Post Number: 1
|Posted on Wednesday, June 11, 2008 - 11:06 am: ||
Bear with me.....1st post on this forum:
I am involved with restoring a US Coast Guard lightship in Port Huron, MI. They have three DD 2-71 Gen/Sets and two DD 6-71's for main propulsion. They want to run main engines for display only with no load. (ship is landlocked for display). Question: What size water line supplied with city water would be required to the two 6-71's to supply adequate water to prevent overheating??? Any help is greatly appreciated.
Post Number: 300
|Posted on Wednesday, June 11, 2008 - 12:34 pm: ||
Well they would not need much if there is no load. In trucks 671's have automatic shutters in front of the radiator and if you stop and let the engines idle the shutters close. The old guys used to tell me that when idleing so much air went through the air box into the cylinders that they didn't need any water. I never really belived that. The heads need to be cooled by flowing water. Just measure the intakes and get a pipe that size.
Post Number: 1714
|Posted on Wednesday, June 11, 2008 - 03:18 pm: ||
Interesting project --= and these are just some thoughts -- marine 6-71's cooling systems are quite different than stationary and truck engines that have the advantage of an efficient closed system radiator and mechanical fan to dissipate heat, and the exhaust goes out the dry tail pipe ! marine engines are raw water cooled or the raw water goes through a heat exchanger cooling the water in the engines freshwater system, but both marine cooling methods discharge the cooling water out of the exhaust-- WET Exhaust- messy to deal with ?
A pair of Marine 671s even at 7-800 Rpm will draw in a large volume of water - this water will have to be discharged somewhere- big drain needed.
Run one of the engines and put water intake hose in a 55 gal drum see how long it takes to empty- twice this volume will be needed- use a medium sized fire hydrant to test refill time that should give you close idea of what intake is required !
In long run converting engines to dry exhaust and making a sealed cooling system with a Radiator and fan Like the stationary generators( outside of boat and piped to the engines) would seem to be the way to go ?? Good luck- Keep us posted
Post Number: 3
|Posted on Thursday, June 12, 2008 - 04:47 am: ||
With the present price of fuel I wonder how long they want to run the engines for at a time?
Do you want to simply start one or both up for a short time just to give touring visitors a quick listen to how they sound?
I imagine they are running heat exchangers, but perhaps a lightship built for the Great Lakes did not?
If they are heat exchangers cooled you could run them without damage without water on the raw water side until either they reached full operating temperature or the exhaust stacks got hot enough to require shutdown.
The exhaust manifolds should already be heat exchanger cooled if the engines are. If the exaust piping beyond the manifolds is dry as in a vertical dry stack then it is only the warm up time of the engine at idle that would be your limiting factor.
It could be easy too to plumb the cooling system into another tank such as a fresh water holding tank to gain much more time to run an engine or two before shutdown is required.
If they are equipped with high water temp alarms all the better.
All these ideas are half measures but water is becoming more scarce also so why waste it if you just want to let tours hear an operating propulsion engine. I am surprised how small the engines are. How long is your lightship?
Best of luck to you and your vessel,
Post Number: 2
|Posted on Thursday, June 12, 2008 - 12:18 pm: ||
Thanks for the comments so far. I just got involved with this project only recently and do not have many answers to your questions, but soon will. There is a group of volunteers (some ex-Navy vets) who are "restoring" the engine room. The 2-71 Gen/Sets already run after restoration, but the volunteers are not as familiar with the dual 6-71's going through a combo-drive to a single prop. Ship is 98' long. Additional details can be viewed on their website of: www.boatnerd.com/museums/huron/
I have high hopes for this project. I worked on 6-71's in the Navy back in the 60's, but it has been a loooooong while ago. They just want to "fireup" the 6-71's during certain tours to give visitors a sense of "shipboard" life in the Engineroom.
Post Number: 174
|Posted on Thursday, June 12, 2008 - 08:29 pm: ||
You might locate a mechanical contractor or contact a cooling tower sales rep; BAC or Evapco brand etc, to see if someone would donate a small cooling tower to your project. Maybe the area Pipefitters local union would pipe it up for under their joint aprenticeship program. You might just find some sypathetic ex-navy types in those groups Just a thought...
Post Number: 4
|Posted on Sunday, June 15, 2008 - 09:01 am: ||
I congratulate you on a worthy cause! I went your website and poked around and was touched deeply by the story of the lost crewman and the overheard conversation that led to the reconnection, Wow!
Her's what I saw in the engine room photos,,, The 2-71's were used as heat sources for on station vessel heat for the crew and even the engine room. It will be easy to plumb into that system to take care of any cooling needs for the 6-71's.
The exhausts are dry stacks by the amount of lagging on them, so no issues there to deal with at all.
For a real engineroom feel you will have to heat the air up to 120-130 degrees, LOL. That's what the bouy tender I was on was underway.
I went through Engineman School in 1968 in the USCG and still just love the sound of a 6-71. Those noisy leaking monsters are my favorites!
We used 2 of them in our 40' utility boats, I feel for them having to push 98' of lightship. How are they coupled together? Gears or giant chains? How do you uncouple them, a big sliding dog clutch?
I'll put your vessel on my list of places to visit when I go cross country next.
My antique yacht has a 2-71 installed by the USN in WWII for patrol duty. She is Carib II, sister ship to Henry Howard's Alice, both launched in 1924.