repowering my sailboat- engine selection

[DeValency]

Get a Yanmar 2GM or a Beta Marine (harder to get but a great engine). Yanmar can probably be found used in a good shape and you’re all set. You will need to set new mounts etc. nothing that a good boatyard guy can’t do within few days. Of course all the accessories around - water intake, cooled muffler, u elbow control panel, diesel tank (if you don’t have one). Can be found used for this size.
Best of luck

[StuartWeibel]

I re-powered my 6,000 # 26' wooden gaff cutter with a Beta 14 (13.5 HP). It will drive me at hull speed, and cruise comfortably at 75% throttle at 5.5 knots in a neutral sea. I sail the inside passage, Seattle to Alaska... lots of tidal gates and big currents. The improvement over my 1GM10 is substantial.

I wrote an extended blog post on the process and snags, found here:
Re-powering s/v Ripple

[Robert Jansen]

Why not consider dragging yourself kicking and screaming into the 21st century and install a hybrid system? It will be much more energy efficient, and you'll get a genset and upgraded battery banks at the same time.

[Dave9111]

This is a $1000 boat which might sell for $5000 if he installs a marine diesel.
He is losing money unless he doesn't care about the resale.

You say you don't like gas engines in boat? So that rules out Atomic4s which are about the cheapest marine engine you can get and maintain.
If you want to go with a small diesel and can find one cheap, then go for that. 20-25 hp is not too big. If it runs at 1/3 load, that's not a problem.
Beta Marine engines start at about $8000 and go up from there. If you have a 50K boat, then that might make sense, otherwise no.

[Adelie]

Originally Posted by SteveSadler

Hey Mike Thats a little harsh advise for a guy who is asking advise on a forum.
You're also wrong about sailboat hulls being designed for in or out motors. Either will work if it can be installed. However a laser may not have room for an inboard. Go sailing!

[emoji106]

[Shaneesprit]

Originally Posted by a64pilot

Your a Diesel Mechanic, so you will know that a little oversized won’t harm anything.
In truth you could put my 44 HP Yanmar in there and it would not hurt the motor, but it wouldn’t likely fit and it would likely overload the boat due to its weight.
I’d worry more about what fits and still gives you room to work on the thing and what it weighs.

Not True - oversized engines are damaged by not being used hard enough, its not water Temp that matters its cylinder / Piston temp that you cannot measure
causing Glazing of the bores, and you end up with diesel in the engine oil,
Engine loading needs to be average 70% or at least the ability to run under heavy load for an hour or 2 as this will clean up the engine internals - not the oil the only way to get diesel out of the oil is to change it and the only way to know if its there in the first place is to have a sample tested.

you know those car drivers who say their car never uses any oil, well oil gets used just that its being replaced with something else like the fuel.

[Suijin]

Originally Posted by Shaneesprit

Not True - oversized engines are damaged by not being used hard enough, its not water Temp that matters its cylinder / Piston temp that you cannot measure

causing Glazing of the bores, and you end up with diesel in the engine oil,

Engine loading needs to be average 70% or at least the ability to run under heavy load for an hour or 2 as this will clean up the engine internals - not the oil the only way to get diesel out of the oil is to change it and the only way to know if its there in the first place is to have a sample tested.



you know those car drivers who say their car never uses any oil, well oil gets used just that its being replaced with something else like the fuel.

This is nonsense.

Truckers would not leave their diesels idling for hours on end. Heavy machinery operators would not either. If it’s a turbo, yes it needs to be run hard after a period of low load but that’s not your normally aspirated diesel.

I have a friend, an ex merchant marine diesel engineer who not so long ago finished a 15 year circumnavigation on a Yanmar he installed himself, his only means of charging. He had 11,000 hours on it. Said half of that was probably idling.

So long as it comes up to operating temp it’s going to be fine. Prop it correctly and you’re good.

[DeValency]

So I guess your friend is the authority in marine diesels as the other irrelevant examples you’ve mentioned. I can only recommend reading some engineering data and literature on diesel cylinders glazing issues and the strong recommendations of any Diesel engines manufacturer and experts to keep the engines loaded as much as possible.
Here is a good start: https://www.powerandmotoryacht.com/m...l-engine-myths

Now, about the examples you’ve mentioned: trucks and industrial machinery are not using free ocean/lake water but a closed cooling system that uses radiator as an air heat exchanger vs. continuous cold water intake to the heat exchanger (or direct) in boats. So trucks can control better the working temperature as radiators are keeping a higher temperatures and you can see how truckers are using radiators covers to restrict cold air from lowering the coolant temperature while idling. It is still a bad practice but they have their own issues to deal with and no generators or battery banks.

I’m an engineer and a sailor for over 30 years but no one need such background to understand this phenomena. Basic reading is good enough as well as some respect to the former professional comment.

QUOTE=Suijin;2816175]This is nonsense.

Truckers would not leave their diesels idling for hours on end. Heavy machinery operators would not either. If it’s a turbo, yes it needs to be run hard after a period of low load but that’s not your normally aspirated diesel.

I have a friend, an ex merchant marine diesel engineer who not so long ago finished a 15 year circumnavigation on a Yanmar he installed himself, his only means of charging. He had 11,000 hours on it. Said half of that was probably idling.

So long as it comes up to operating temp it’s going to be fine. Prop it correctly and you’re good.[/QUOTE]

[kvstein]

Getting away from the technical aspects of this thread: Remember what the great Johnny Cash once said. " What do you get when you put $1000 into a $1000 dollar car? A $1000 dollar car." So what do you get when you put a $8000 dollar motor (no labor) into a $1000 yacht? A $1000 yacht. Just sayin.

[RUSTYNAIL]

I've had good luck with Beta engines, just ask the company, and they'll tell you what size is required. They are set up with most everything you need after you install the shaft.

[DeValency]

Originally Posted by kvstein

Getting away from the technical aspects of this thread: Remember what the great Johnny Cash once said. " What do you get when you put $1000 into a $1000 dollar car? A $1000 dollar car." So what do you get when you put a $8000 dollar motor (no labor) into a $1000 yacht? A $1000 yacht. Just sayin.

Haha - Johnny Cash is one of my favorite artists ever and he was right on that as well, but this isn’t the proper analogy for this case.

- all cars must have a fully working engine. Not all boats.
- the OP, paid $1K for a Catalina 27 with no engine and probably other issues. I guess the real value of such a boat that has everything (including a diesel) in proper condition is maybe $8-10K in today’s market?

- he can get a used 1GM or 2GM or Beta for about 2-3K and if he is capable to do some DIY and has a cheap/friendly boat yard to help can get it all done for another $3K or so and enjoy a really nice boat for a long time - this scenario is quite risky financially and I wouldn’t do it in today’s market where 35+ years old well maintained boats under 30’ are flooding the market almost at any buyer’s price. If he is a trader, this is of course not a great deal.

- or he can just get a boat, already fully installed and in a good shape for $8-10K

His call and interest... but I guess most of us are sailors not boat traders...

Personally, I’m on a totally different range of purchasing and refitting, but I’ve done that with my first keel boat, 25 years ago: Dufour 24 that I bought for $7K, installed a new Yanmar 2GM plus a massive refitting for a total cost of $10K and sold her after 6 months for $25K. The guy who bought that boat still keep her and cruising with her all over the Med(!) and he still tells me he is extremely happy! - and so do I...

Anyway, good discussion here. I believe the knowledge gained here from all the others, for the OP now worth more than his boat...

[a64pilot]

Originally Posted by Shaneesprit

Not True - oversized engines are damaged by not being used hard enough, its not water Temp that matters its cylinder / Piston temp that you cannot measure

causing Glazing of the bores, and you end up with diesel in the engine oil,

Engine loading needs to be average 70% or at least the ability to run under heavy load for an hour or 2 as this will clean up the engine internals - not the oil the only way to get diesel out of the oil is to change it and the only way to know if its there in the first place is to have a sample tested.



you know those car drivers who say their car never uses any oil, well oil gets used just that its being replaced with something else like the fuel.

No, it doesn’t need to be anywhere near 70% and there is a lot of evidence that if an engine is run almost continuously at lower power settings, they last many times longer than one run hard continuously.
What you are talking about is called Slobbering or stacking, and the US Army commissioned a study years ago and couldn’t find that it was harmful, it’s undesirable, but not harmful.
https://apps.dtic.mil/dtic/tr/fulltext/u2/a151273.pdf

However we aren’t talking about high idle, low load, we are talking about lighter loads, but still enough for the engine to reach full operating temp.

[a64pilot]

The concept of having a little extra power isn’t necessarily about exceeding hull speed.
My boat when I run it at 1800 RPM will make about 6.5 kts with a clean hull in smooth water, however put her into a 30 kt headwind and with the accompanying seas and she slows to 3 kts, sometimes less.
Bump the throttle to 2500 RPM and she will make 5 kts, and increase of only about two kts, but pretty much double the speed she was making.
I’d rather not run her at 2500 continuously, much less higher.
If I had a little larger motor, I wouldn’t have to.

So it’s not necessarily about exceeding hull speed, sometimes it’s about continuing to make way, without having to run the motor harder than I like to.
One thing is at higher RPM it sounds like someone is mowing the lawn in my Salon, and I don’t like that much noise.

[Dave9111]

Most marine engines don't die from being "worn out", they die due to internal and external corrosion and the lack of maintenance (winterizing etc).
How many people do you know who have worn out a sailboat diesel engine? It almost never happens.

How many people know of diesel engines which locked up due to lack of use? Lack of winterization. Corrosion. It happens all of the time.

Consequently the idea that a boat engine will last for 8000 hours if run at 3/4 load vs 5000 hours if run at 1/3 load is pretty much irrelevant.



For a $1000 boat, unless I was going to cruise with it extensively, I would either go with an outboard, or go with a gas Atomic4. Boat diesels cost way too much money.


Depending on the situation, I would also consider going with an adapted Honda/clone gas air cooled engine with a wet exhaust. That could make a lot of sense if the boat lives on a mooring (less need for reverse). Is usually sailed and motoring is only used to get back home when the wind dies. Another idea is to use a gas air cooled engine, and make up your own hydraulic forward/neutral/reverse setup.



I sail solo most of the time, so when I am docking or departing, I am in the cockpit dodging boats, releasing lines, etc, if the engine is noisy down below, I really don't care as I am not down there.

That said, some of these solutions would kill resale value, but lets face it, a $1000 sailboat won't be a moneymaker in any sense unless it was bought for way less than market value in the first place. So IMO, this is all about minimizing costs and not about resale value.

[Jim Cate]

Did most of you read the original post? The OP is a pro mechanic, works in a boat yard, the boat is on the hard there at low or no cost. He has experience and skills and tools to do the job... AND he just wants to do the conversion to a diesel. It isn't an unreasonable goal, for Catalina did offer the boat with a small (14hp?) diesel installed... so why all the bashing?

He does not need advice about the economics of his project or what other alternatives could be used. His question is about engine power and engine choice. The consensus is that around 20 hp would work quite well, and would not suffer from unloaded usage. Small Kubota conversions or small Yanmars are suggested. Sounds OK to me!

Instead of telling him why he is wrong to do the job, those with the knowledge should be offering advice on getting it done. I lack that knowledge, but can offer support... and perhaps help ward off the bashers!

Jim