Detroit 8v71TI

[Ghostrider42]

OK inquiring minds need to know. What is this vessel.? USCG?

Sent from my Nexus 7 using Trawler

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.

 

[Ghostrider42]

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.

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.

 

[River Cruiser]

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.

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

 

[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.

 

[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

 

[caltexflanc]

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

Sounds about right at that speed.

George:
I can think of hundreds of diesel owners, all brands ,who would benefit from your report . It destroys a lot of myths.

Huh? i did? or some other George maybe?

3208TA's aka - throwaway engines. First put into buses and otr trucks. Rarely last more than 350k miles.

"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

 

[amelis]

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.

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.

 

[Captain K]

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!

 

[capt jerry]

the old saying yrs ago was you can buy parts for DD in any corner drug store,all over the world LOL

 

[ranger58sb]

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.

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

 

[Ghostrider42]

"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

350k miles = 12,500 hrs

Before I was driving boats, I was driving school buses and CAT's in the 1950's. I commercially fished the GL, then I started rebuilding diesel engines - so I saw what happens to them when not taken care of properly. Twenty years in the RCAF as - you guessed it - airframe mechanic, then I went to marine diesel mechanic school in the 1970's. Went to Amsterdam - studied hard and got my 100T license and then 1000T a few years after. Still tinkered with DD's and CATS making them work better, not harder.

My brother and Dad and Grand Dad all built boats - mainly from wood and steel. To say that all the good wood is gone - that's just wrong. There's plenty out there, you just need to know where and how much money you want to spend. They never built a single line - it was all custom work. You won't see or find a single one in NA. They were all delivered by me to EU, SA and the ME.

The present 28m ocean tug I own outright. I custom designed it to work better, use less fuel and provide a steady income for my family and my 13 member crew.

So, when I'm done with this tow - I'm back to building beautiful works of art - never will they see anything beyond Greenland or the Irish Sea