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09-07-2014, 03:22 PM
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#21
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Member
City: Tortola
Join Date: Apr 2014
Posts: 14
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Thank you for all the input. I saw the post on the HOF by coincidence.
I have been reading about these Detroits and then started reading about the Caterpillars 3208TA at 375hp. The Cats seem to have better "reviews" and from what I have been able to figure online run well and cheaply at low rpm.
Does any one have any real fuel burn numbers for running the 3208TA/375s at low rpms on a 45ft, 35,000lb semi displacement taiwan trawler style or similar?
I'm reading that at 1,200rpm and approx 7.5 knots burn can be as low as 8gph (4gph per engine)...?
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09-07-2014, 04:03 PM
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#22
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Guru
City: North Carolina for now
Join Date: Aug 2011
Posts: 6,348
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Really suggest you subscribe to boatdiesel.com for comprehensive info and opinion. The Cat 3208 at 375 or less is a good engine too. The Detroit is easier to rebuild without removing. Fuel burn (such as what you say you are reading) in a given boat at a given speed is not going to be very different if at all. There is more urban legend about the DDs than any other engine.
__________________
George
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
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09-07-2014, 06:32 PM
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#23
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Veteran Member
City: Akureyri
Vessel Name: Ozimo IV
Vessel Model: 18m Gulet
Join Date: Feb 2014
Posts: 83
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On the present ship we have four 671NA - 250hp each - two per 6" shaft + three 471NA gensets. The one thing you need to remember is that DD's use oil. We keep a couple of barrels on hand for the lube tanks.
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Capt Freddie
M/V Ozimo IV
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09-07-2014, 06:36 PM
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#24
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Veteran Member
City: Akureyri
Vessel Name: Ozimo IV
Vessel Model: 18m Gulet
Join Date: Feb 2014
Posts: 83
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Quote:
Originally Posted by amelis
Thank you for all the input. I saw the post on the HOF by coincidence.
I have been reading about these Detroits and then started reading about the Caterpillars 3208TA at 375hp. The Cats seem to have better "reviews" and from what I have been able to figure online run well and cheaply at low rpm.
I'm reading that at 1,200rpm and approx 7.5 knots burn can be as low as 8gph (4gph per engine)...?
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Skip the turboed engines - and go with the naturals. My four NA's have more than 35,000 hrs on them without rebuild. I don't know of a single turbo engine that will last as long and that's one of the reasons they built them.
I'd have to do some figuring for gph, but our engines run continuously at 900rpm 24/7/365 - and we measure consumption in cubic meters.
__________________
Capt Freddie
M/V Ozimo IV
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09-07-2014, 07:40 PM
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#25
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Guru
City: Windsor
Vessel Name: Keeper IV
Vessel Model: 44 Viking ACMY
Join Date: Nov 2013
Posts: 1,350
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Quote:
Originally Posted by Ghostrider42
Skip the turboed engines - and go with the naturals. My four NA's have more than 35,000 hrs on them without rebuild. I don't know of a single turbo engine that will last as long and that's one of the reasons they built them.
I'd have to do some figuring for gph, but our engines run continuously at 900rpm 24/7/365 - and we measure consumption in cubic meters.
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OK inquiring minds need to know. What is this vessel.? USCG?
Sent from my Nexus 7 using Trawler
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09-07-2014, 08:51 PM
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#26
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Guru
City: Venice Louisiana
Join Date: Dec 2013
Posts: 1,097
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The 3208 is a 636 CI engine. Again swept area is fairly large as are parasitic losses (the power required just to spin the engine). It will take as much to turn these engines as your boat can use at hull speed. 1 mpg seams to about normal for go fast boats in the 40 to 50 foot size when ran below hull speed. The 3208s being 4strokes are easier to deal with at low speeds than the hopped up DDs. But, at 375 hp on an engine designed for 210 hp wont last to long, even less at 435. Kinda like the 6-71 at 485 hp. A grenade with a loose pin.
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09-08-2014, 06:02 AM
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#27
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Guru
City: North Carolina for now
Join Date: Aug 2011
Posts: 6,348
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Quote:
The 3208s being 4strokes are easier to deal with at low speeds than the hopped up DDs. But, at 375 hp on an engine designed for 210 hp wont last to long, even less at 435.
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Could you define what you mean by "long"?
Thanks
__________________
George
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
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09-08-2014, 08:07 AM
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#28
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Guru
City: Venice Louisiana
Join Date: Dec 2013
Posts: 1,097
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At 435 hp the 3208 has about the same life expectancy as a 550 hp DD 8v71, less than 3000 hours befor needing majored. The difference is the DD can be easily rebuilt (liners pistons rods/bearings, mains, heads) and its back in business. The 3208 was not designed to be rebuilt (parent bore block) so is much more labor intensive to R & R. And, for numerous reasons the rebuild is sometimes not to successfull. As far as the life of these engines are concerned, I'm talking about engines that are used mostly at there rated power. I know, some will say "well, my loose pin grenade has 20,000 hours on it and still runs great" but it was not ran much at rated power.
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09-08-2014, 08:28 AM
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#29
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Guru
City: North Carolina for now
Join Date: Aug 2011
Posts: 6,348
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The 435 is known as problematic and I'd say 3000 is about right, if not on the high side. It was your comment about the 375, which I have seen running great at 5000 hours in 20+ year old boats we've chartered, plus having met people with over even that on them, that led to my question.
__________________
George
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
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09-08-2014, 09:46 AM
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#30
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Guru
City: gulf coast
Join Date: Jun 2014
Posts: 3,440
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George:
I can think of hundreds of diesel owners, all brands ,who would benefit from your report . It destroys a lot of myths.
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09-08-2014, 10:12 AM
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#31
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Veteran Member
City: Akureyri
Vessel Name: Ozimo IV
Vessel Model: 18m Gulet
Join Date: Feb 2014
Posts: 83
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Quote:
Originally Posted by mbevins
OK inquiring minds need to know. What is this vessel.? USCG?
Sent from my Nexus 7 using Trawler
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Duh - can't read the signature I guess. 28m ocean tug. I have an original 671 that was taken from a river tug and made into a genset with more than 39000 hrs on it - no rebuild.
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Capt Freddie
M/V Ozimo IV
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09-08-2014, 10:16 AM
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#32
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Veteran Member
City: Akureyri
Vessel Name: Ozimo IV
Vessel Model: 18m Gulet
Join Date: Feb 2014
Posts: 83
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Quote:
Originally Posted by kulas44
The 3208 is a 636 CI engine. Again swept area is fairly large as are parasitic losses (the power required just to spin the engine). It will take as much to turn these engines as your boat can use at hull speed. 1 mpg seams to about normal for go fast boats in the 40 to 50 foot size when ran below hull speed. The 3208s being 4strokes are easier to deal with at low speeds than the hopped up DDs. But, at 375 hp on an engine designed for 210 hp wont last to long, even less at 435. Kinda like the 6-71 at 485 hp. A grenade with a loose pin.
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3208TA's aka - throwaway engines. First put into buses and otr trucks. Rarely last more than 350k miles. In the meantime 6BT mechanical two valve Cummins went 500k before rebuilds and last 1M miles or more. Newer electronic four valve Cummins struggle to last 500k miles. Most never see 1M miles. Worse yet in slow speed marine applications. TA's were built for speed not longevity.
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Capt Freddie
M/V Ozimo IV
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09-08-2014, 10:34 AM
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#33
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Guru
City: UMR MM283
Vessel Name: Northern Lights II
Vessel Model: Bayliner 3870
Join Date: Jan 2013
Posts: 1,357
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Quote:
Originally Posted by Ghostrider42
3208TA's aka - throwaway engines. First put into buses and otr trucks. Rarely last more than 350k miles. In the meantime 6BT mechanical two valve Cummins went 500k before rebuilds and last 1M miles or more. Newer electronic four valve Cummins struggle to last 500k miles. Most never see 1M miles. Worse yet in slow speed marine applications. TA's were built for speed not longevity.
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The Cat dealer in Kansas City in the early 1980s had a fleet of Ford F-600/ F-700 field service trucks with na 3208 power. The parts and service rep who had been a field mechanic told me that about 90,000 miles the bearings would start to flake so they would roll in a new set between 70,000 and 80,000 miles and they were good to go another 90,000. The dealer had their own oil lab and that's how they identified the problem
__________________
Ron on Northern Lights II
I don't like making plans for the day because the word "premeditated" gets thrown around in the courtroom.
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09-08-2014, 02:36 PM
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#34
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Guru
City: LI or Fla
Join Date: Jul 2013
Posts: 1,148
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Going from a sailboat to a 53 Hatt with DD is quite the paradigm shift in boating, if true longer range cruising is your interest then I suggest a little smaller and more trawlerish (is that a word?)type.
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09-08-2014, 02:44 PM
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#35
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Senior Member
Join Date: Oct 2007
Posts: 323
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yrs ago i was capt on a 58 hat with 871s ti and it used 30 gal hr doing 16knts 15 gals per hr on each engine. i ran it at 1900 rpm all day long back and forth to florida every year for about 4 yrs and it never changed it was always 30 gals hr
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09-08-2014, 04:55 PM
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#36
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Guru
City: North Carolina for now
Join Date: Aug 2011
Posts: 6,348
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Quote:
Originally Posted by capt jerry
yrs ago i was capt on a 58 hat with 871s ti and it used 30 gal hr doing 16knts 15 gals per hr on each engine. i ran it at 1900 rpm all day long back and forth to florida every year for about 4 yrs and it never changed it was always 30 gals hr
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Sounds about right at that speed.
Quote:
George:
I can think of hundreds of diesel owners, all brands ,who would benefit from your report . It destroys a lot of myths.
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Huh? i did? or some other George maybe?
Quote:
3208TA's aka - throwaway engines. First put into buses and otr trucks. Rarely last more than 350k miles.
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"throway engines" immediately IDs an urban legend user. Besides: 1) 350k miles in that use equates to 9000 hours or so. 2) we ain't driving busses here
__________________
George
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
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09-08-2014, 05:32 PM
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#37
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Member
City: Tortola
Join Date: Apr 2014
Posts: 14
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Quote:
Originally Posted by Marlinmike
Going from a sailboat to a 53 Hatt with DD is quite the paradigm shift in boating, if true longer range cruising is your interest then I suggest a little smaller and more trawlerish (is that a word?)type.
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Yes, that was the plan. Only we are in Europe and there are not many displacement boats around. Hence the interest in semis with the bigger engines.
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09-08-2014, 06:10 PM
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#38
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Senior Member
City: Foley, Alabama
Vessel Name: GITANA
Vessel Model: Sea Ranger 47 Pilothouse
Join Date: Mar 2012
Posts: 315
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Brother, I'd go for the Lehman powered boat. You'll save big bucks over time. Years ago I operated the last functioning PT boat in Key West (DD 8v71TI powered). Most of our tours were done at idle power settings, and those beasts really sucked fuel. I'd strongly suggest you continue looking. When diesel was .15/gallon (and yes, I'm old enough to remember those days), the DD's made good sense. Now? Damn shame too. The old 71-series Jimmies are my favorite engine of all time...save for the blood price of fuel!
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09-08-2014, 07:57 PM
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#39
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Senior Member
Join Date: Oct 2007
Posts: 323
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the old saying yrs ago was you can buy parts for DD in any corner drug store,all over the world LOL
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09-09-2014, 06:33 AM
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#40
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Guru
City: Annapolis
Vessel Name: Ranger
Vessel Model: 58' Sedan Bridge
Join Date: Aug 2013
Posts: 7,088
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Quote:
Originally Posted by Captain K
Years ago I operated the last functioning PT boat in Key West (DD 8v71TI powered). Most of our tours were done at idle power settings, and those beasts really sucked fuel.
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That might benefit from some additional context. If you mean 4 GPH at idle speed is really sucking fuel, that's slightly different from 30 GPH or whatever.
We burn something like ~0 GPH per engine at idle at ~+/- 5 kts, but more like 13.4 GPH (nominal) per engine at 2200 RPMs and 18-19 kts.
One of those is sucking fuel, the other, not so much...
OK, so a different comparison, we burn more like 2 GPH at 1000 RPMs at about 7 kts. Compared to a smaller 80- or 100-hp diesel in an efficient hull form, that's probably a lot, maybe even sucking fuel. In the grand scheme of things in my wallet, bearable for now.
-Chris
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Chesapeake Bay, USA
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