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Obie 02-19-2017 09:37 PM

New to me 50, Steel full displacement, engine questions
 
I hope I get this correct. First I am very dislexic so please bear with me a bit.

I have had many boats, and have loved a few thousand open ocean miles single handing. Mostly on sailboats but have had a 48 foot uniflight, and a 42 foot Giles. I have just picked up a 50 foot steel boat, waterline is reported at 45.8 feet, beam is 15' 8". She was built in 1964 as a pilot boat an used in Alaska. She has an original single gray marine 6-71 natural. The wheel is around 36" with a 3" shaft. She holds over 3,000 gallons of fuel
My question here is I am thinking of re powering her. I was thinking a 5.9 cummins would be to small at 210 hp. Maybe a 8.3 cummins. Or I might have an option of obtaining a big cam 4 cummins just rebuilt for around 10k, no transmission. It is just a truck engine. I would keel cool, and dry stack?
I think the 5.9 cummins would stall when you engage? Also I need a hydraulic clutch pump to run bow thruster, and there is a large hydraulic windless for and aft, and a hydraulic crane on the deck.

This is a lot, any help would be great. Realy not sure we're I am going.
Thank you
Obie

Lepke 02-19-2017 09:49 PM

You'd have a tough time finding a more reliable engine than the 671 you have now. What is the issue? The engine is easy to overhaul, parts are everywhere, no electricity need beyond the starter. Many used PTOs are available for the engine front. I recently rebuilt 2 671s for under $5000 including having the heads professionally rebuilt.

RT Firefly 02-19-2017 09:49 PM

Greetings,
Welcome aboard. If she's running now, why repower? Save the 10K+ for filling that 3000 gal tank.

Nomad Willy 02-19-2017 09:50 PM

What's her displacement?
Welcome to the forum.

BandB 02-19-2017 09:53 PM

That's my question as well, WHY repower? What's your reason. That may also play a role in determining the best choice for a repower if you do so.

Xsbank 02-19-2017 10:04 PM

I have a 6CTA 8.3, M1 (250 hp) it is keel cooled, dry stacked and throws a 36" wheel on a 2 1/2" shaft. She also has a pto hydraulic pump and a belt-driven fire pump. She never stalls when I put her in gear and she's happy (but very noisy) at wot, 2100 rpm.

The 6CTA would be just fine, but like the other posters, why do you need to re-engine? Any chance of a picture of your boat?

healhustler 02-19-2017 10:05 PM

Have to agree on keeping the 671. There's a few boats out there that I may change out for a 4 cycle option, but you've got one that a singing Detroit just seems appropriate.

swampu 02-19-2017 10:16 PM

My vote is to keep the jimmy's, I love mine

O C Diver 02-19-2017 10:47 PM

Had a Grey Marine in one of my charter boats. The engine was built in 1944. For as big as it is, it's only 168 HP, but lots of torque. My recollection is that the head configuration limited the injector size, so not really possible to increase the HP. Not sure when they changed the head design to increase the HP.

Ted

O C Diver 02-19-2017 10:52 PM

To turn a 36" wheel, she must have a really big gear ratio, maybe 4:1 or better.

Ted

T4Liberty 02-19-2017 10:59 PM

Unless there is something major damaged beyond repair (block), I can't endorse trading a DD671N for any of the very fine motors you mention. My vote is every engine should be a Detroit.

O C Diver 02-19-2017 11:06 PM

Quote:

Originally Posted by T4Liberty (Post 525341)
Unless there is something major damaged beyond repair (block), I can't endorse trading a DD671N for any of the very fine motors you mention. My vote is every engine should be a Detroit.

They also make fine mooring blocks because of their weight. :rolleyes:

Ted

Obie 02-20-2017 12:18 AM

That's a lot of votes for keeping her. I want to say thanks first of all for your responses.
So I just picked her up. The previous owner passed suddenly, he owned a diesel truck shop. He was in the process of undoing the motor to pull it. Suposubly she ran great 2 years ago befor she went on the hard. But she had an oil Annalise's that showed some metal in the sample. I had another JT 6-71, it had to be rebuilt at tacoma diesel, bill was $25k. I was thinking I did not want to put any money into that old of technology. I can see in the log books were she has been rebuilt twice already. I am a fan of the 5.9 cummins, I like the idea of a non merinized motor I can get parts for anywhere. But with that said I am not against looking into keeping the 6-71. It seams parts are getting a bit hard to find, who know what kinda shape the heat exchangers are in, transmission and so on. She is a single diesel so it's kinda important LOL.
Pictures to come. I am in Mexico right now, so it will be a bit.
Obie

Again thanks

Mako 02-20-2017 02:25 AM

Obie it sounds like a nice workboat.

I had problems with my previous pair of Grays also before I overhauled them, but it's incredible how durable they are (mine were 50+ years old). As long as you can rebuild in-frame and don't need to haul the block then there is little advantage to repowering. You're an experienced boater and must have an idea of the amount of effort required just in creating new engine mounts alone.

You stated that your Gray was natural, which is a totally different animal than the hyper-charged J&Ts. Parts are NOT getting hard to find (just open up Boats&Harbors), they are quite readily available anywhere in the western hemisphere (not here in Qatar), and a rebuild shouldn't be too expensive. You may wish to consider switching out the 2 valve head for a 4 valve.

Save the money of a repower and just add some modern sound absorbing material. Except for the noise, they are such impressive engines that I seriously considered installing one in a new construction trawler, although the fuel efficiency isn't that great either.

sunchaser 02-20-2017 06:57 AM

A newer engine design is well worth considering. As previously mentioned, exhaust system, mounts, driveline etc all carry time and costs to replace if your new engine is not a 6-71. This money and labor stuff can all be calculated and suitable contingencies applied.

But, it is an older steel vessel. Is the basic structure, tanks, interior re-fit etc worth the money and effort? If so, a repower with a newer 6-71 vs the Cummins is worth considering too. DD made many positive changes to the 6-71 over its many years, even the lower HP versions. Nothing magic about the Graymarine other than nostalgia for those of us that have no skin in the game.

Many interesting options for what could well be a very stout vessel. Sounds like a fun project. Enjoy.

FF 02-20-2017 07:31 AM

". But she had an oil Annalise's that showed some metal in the sample. I had another JT 6-71, it had to be rebuilt at tacoma diesel, bill was $25k."

Engines are built of metal, there is ALWAYS some metal in the oil.Read the paperwork to see what it was.

Most JT engines I have seen were for sport fish , very high power ,high RPM and turbo, perhaps for 1000 hours then rebuild.

No comparison to a 20-30,000 hour NA engine run at 1500 - 1800 RPM.

Ours is a 6-71 from 1954 War Reserve with TD 3-1 tranny .

IF you can find the fuel consumption log at cruise you can easily decide if a different engine will be strong enough.

I would go to the JD farm folks and get a completer factory rebuilt and put your old tranny on it.
JD has farm sales with no core charge at times.

If you can do a real low buck conversion the International DT 360 and DT 466 are fantastic sturdy engines with SAE tranny mounting .Mechanical or electric injection , probably $3,000 or less for either.

Obie 02-20-2017 10:37 AM

3 Attachment(s)
Pics

Obie 02-20-2017 10:49 AM

Just a few pics, I think she is around 50 ton.

RT Firefly 02-20-2017 11:00 AM

Greetings,
Mr. O. Holy crap! She looks GREAT.

Pack Mule 02-20-2017 11:05 AM

This boat looks familiar. Wasn't the previous owner here on TF ?

Xsbank 02-20-2017 11:48 AM

Gorgeous! She looks to be well-cared for. If you are so inclined, more photos?

Britannia 02-20-2017 11:50 AM

For reference Stillwater is powered by a JD 6068T (6.8l/225HP) with a 2.93:1 ratio and turns a 34" prop. No stalling of course.

Richard

Britannia 02-20-2017 11:54 AM

Quote:

Originally Posted by Britannia (Post 525448)
For reference Stillwater is powered by a JD 6068T (6.8l/225HP) with a 2.93:1 ratio and turns a 34" prop. No stalling of course.

Richard

Oh and I love the look of her to be sure! Very similar design of hull to mine (except the steel!.)

Sailor of Fortune 02-20-2017 12:01 PM

Is she a Sutton shipyard build?

DavidM 02-20-2017 12:02 PM

That sure looks like a DD 671 powered trawler to me.

Post the entire oil analysis. Ski can give you some pointers.

A new Cummins 6C reman will cost at least $30,000 with transmission. You will benefit from better fuel consumption (18-19 hp/gph vs 16), less noise, no oil leaks and a new engine warranty. Is that worth it to you?

You can use tractor, construction or over the road diesel and assuming you currently have keel cooling and dry stack exhaust you can probably cobble together something for 1/3 of the above. It will not have a water cooled exhaust manifold however. That is a big negative for me, but lots of others say they are fine.

If the current 671 is really trashed, I think I would go that route.

David

Sailor of Fortune 02-20-2017 12:03 PM

I think packmule is right, her posts was here.( PO not posts) previous owner.

Pack Mule 02-20-2017 12:04 PM

Quote:

Originally Posted by Sailor of Fortune (Post 525453)
I think packmule is right, her posts was here

I'm thinking it was BryanF.

Obie 02-20-2017 12:10 PM

No she is in Astoria oregon

Obie 02-20-2017 12:25 PM

I am so exited about this girl. I just found her 3 days before I was leaving town for 10 days to mexico, so i have had very little time with her so fare. It had to be a quick cash deal, no waiting. But she has a good ultrasound Servay of the hull, all the little pits were welded up, and she was striped to white metal and painted. Hull is great! The feast? But what a great platform. She has 5 water tight compartments, plenty of fuel. Water tankes are 2 450 gallon, total 900. I want to cut them out and install 2 200 gallon SS.

Obie 02-20-2017 12:31 PM

TF, ok trawler forum, got it! I want to find that thread. Poor guy, had his dream then heart atack at 62, not OK.
Go now don't wait!

Sailor of Fortune 02-20-2017 12:33 PM

Why would you consider cutting out the original tanks and SS is hardly an ideal material for fuel tanks. As long as the originals have cleanout/inspection ports, I would stay with them.

Obie 02-20-2017 12:37 PM

4 Attachment(s)
Pics

Obie 02-20-2017 12:39 PM

No just for the water tanks. She has 8 fuel tankes, all with great inspection ports.

Mako 02-20-2017 12:58 PM

Hey Obie, she's fantastic in every way except one... those anchors! Perhaps you should ask the people here their advise on that, they are always so friendly and helpful when it comes to anchor-talk :popcorn:

RT Firefly 02-20-2017 01:07 PM

Greetings,
Mr. O. IF I may suggest a method of getting to know your new girl...STOP. Make NO plans for at least 6 months. What seems like a good idea now may not be so in the future. Make no changes unless absolutely necessary. I really know what you're going through and the excitement you are experiencing. Been there, done that, three times already. I'm not trying to pee on your pancakes at all but like getting to know ANY woman/mistress, it takes time to establish and develop a good relationship.
When you get back on her, find a comfortable place, a comfortable seat, put on some good music (keep it low key...You know you always drive faster when a fast tune is on the radio? Don't want that. Not right now) and chill. For the moment, just forget about changing her. Enjoy her vibes and relax...

https://media.giphy.com/media/dAZil1oVwZDNe/giphy.gif

Nightsky 02-20-2017 01:09 PM

Quote:

Originally Posted by makobuilders (Post 525481)
Hey Obie, she's fantastic in every way except one... those anchors! Perhaps you should ask the people here their advise on that, they are always so friendly and helpful when it comes to anchor-talk :popcorn:

You are such a ship-disturber. :rofl:

Obie 02-20-2017 02:24 PM

Good advice, except she is part way into a bit of a refit. Like you I have done this a few times, more than I would cair to admit. For me it is looking at what is there and simplify, simplify, simplify. This girl has 4 electrical systems. 120 shore power, 220 from transformer, 32 volt, engine refrigeration, autopilot, inverter, and more. 12 volt depth, some lighting. She has more valves and through hulls, than any boat should. Two water systems, two hot water heaters. 1 220 volt one propane. Time to simplify.
Obie

Hamrow 02-20-2017 02:49 PM

Obie,
that's a beautiful salty boat, congratulations on your purchase! You probably know hull speed for that waterline should be right at 9 kts. A repower should likely be a choice of minimum horsepower needed to comfortably move your tonnage along at hull speed.
If you're going to use her a lot, i can understand why you might want to improve your GPH. good luck!

sunchaser 02-20-2017 03:49 PM

Quote:

Originally Posted by djmarchand (Post 525452)
It will not have a water cooled exhaust manifold however. That is a big negative for me, but lots of others say they are fine. David

All sorts of already marinized options for coolant cooled exhaust manifolds while using a dry stack setup. Certainly not from an over the road truck though, just have to find a marinization setup kit, which isn't always easy..

Xsbank 02-20-2017 03:53 PM

I am in the middle of refurbishing my water tanks, I cut a hole in the deck and installed a hatch and I'm busy scrubbing, scrubbing and intend some sterilizing chemical and some more scrubbing. Your water tanks may be recoverable and are probably part of the hull anyway...

Gorgeous boat. If you have to repower will you do it through the side of the hull?

Xsbank 02-20-2017 03:58 PM

Not sure what the concerns are over a dry exhaust? You just wrap it with a blanket or use a custom-made jacket. Easy and no worries. My exhaust is cool to the touch, most of the engine heat is from the block itself. Keep the saltwater out and there is no limit to how long the engine will run dry stacked.

My exhaust was a long blanket that you wrap with aluminum tape, cost me about 200 for the kit. You will need more tape than they give you if the exhaust is convoluted, buy a spare roll of tape, it doesn't go bad and is useful for repairs. You can double-wrap the turbo and it will be cool enough to sleep on.

kchace 02-20-2017 05:07 PM

Quote:

Originally Posted by Obie (Post 525472)
Pics

THAT is a real boat!. Wouldn't mind one like that.

Ken

Sailor of Fortune 02-20-2017 05:40 PM

FG wrap tape, Chill seal painted on makes it cool to the touch. Blanket on top if you want. Standard setup for thousands of boats worldwide. If you want to KISS your systems , this is a big one.

Nomad Willy 02-20-2017 05:56 PM

Quote:

Originally Posted by Obie (Post 525424)
Just a few pics, I think she is around 50 ton.

Obie,
225hp would be 4.5hp per ton. Should be perfect.

Obie 02-20-2017 06:24 PM

No there is a huge access hatch over the engine room. Even a large crane that drops straight in. That is so easy.

Sailor of Fortune 02-20-2017 06:45 PM

Nice boat!!

Xsbank 02-20-2017 08:15 PM

She's gorgeous, Obie! Will you marry me? Oh, wait....

Pack Mule 02-20-2017 08:20 PM

Nice boat Obie .

Obie 02-20-2017 08:38 PM

xsbank
LOL
I just saw that you have a 52 foot aluminum boat, nice. I have a 37 foot aluminum sailboat also. I like metal boats. I will probably put a full blown isolation transformer in my new one. First thing I did with my aluminum one.
Obie

markpierce 02-20-2017 09:11 PM

Aaaahhh! Keel-protected propeller and shaft!


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