Converting a 97-ton steel ketch to electric propulsion

[GrowleyMonster]

I think a 50hp Kubota tractor diesel would be just the thing. Beta marinizes them and does an excellent job IMHO. Parts are from tractor dealerships, mostly, so no marine prices. Still want to go electric or hybrid anyway? Okay. Assuming the transmission on the diesel tolerates the shaft spinning with the transmission in neutral, you can simply piggyback a large electric motor over the prop shaft and couple with belt drive. You will want a VERY large bank for a vessel that size. And lots of solar, yeah. You would save fuel as long as you don't use the generator to charge the batteries. Solar and Regen charging would save fuel, maybe a lot of fuel. However, the initial cost would take quite some time to recoup. You would have a greener footprint, perhaps, but not save a tremendous amount of money.

[captlloyd]

Originally Posted by roverhi

a 75' boat and electric/diesel propulsion and little money don't go together. The conversion will cost a bundle and, without the proper design, be a very very poor replacement for straight diesel power. Think we have eco idiot thinking overwhelming the practical. Best solution, if this is a war on Carbon, is use the sails exclusively. If you have to get into a harbor with no wind, have a dinghy with a big enough motor to tow or push the boat in. As someone up the line said, you could maneuver in light wind conditions with a surprizingly small boat/outboard. Don't use the dinghy motor for getting around when anchored. Get the oars out.
O
Is the diesel busted beyond repair?? Will be way cheaper to replace the huge diesel with something a 1/4 that hp if you want to be truly eco responsible.
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Atolls solution makes as much sense as a diesel electric set up. Converting diesel fuel into elctrons to power an electric motor is not conservation
responsible. A smaller direct drive diesel will be more energy efficient. Yes, I know they power trains with hybrids but they do it for the instant torque of the electric motors and no gearbox.

X2. Think Cummins 5.9. A great engine that will run for ever, I bought a good used one for $2500, dry exhaust, keel cooled. A fraction of the cost of what you are talking about.

[billknny]

Wait a minute.... 97 tons... 78 feet.....

That seems out of whack, but MIGHT be right...

Are you quoting displacement (which is the number needed) or is that the "Gross tonnage" on the documentation certificate, which is something else completely....

[StuM]

Originally Posted by billknny

Wait a minute.... 97 tons... 78 feet.....

That seems out of whack, but MIGHT be right...

Are you quoting displacement (which is the number needed) or is that the "Gross tonnage" on the documentation certificate, which is something else completely....

2013 survey says:

87ft LOA, 71.36 LOD, 65'7.5" LWL
Grs Tons: 77 Net Tons: 69


No mention of displacement anywhere that I could find.

[Mike Banks]

Personally I would just replace the Volvo or give it a service. It does not sound to be too overpowered to me. Have you ever had the vessel loaded to its Plimsol mark for salt water? I suspect it seems overpowered because the vessel is only lightly loaded.

[Uncle Bob]

Originally Posted by Mike Banks

Personally I would just replace the Volvo or give it a service. It does not sound to be too overpowered to me. Have you ever had the vessel loaded to its Plimsol mark for salt water? I suspect it seems overpowered because the vessel is only lightly loaded.

Pretty much my thoughts as well, also a somewhat larger engine run at less than full throttle will be more fuel efficient and less demanding of expensive repairs,
Another query I have is if this organisation is a charity or at least of charitable intent why are they looking to spend what will be many more thousands of charitable dollars on something that really does nothing towards their claimed outcome. Even if the existing engine has a terminal problem it will prove far cheaper to replace like with like.
Or am I just being cynical?

[Capt. Ray]

Your story describes a boat with inadequate ground tackle - we have two FX125 Fortress anchors (the largest they make) and a 350 pound ship anchor. The Fortresses do most of the work. The incident you are describing is not one that ever happened when I was around but she was certainly in the Bahamas a lot before my time.

Originally Posted by billknny

We have "run into" this boat before....

And one more thing...

[Capt. Ray]

To clarify - are you advocating a DC motor driven from a large battery bank? Understood a genset can charge the batteries that drive the motor. Or even both gensets for that matter in a redundant system.

Why would that be better than directly driving an AC motor from a genset (apart from short periods of quiet battery propulsion)?

Ground tackle is already two FX125 Fortress (huge anchors) and a 350lb main bower. We are replacing all chain and gypsies on our very reliable electric 24v windlass. I would also like a very large traditional yachtsman (kedge) anchor on a cathead.

Originally Posted by hpeer

Ray,

I’m a bit confused. You have a 20kw (26hp) diesel generator and a 16kw (23hp) generator and you need a fairly large generator for water making. And you are near broke.

It sounds simple to me, install a large battery bank and a 40ish HP drive motor. The gens can charge the batteries and the batteries drive the motor.

Keeping it simple either gen drives the charger to charge the batteries and batteries drive the motor. You then run up to 26hp to the shaft so depleting batteries. If you run over 26 hp you deplete batteries. Bigger the bank longer you can run at high HP. Presumably you only need high HP for short duration anyway.

When you get more cash you can install more batteries and/or add more solar. Maybe upgrade you ground tackle?

I think you pretty much have the info you need.

[hpeer]

Now Ray, I met you in the Bahamas after your ground tackle broke and she went up on some iron shore island outside Spanish Wells. As I recall the engine was inoperative then, someone had hydrolocked her, and you sailed/towed her down to Georgetown.

I think there are folks here who are trying to give you good advice and who have your best interests at heart. I suspect that said advice is probably not what you would like it to be in your heart of hearts. It’s a bitter truth.

I don’t know your cash situation but maybe the boat is a bit more than the mission can sustain. She surely needs a haul and some hull repair besides the engine work.

Did you ever get her hauled in Fort Lauderdale?

[Capt. Ray]

The present engine (450HP) is drastically overpowered. Apart from experimenting with full power occasionally and to blow the turbos for a while, I never motored at more than 1200RPM and that pushed us plenty fast.

I have 1,580 gallon fuel tanks and have gone from almost empty to full, over 5 tons. That makes a waterline difference assuredly, I have filled to the brim from completely empty once, it is quite a sight to see. The 500 gallon water tank being filled at the same time made it a dramatic "top-up". I have also carried over 12 tons of relief cargo and that put our bootstripe from 12" above the sea water to 16" below!

A previous owner believed in POWER and used her exclusively as a motorsailor, I have had a crewman from 25 years ago aboard and he recognized none of the machinery! In his time it was a simple naturally aspirated diesel and a single genset. Right now she sits horribly out of trim stern down and bow up and I'll be glad to take a lot of weight out of the engine room, her trim has destroyed her sailing characteristics, after well over 7,000nm I think I'm getting a good idea what she needs.

Originally Posted by Mike Banks

Personally I would just replace the Volvo or give it a service. It does not sound to be too overpowered to me. Have you ever had the vessel loaded to its Plimsol mark for salt water? I suspect it seems overpowered because the vessel is only lightly loaded.

[Capt. Ray]

The previous engineer before we acquired the vessel reported 97 tons on the travelift gauge (they are notoriously inaccurate). Definitely overweight from her original design after a LOT of heavy gear has been installed. I plan to simplify and reduce. Probably full tanks. When I haul next she will be pretty dry. This is a VERY heavily built traditional Dutch steel ketch. I am surprised at how easily she is driven in light airs having motored, motor-sailed and sailed her for well over 7,000nm. Yes gross tons are what was admeasured on a Panama Canal passage but displacement is something that we don't fully yet believe from previous reports or documents.

Originally Posted by billknny

Wait a minute.... 97 tons... 78 feet.....

That seems out of whack, but MIGHT be right...

Are you quoting displacement (which is the number needed) or is that the "Gross tonnage" on the documentation certificate, which is something else completely....

[hpeer]

Ray,

I was more thinking along the lines of a large UPS where mains power (from gen sets) charges the battery bank. The battery bank then drives a large inverter to reproduce AC.

I think you could do it either way, which is technically the best and most affordable need to be worked out in the details. To a large extent your solution is going to be driven by availability and cost. Compromises will be made.

[Capt. Ray]

The decision is made, I am not installing a traditional diesel engine again. I will take out the entire existing engine and transmission, it is too old and too expensive to repair and maintain, also with all the Volvo fly-by-wire too complicated and unreliable.

I expect to use fuel but certainly not as much as the old engine consumed. A solar power/genset charging/large battery bank/DC motor solution is possible, but so is a genset-to-AC motor approach which is probably more practical and a lot cheaper. It comes down to budget and other trade-offs.

Originally Posted by GrowleyMonster

I think a 50hp Kubota tractor diesel would be just the thing. Beta marinizes them and does an excellent job IMHO. Parts are from tractor dealerships, mostly, so no marine prices. Still want to go electric or hybrid anyway? Okay. Assuming the transmission on the diesel tolerates the shaft spinning with the transmission in neutral, you can simply piggyback a large electric motor over the prop shaft and couple with belt drive. You will want a VERY large bank for a vessel that size. And lots of solar, yeah. You would save fuel as long as you don't use the generator to charge the batteries. Solar and Regen charging would save fuel, maybe a lot of fuel. However, the initial cost would take quite some time to recoup. You would have a greener footprint, perhaps, but not save a tremendous amount of money.

[Capt. Ray]

I do not think I am an "eco idiot" but in fact have thousands of sea miles on this vessel the last 2,500nm being under pure sail. In those last 2,500nm the only speed I have required under propulsion has been 3.5 to 4 knots in light air as is written in this brief. I have hip-towed with a 20HP outboard when needed - and it worked for maneuvering into port) and experimented with other configurations. Under tow, a 50HP outboard does a very good job that I am more than happy with.

Yes you are quite right, I could definitely tow but long distances and in heavy swells using an outboard or a dinghy is a real pain. I don't have a drum to beat time nor do I carry slaves so I think sweeps are out of the question. So having a more permanent drive on the main propeller is simply practical and I believe that can be achieved reliably reasonably well with one or two electric motors off the generator/s.

Originally Posted by roverhi

a 75' boat and electric/diesel propulsion and little money don't go together. The conversion will cost a bundle and, without the proper design, be a very very poor replacement for straight diesel power. Think we have eco idiot thinking overwhelming the practical. Best solution, if this is a war on Carbon, is use the sails exclusively. If you have to get into a harbor with no wind, have a dinghy with a big enough motor to tow or push the boat in. As someone up the line said, you could maneuver in light wind conditions with a surprizingly small boat/outboard. Don't use the dinghy motor for getting around when anchored. Get the oars out.

Is the diesel busted beyond repair?? Will be way cheaper to replace the huge diesel with something a 1/4 that hp if you want to be truly eco responsible.

Atolls solution makes as much sense as a diesel electric set up. Converting diesel fuel into elctrons to power an electric motor is not conservation responsible. A smaller direct drive diesel will be more energy efficient. Yes, I know they power trains with hybrids but they do it for the instant torque of the electric motors and no gearbox.

[Capt. Ray]

That is true, in Spanish Wells we had a 72-knot storm blow through (forecast at 40kt) and our main anchor chain broke to the Fortress anchor which didn't move (recovered). That was butt-clenching and I am amongst the few who know what it sounds like when a chain parts in a howling wind. Unfortunately the other two 350lb ship anchors I set dragged. BTW in that very same blow a 50-foot new Beneteau told me that they were motoring at full power into the wind and still dragging... fortunately after a few hours they finally stuck.

The story you posted about dragging in Georgetown may have happened when I had subcontracted the vessel to a company that intended to take her for a major refit in Florida (I was in Haiti at that time on another boat) but they eventually backed out so I repossessed and since then sailed her engineless through the Bahamas to Florida, Cuba and into the Gulf, I am now in Mexico and we have a Yard in Guatemala ready for us, set up with a large travelift to haul and block for a long re-fit project. It has been quite a learning experience to sail a boat this size for thousands of miles and now have a serious appreciation for the men of iron who sailed ships of oak.

As for the forum advice - fundamentally this is all about how to put power into a propeller shaft, the two obvious options are a replacement conventional engine or electric motor. In this boat there are options especially considering I have two Northern Lights generators. Electric motors can be as reliable as diesel engines. I have the possibility of installing two electric motors. There are trade-offs either way. Most solutions will be more fuel-economical than the existing old engine that must be extracted whatever happens.

Originally Posted by hpeer

Now Ray, I met you in the Bahamas after your ground tackle broke and she went up on some iron shore island outside Spanish Wells. As I recall the engine was inoperative then, someone had hydrolocked her, and you sailed/towed her down to Georgetown.

I think there are folks here who are trying to give you good advice and who have your best interests at heart. I suspect that said advice is probably not what you would like it to be in your heart of hearts. It’s a bitter truth.

I don’t know your cash situation but maybe the boat is a bit more than the mission can sustain. She surely needs a haul and some hull repair besides the engine work.

Did you ever get her hauled in Fort Lauderdale?