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Old 22-09-2010, 00:51   #1
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Cost / Value of New Diesel Refit ?

Many of the boats I'm looking at seem to have underpowered diesel engines, and based on the age, I'm considering budgeting for a new more powerful engine. First of all, does this make any sense if I plan to keep the boat as a blue water liveaboard for several years or should I just try and run with the stock engine and risk something going wrong and struggling with power and an undersized motor?

How much is a ballpark to do this? I realize there are many variables depending on size, but how much more to it is there than just replacing the motor? I'm guessing size inside the cabin but I suppose there are transmissions and shafts to worry about? Is this a dumb idea?
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Old 22-09-2010, 01:18   #2
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Smaller engine if anything. A blue water liveaboard has little need for speed or schedules. If you had said coastal freight service I'd say get a more powerful engine.

Blue water means you'll be sailing most the time because it will be too far to motor. Liveaboard means it's okay if you go backwards some days. I reduced an engine from 30 to 20. That was on a boat that had to do the Baja Bash annually. Worked out fine. Went quite slow some days. But who cares? I didn't.
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Old 22-09-2010, 09:47   #3
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I agree with Daddle. If you don't mind, I'm going to include a rather lengthy quote from Jim Brown because I think he said it best and I'm re-editing the Searunner Construction Manual. Now, there are a number of ways where technology sort of helps us get around the below problems but only insofar as the technology doesn't fail.

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I’m not going to offend you with a list of all the ancient - and modern - circumnavigators whose achievements were made without engines. There is no parallel between Magellan or Hiscock and me or you. The feats of seamanship involved in an engineless sailboat are certainly more demanding, and more satisfying when achieved. And certainly more embarrassing when not achieved.

But NOT more dangerous! Certainly not. Anyone who argues for an engine on the basis of safety is missing the mark. Except in one instance - man overboard. Retrieving a sailor who has left the boat before arriving in port is the best single excuse for having an engine on the grounds of safety. Even then, the crew on board may have a better chance to return for the castaway if they can hear him - hear the whistle he should have sewn into the pocket of his lifejacket or tied onto the lanyard of his knife, always at hand. Lacking the convenience of the engine, the crew is perhaps better prepared to maneuver the vessel for pickup - because of man overboard drills that might not have been practiced had they an engine to rely on. And the possibility of falling overboard will be perhaps more omni-present in the minds of a sailing crew and so it may be thereby prevented. Still, an engine will be useful in such times of emergency, if it works.

Engine failure, in an insidious way, often causes danger of greater consequence than no engine at all. Boat engines are more prone to failure than any other type - especially these “amateur” installations. The marine environment is hard enough on deck hardware, made of bronze and stainless, but the engine is all ferrous metal. Whether fresh-water cooled via heat exchanger, or seawater cooled, a marine engine has an electrolytic contact with the ocean which causes corrosion as fast as granite dust eats up a tractor motor. Add to this the notoriously dirty fuels available at dockside and the difficulty in maintaining boat motors because of space limitations, the long periods of disuse interrupted by spurts of “lugging all the time” (a marine engine never lets up or runs downhill) and you have a brief explanation of why boat motors have lots of problems. Just like with automobiles, gasoline boat engines suffer most from electrical problems: battery charge and ignition. Here the diesel is singularly different because it has - theoretically - no ignition system. But diesels are often equipped with glow plugs for starting and are even more dependent on the battery for starting because their hellish compression ratios make even the small ones almost impossible to hand crank. And, while the diesel has no spark plugs, wait ‘til you try adjusting fuel injectors or bleeding air from lines at sea! If you run a diesel out of fuel or cause the tank to deliver air to the fuel line - perhaps from the churning of heavy weather - better get the oars warmed up unless you really know how to sail.

...

I can hear the moans of disagreement now. “He’s crazy” you’ll be saying. “Nobody could sail in and out of my harbor. I can’t sail to work on Monday morning after an all-night Sunday calm and so I’ll force myself to do without the engine except when there is no alternative.”

Very well. That’s what engines are for. But watch yourself. Watch yourself putting the cover on the mainsail while motoring past the jetty, and watch yourself struggling to get it off when the engine quits.
If you end up on the rocks will it be because the engine failed? Or will it be because you wouldn’t have attempted to enter past that jetty under those conditions without an engine? Or will it be because your reliance on the engine insidiously kept you from learning to sail past that jetty under those conditions?

And watch yourself when you secure the halyards - to keep them from flapping on the mast while anchored in a tight cove with a rubble bottom and a rising wind and a falling glass. If the anchor drags you’ll just motor up and drop it again. Except that somebody left the refrigerator door open and it drained the “accessories” battery so someone switched to the starting battery and still the refrigerator door is open because the latch is faulty or the beer shifted so it won’t close or any of a thousand things that could leave you engineless and halyardless and dragging onto the rocks. Great safety feature, those engines.

Silence is golden and sails are quiet. Watch yourself motoring right up onto the beach in a fog because you couldn’t hear the surf. Picture you, at the helm, blinded by cabin lights which the crew burns freely while the motor is charging. You couldn’t see the tiny lantern and you couldn’t hear the shouts. It was a quiet Bahama night and you drove smack into a quiet Bahama smack, its crew enjoying their repose and their conch chowder while you came deafly upon them borne by a gasoline breeze.
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Old 22-09-2010, 10:11   #4
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And I'd totally disagree with daddle. Bear in moind that bluewater means you will be at sea in all conditions, and every offshore "racing authority" has a requirement for an adequate engine and typically 48 hours worth of fuel for it, so you can propel the boat in sustained storm conditions.

The engine that the boat was built with was chosen for price--but also for reasonably adequate performance. You'd need to evaluatre what it can do, versus what you really will need to do, and consider whether re-propping might be part of the solution.

A replacement engine is going to be expensive, and you will never recover the cost of it. Even if you do all the labor yourself--it will be expensive. Typically, $12-20,000 for a diesel.

If the builder chose to install the 'wrong' engine for your intended purposes, the odds are that's not all that is 'wrong' about that boat. It might well be simpler and cheaper to re-evaluate the boat, and consider replacing it with one that was built "right" for your purposes in the first place.

For instance, you can add tankage to any boat, but a bluewater boat will sit properly on her design water line, WITH all that extra weight built in. A converted daysailor? Will be sitting too low, and there's no good way to cure that.
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Old 22-09-2010, 19:57   #5
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As the previous poster said, do not intend on the engine "adding value"

When "up-powering" there are things that need to be considered.

Access to engine componenets, need to rebuild engine bed if needed.

Most importantly but many times over looked is the exhaust.

I worked in a boatyard and they were repowering a boat with a Larger engine.....I told them that they needed to match the exhaust line to the
exhaust outlet......They didn't want to run a new exhaust line...it would be too hard and would require some wood work due to the "run"...so they
just put in a reducer.....the boat smoked and ran like crap.

I was given the "honour" of making it right.
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Old 22-09-2010, 20:23   #6
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Quote:
Originally Posted by SS Little-Devil View Post
Many of the boats I'm looking at seem to have underpowered diesel engines, and based on the age, I'm considering budgeting for a new more powerful engine. First of all, does this make any sense if I plan to keep the boat as a blue water liveaboard for several years or should I just try and run with the stock engine and risk something going wrong and struggling with power and an undersized motor?

How much is a ballpark to do this? I realize there are many variables depending on size, but how much more to it is there than just replacing the motor? I'm guessing size inside the cabin but I suppose there are transmissions and shafts to worry about? Is this a dumb idea?

Yes, if you go up enough you may need a new shaft, which means new couples, packing gland, possibly a shaft log, cutlass bearing, strut and prop. Double all that for a catamaran!

You will also be using more fuel, so you will have a shorter range assuming you don't add more tankage.

Mike
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Old 22-09-2010, 21:08   #7
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I will leave the not,s, rather's and where-for's to others with more experience the I.

My only comment will be.

Why go New?

If my Perkins ever tanks...Im going to rip out some diesel out of one of my pieces of equipment that makes me 150.00 per hour and put the new motor in that...then put the perfectly good used one that's still making me 150.00 per hour in the sail boat.

You can do the same thing...it will be a tougher and riskier proposition for you then I as I know my engines... but if you take the time to really find someone with some integrity to deal with it should be almost as risk free.

99.9 percent of marine diesels are marinized truck or tractor engines...marinizing them is not rocket science....you should be able to re-power any sail boat under 70' for less the 5K....often a 100 horse engine will be less money then a 30 horse one...just because of supply and demand as to the industry they came from.

As an examlpe...I have 4 engines sitting ready to go...the big 6-71 Jimmy would be the cheapest of the lot...probably runs the best too...........anyone wanting to build an LCM...
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Old 22-09-2010, 21:30   #8
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the big 6-71 Jimmy would be the cheapest of the lot...probably runs the best too...........anyone wanting to build an LCM...
Anyone really want to listen to one?!?!?!?! I have a serious love hate with the 53/71/92 series of droolers.
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Old 22-09-2010, 21:35   #9
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Anyone really want to listen to one?!?!?!?! I have a serious love hate with the 53/71/92 series of droolers.
Im with you there!....but on a BIG boat like a LCM...sound insulation is not an issue.

FWIW...I also have a 6v-92...I have managed to get the air boxes drip free....it runs cleaner then either my 350 big cam or my 444 Cummings....it is possible it just takes effort.
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Old 22-09-2010, 22:24   #10
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Quote:
Originally Posted by SS Little-Devil View Post
Many of the boats I'm looking at seem to have underpowered diesel engines, and based on the age, I'm considering budgeting for a new more powerful engine.

First of all, does this make any sense if I plan to keep the boat as a blue water liveaboard for several years or should I just try and run with the stock engine and risk something going wrong and struggling with power and an undersized motor?
Start by defining underpowered.

The old rule of thumb was 1hp/1000lb which would generally give you 2kt boat speed staight into 20kt winds with a 2nm fetch. If you are going cruising that probably is a reasonable number.

If you will be mostly weekending and need to be back on time and expect to regularly have to go hull speed bashing your way home into 25-30kt then more power might be needed. Or you could motorsail with the smaller engine and do almost as well.

I personally would follow the old rule of thumb (adding several thousand pounds extra in the calcs for fuel, water, provisions and crew items). The weight saved going with the smaller engine could go into a larger fuel tank giving longer range. The smaller engine will also be happier motoring in the 3-5kt range giving you even better fuel economy. Offshore I would rather have range than power.
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Old 23-09-2010, 06:52   #11
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I reckon Oh Joy doesn't fit that theorem. She has a Perkins 50 and weighs in at a svelte 14,500. Of course, at full throttle, that big Perkins will drive her up on the bow wave and bury the transom. Kinda funny to pop a wheelie in a sailing yacht but a waste of weight. I only had to use all of that power once to claw off some rocks in 60+ at Point Wilson but at least I could go to windward when the ferry couldn't....
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Old 23-09-2010, 08:50   #12
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I think Daddle and Marens replies were right on the mark. I don't want to start another electric vs. diesel debate. But, you might want to take you take a look at electric propulsion as a replacement for your diesel. I replaced my Westerbeke 27 diesel three years ago and would never go back to having a diesel onboard.
You should see the grin on my face when under sail and making "fuel" at the same time.
My boat is 16,000 pound 30 foot catboat and in three years and in almost a thousand miles of cruising my maintenance cost have been about $5.00 for the oil change for the Honda generator. I did most of the install myself and feel this system will be much more reliable and cheaper to operate than my diesel ever was. Yes, you will not be going five knots for 48 hours straight while listening to a diesel engine. But moving along at 3-4 using and Honda 2000 works for me while I wait for the wind to kick up.
Plus with my windgenerator and 48 volt solar panels the boat makes energy for the propulsion system while at anchor too. Can't do that with a diesel! I am not against diesel but, I think they are a bad fit in a cruising sailboat. No pun intended! But, I for one am glad I don't have to squeeze my 6 foot two inch frame under the cockpit anymore to do even routine maintenance like I use to do on with the diesel. All I can say electric propulsion works for me and I'm so glad I made the switch.
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Old 23-09-2010, 08:56   #13
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Quote:
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The old rule of thumb was 1hp/1000lb...
When was that the rule of thumb? Or was that an "absolute minimum" sort of rule of thumb?

What I have always heard as the rule of thumb for a good sized diesel for a sailboat is 2hp/1,000lbs. You can do okay with a little smaller. You might want to go a little larger. But something in that neighborhood will power your sailboat well and allow you to power into moderate winds and currents.

Most production boats nowadays have an engine that is in that ballpark. My experiences with motoring on such boats, as well as on boats with significantly larger and smaller engines, would tell me that it is a pretty good rule of thumb.

To the OP: I very rarely see boats for sale that are significantly underpowered. Indeed, boats that are overpowered are much more common. I have to wonder what sort of rule of thumb you are applying to come to the conclusion that many of the boats that you are seeing are underpowered. If you are comparing sailboats to trawlers, for instance, you might come to such a conclusion, but it would be a serious mistake to make that sort of comparison.
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Old 23-09-2010, 09:10   #14
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You are right the engine has to breath when I up graded with a larger engine in my boat I went 1/2 inch over the exaust size for the long run of the exaust line it has performed great never under size back preasure on the engine is not good
Quote:
Originally Posted by Chief Engineer View Post
As the previous poster said, do not intend on the engine "adding value"

When "up-powering" there are things that need to be considered.

Access to engine componenets, need to rebuild engine bed if needed.

Most importantly but many times over looked is the exhaust.

I worked in a boatyard and they were repowering a boat with a Larger engine.....I told them that they needed to match the exhaust line to the
exhaust outlet......They didn't want to run a new exhaust line...it would be too hard and would require some wood work due to the "run"...so they
just put in a reducer.....the boat smoked and ran like crap.

I was given the "honour" of making it right.
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Old 23-09-2010, 09:29   #15
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new engine

Quote:
Originally Posted by SS Little-Devil View Post
Many of the boats I'm looking at seem to have underpowered diesel engines, and based on the age, I'm considering budgeting for a new more powerful engine. First of all, does this make any sense if I plan to keep the boat as a blue water liveaboard for several years or should I just try and run with the stock engine and risk something going wrong and struggling with power and an undersized motor?

How much is a ballpark to do this? I realize there are many variables depending on size, but how much more to it is there than just replacing the motor? I'm guessing size inside the cabin but I suppose there are transmissions and shafts to worry about? Is this a dumb idea?
when i put my new engine in i bought it from surplus center.com great deals on engines there i had to marinize this cat engine which was'nt hard to do and another thing rebuilding a old engine whats going to break next ? my old perkins was going to 2 and 4 hundred dollar me to death i bought a larger engine marinized it chaeper than i could rebuild the old smudge pot and its new with warnty always fires right up sweet and snooth even with 27 cubic inches larger i get better fule econamy and much more power i regeared and run at lower rpms to me new is the only way to go
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