growing old is enjoying the journey.
And the Scottish heritage tends to be frugal.
wish this forum was around 10 years ago, could have saved a lot of trial and error, :confused:
 

tunaorlater

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No engine raises tuna like a Detroit. And no other engine smells more like a garbage truck then a Detoit! :)
 

CEShawn

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I even got to play with a Grey Marine Diesel which I believe was the block that became the 671... Fuzzy on the history but I think the original block was used in WWII correct? I think a few people made them when they had to get done for the cause.

I ran a pair on an Ocean 48 and then had a trio on a tugboat as generators. I just remember them drinking lots of oil but not needing many parts, ha! Ive actually operated more NA then turbos...

Its funny, but maybe there are more out than then you think of, but anytime I hear of rebuild in the early 2000's it was always a 92 series... I remember when my marina was stacked with 92 rebuilds... The other thing is I never ran into someone who had a high hour 92 series without problems... I think that is just a odd figure as I have to imagine they were better than what I heard of... but then again...
 

badabing

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having just replaced my detroit 6-71 last year i can give a few reasons why they are great and why they aren't. first off mine was ina 44 by 18 foot novi boat towing a dredge and it was enough power even hooked up to a 3to1 gear with a 34 inch wheel. it seemed like it would leak alot less oil at 1400 rpms or less and we were running it right up to 1800 rpms towing and the sound....well im sure many of you can relate. i was burning up to a quart of oil an hour before i would rebuild it. i rebuilt twice over the last 8 years. i only got 1200 hours out of the first rebuild because the rings cracked and when we took the head off the old time gloucester mechanic showed us the mistakes the first "mechanic" had made. the most critical part in the 6-71 rebuild was setting the sleeves at the correct tolerance so they meet the head correctly and it is a absolute bear and very time consuming to take the sleeves in and out to shim them to perfection and this is where the first guy cut corners. it never ever let me down and always got me home. anyhow we had a few good years and i broke down and replaced it with a cummins qsm11 405hp. i went from one end of the spectrum to the other, now having vessel view and never adding oil....nevermind every 3 or 4 towes like i did for years.
 

Tuna Pursuit

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Go figure this... in the summer I am on vacation...

If I need to steam 100 miles to the canyons. If I go at 14kts I burn 10GPH, which is $40/hr so figure $560 for the back and forth cost. That will take 7 hours each day or there abouts.

If I go at about 7.5/8 knots I burn just about 1GPH. It takes me 13 hours but I've burned $50 in fuel... $50 on the way back... $100 vs $560...

When we go down there and do not catch yellowfin its much easier to take a hit like that...

Bingo. Most commercial guys do 7-8 knots for that reason, it's cheap. I know a guy with a newer 36 Calvin and he does 10K all the time.
 

Tuna Pursuit

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I have a 1966 Webbers Cove 34 with DD 6v53N, circa 1972. When I bought it the hour meter said 2450, and did not work, prior owners did charters and used the boat hard. The only part of the boat I have not had to fix/rebuild/replace is the motor. If it ain't broke:rolleyes:
I use it to fish locally in Long Island sound with a couple trips to BI.
I thought about a new motor, the price scares the hell out of me, and if/when this one blows up I will probably put in the same thing. I have no issue with running at 10-14 knots, part of growing old is enjoying the journey.
And the Scottish heritage tends to be frugal.
wish this forum was around 10 years ago, could have saved a lot of trial and error, :confused:


That's a great story. Ya those old "N's" were/are bullet proof.
 

Badlatitude

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I only asked because I can remember so many and see so few. I dont even know how one would go about marineizing one of the govt surplus engines like my old boat had before her yanmar. Bolth of which were raw water cooled btw or marinizing an inline mechanical mack I was so fond of. I dont think anyone does it anymore do they?
 

Prdlobster

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12v92

I even got to play with a Grey Marine Diesel which I believe was the block that became the 671... Fuzzy on the history but I think the original block was used in WWII correct? I think a few people made them when they had to get done for the cause.

I ran a pair on an Ocean 48 and then had a trio on a tugboat as generators. I just remember them drinking lots of oil but not needing many parts, ha! Ive actually operated more NA then turbos...

Its funny, but maybe there are more out than then you think of, but anytime I hear of rebuild in the early 2000's it was always a 92 series... I remember when my marina was stacked with 92 rebuilds... The other thing is I never ran into someone who had a high hour 92 series without problems... I think that is just a odd figure as I have to imagine they were better than what I heard of... but then again...

CEShawn...I have a 12v92 with almost 90k hours on one of my lobster boats. It was rebuilt once in 1999. You're right...all it does drink oil!
 

CEShawn

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I might be heading out to an old ship I was on... It has 4 EMD's, basically big detriots in a sense. I have one that somehow drinks about 20 gallons to just start up. They need about 40 gallons of oil a day to run the 16cyls each... but require few parts so its made up...
 

fvashmarie1

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Dont Know how any one in a charter boat could catch fish with a detriot in there boat those things are vary loud
 

Blitzen

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Blitzen, as you know, I think you have a real sweet ride that is really dialed in and agree with your bit, balanced on all levels...

By the way, 8 knots even though I do it, is DEAD ASS BORING. I did enjoy cod fishing earlier this month for $40/day.... gave me lots of time to relax after being on a ship for 3 months...
Shawn,
That is the beauty of these boats, they have a wide range of efficient operation that still gives a great ride. I have done the same thing when I have the time run slow to save fuel but just think that if that was the only speed you could go and you can't get out of your own way. It is like have a car that only goes one speed.
 

WoundUpMarine

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WC1966

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Shawn,
That is the beauty of these boats, they have a wide range of efficient operation that still gives a great ride. I have done the same thing when I have the time run slow to save fuel but just think that if that was the only speed you could go and you can't get out of your own way. It is like have a car that only goes one speed.
After spending years traveling a 6-7 knots in a sailboat, ya get use to not being in a hurry. 12 knots and up is white knuckle time! And being able to go in a straight line is priceless:D
Merry Christmas
 
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