Re-power

[Tommee]

I have a Hans Christian 43T ketch & am thinking about replacing the BMW D50-2 engine. At 41 years old it's getting tired!! I have been looking at the Yanmar 4JH57. Does anyone have any experience with this engine, would it be a good replacement?
Quiet One is 18 tons, long keel & I had wished for a larger engine but may not have room or $$$. The BMW has a Hurth gearbox with ratio 3:1 & has always been a low revving engine. Are the Yanmars too high revving for this heavy displacement? All comments much appreciated.

[SailingHarmonie]

There is no issue with the engine speed and the boat type. If you can turn a prop of the right diameter, the shaft speed really does not matter. A prop of shallower pitch will work as well with a higher shaft speed.

A modern higher speed engine will be more efficient than an older slower turning one. Lighter, and smaller too for the same power output. Most engines in sailboats die from neglect LONG before they “wear out”.

[skipperpete]

I know that the 4JH series will physically fit, a forum member with a 41T pulled one out of his HC and repowered it with a Betamarine (60 I think). I rebuilt a Lehman peugeot from a HC , bugger all room under the galley to do much in situ but the skylight made it easy to extract from the boat.
I’m not a big fan of common rail diesels for global travelling, when they stop, it’s not easy to diagnose and repair electronically controlled engines far from dealerships…. But ok for coastal and local cruising where dealerships abound.

[Tommee]

Thank you for the info, appreciated.

[Tommee]

Totally agree, was hoping to avoid complicated engines & definitely anything Turbo charged. I had some specs come back from the Yanmar agency giving HP loss due to various reasons ie 1.7hp loss per shaft bearing. I have 3 of these, cutlass bearing, stern gland with packing box & hangar bearing. In your opinion would the Yanmar 57hp be slightly more powerful than the BMW 50hp? Can't be doing with less power thats for sure, morte would be better, but it seems larger engines get into the Turbo phase & might not fit. As you mention the under galley arrangement leaves little room for bigger.

[skipperpete]

You won’t be able to get 3:1 reduction with the 4JH57 the available ratios vary from 2.15:1 up to about 2.4:1 with one of the down angle options of 1.47:1. Yes you’ll have more power and don’t take Yanmar too seriously over the prop shaft losses. The turbo engines aren’t really any larger, the turbo’s on the back of the engine so the mixer comes out a bit further to the side but apart from that , about the same as the non turbo …….until you get up to the intercooler versions.

[Tommee]

Thank you Skipper Pete.

[RaymondR]

About 10 years ago I decided to re-engine my boat because the original engine, a Yanmar 3GM30, was to small for the boat. Easy peasy, I'll just wander over to the Yanmar dealer and pick up a 50 or so HP job. Shock horror, whilst I knew that the basic engine under the mass of tinny looking addons was probably a fine piece of engineering the thought of having to replace the tinny addons regularly soured me of the whole idea. So I went and bought a Kuboto V2203 industrial engine, which I marinised, and a Twin Disk gearbox and put them in.

There's a lot to be said for those old simple diesel engines (with purely mechanical fuel systems) that can be left neglected in a boat.

[TrentePieds]

Tommee:

If you really must repower, then the only thing left in the boat from the old installation will be the prop shaft. :-)

But have you misread the specs? A HC33T does not displace 18 TONS, but rather 18K POUNDS, i.e just over EIGHT tons. Or was the 18t just a mistype :-)?

For an 8-tonner (call it 10t laden) modern convention would call for 4 x 10 = 32HP. Therefore, your BMW should have plenty of oomph. If the beast "feels tired", you should probably look for a reason implicit in your present actual installation before you incur the great expense of an engine swop.

Tell us why you say that your present engine is "getting tired"? What are the actual manifestations of that? Engines in sailing yachts tend to die from mishap or neglect rather than wear.

All the best

TrentePieds

[Cheechako]

Originally Posted by Tommee

I have a Hans Christian 43T ketch & am thinking about replacing the BMW D50-2 engine. At 41 years old it's getting tired!! I have been looking at the Yanmar 4JH57. Does anyone have any experience with this engine, would it be a good replacement?
Quiet One is 18 tons, long keel & I had wished for a larger engine but may not have room or $$$. The BMW has a Hurth gearbox with ratio 3:1 & has always been a low revving engine. Are the Yanmars too high revving for this heavy displacement? All comments much appreciated.

Select the HP you want at the RPM you want from the new engines available. If possible buy the non Turbo type.
In other words; If you need 50 hp, buy an engine that puts out 50 HP at the rpm you want it to. Especially with lightweight high RPM rated engines.

If possible I would try to find a non "common rail" engine.

[Cheechako]

Originally Posted by TrentePieds

Tommee:

If you really must repower, then the only thing left in the boat from the old installation will be the prop shaft. :-)

But have you misread the specs? A HC33T does not displace 18 TONS, but rather 18K POUNDS, i.e just over EIGHT tons. Or was the 18t just a mistype :-)?

For an 8-tonner (call it 10t laden) modern convention would call for 4 x 10 = 32HP. Therefore, your BMW should have plenty of oomph. If the beast "feels tired", you should probably look for a reason implicit in your present actual installation before you incur the great expense of an engine swop.

Tell us why you say that your present engine is "getting tired"? What are the actual manifestations of that? Engines in sailing yachts tend to die from mishap or neglect rather than wear.

All the best

TrentePieds

The OP's boat is a 43 foot.

[TrentePieds]

Ah, yes - my mistake. Forgive me :-). What's I've said nevertheless applies mutatis mutandis.

The 43-specs say 15 tons displacement, so 18 is probably right in cruising trim:-). The BMW may well be a little on the skinny side then :-).

Taking your advice, Cheechaco, a Beta75 would seem to be appropriate. That should give about 65HP at 2,100 RPM. I would think that would be livable :-)

I think the bob-tail engine is about US$6K.

TP


I

[Cheechako]

Originally Posted by TrentePieds

Ah, yes - my mistake. Forgive me :-). What's I've said nevertheless applies mutatis mutandis.

The 43-specs say 15 tons displacement, so 18 is probably right in cruising trim:-). The BMW may well be a little on the skinny side then :-).

Taking your advice, Cheechaco, a Beta75 would seem to be appropriate. That should give about 65HP at 2,100 RPM. I would think that would be livable :-)

I think the bob-tail engine is about US$6K.

TP

I

Wow! Really? That's a bargain.... nah...?

[Tommee]

Thank you all for your invaluable comments. I am certainly anxious about re-powering for many reasons as well as the astronomical cost. Seems like NZ$60k. They know how to charge in this Country!!!
I have owned her & lived on her for 33 yrs & do most maintenance myself where possible, hence I don't want anything Turbo or complicated. Being "old school" I certainly believe the old engines are the best & most reliable. I like simple. The BMW pushes her along at 6kts at 1800rpm & uses 3 liters per hr. It is quiet which many of these marinised engines aren't. Marinised Fords are popular here but still sound like a tractor coming into the marina!!

Why am I considering re-powering? This engine has now done close to 10,000 hrs. It is Aluminium & prone to corrosion which I try to stay on top of, but I see impending issues in some areas. It is smoking quite a bit, using/loosing oil & I suspect the valves are worn. Any parts are almost unavailable, I have found V12 in Vancouver & Navalis in Germany, both have some parts & seem to now be making parts. However this is all at high cost of product & even higher cost of shipping down here to NZ. Most engineers grumble about the engine, (they are uncommon here), shake their heads & don't want to work on it when I can't. Most advice is "stop throwing good money after bad". Nannis have been suggested, but the larger ones are Turbo charged. Kubotas have been suggested too. Yanmar seem very popular but usually in much lighter boats like Beneteaus. Maybe after listening to your comments I should re-think. If I could find a reliable engineer to put some work into it....I would never tackle the technical stuff myself...I would be overjoyed. However, they are like hens teeth around here. Will keep looking. Thank you all again.

[RaymondR]

My Kuboto V2203 cost about A$7,000 new and the transmission was A$2,500 about fifteen years ago. I marinisede and installed it myself. I specified the gearbox ratio to spin the prop faster consequently did not require a new shaft or prop. I probably could have done it for $5,000 using a Japanese auto diesel but decided on new after coming into an inheritance.

There are so many crooks in the marine service providers business I generally avoid them like the plague.