Converting a 97-ton steel ketch to electric propulsion

[GrowleyMonster]

So why do you want to go electric... to save money? Just askin.

[Steven UK]

I hope you can’t make this work, Not sure of the engineering’s involved and the financial aspect. But I hope you can make it work. May be planning and waiting whilst using a small diesel is a viable strategy... good luck.

[Capt. Ray]

The answer to your question, I hope, is on the below Page. If I missed anything feel free to message me. Basically we are going to have an empty, large engine room with two generators fully serviced, tons of room for batteries and a refit on a boat that is unique and is not intended for resale on the open market. We are a charity and cost is always a factor, but with well over 7,000nm with and without power I know what I need. Let's put it this way - when becalmed, even for extended periods, I only use power when absolutely necessary, otherwise will await wind. So it came down to a simple question "Replace the engine with another conventional diesel OR electric instead". I made the decision to go electric for many reasons and am not intimidated, I do have experience with dual-hybrid diesel-electric in the past.

DESIGN COMPETITION - converting 97-ton sailboat to electric propulsion - International Rescue Group

Originally Posted by GrowleyMonster

So why do you want to go electric... to save money? Just askin.

[Capt. Ray]

I know for sure I can meet my specifications having done the experiments to prove thrust for speeds required etc. No point in doing this project twice, I can wait until everything is in place. The choice is whether to put power down the shaft using conventional or electric motors, it can be done reliably either way and the ship already has redundant and reliable electric power generation. I chose electric for many reasons, one is that my Electronics Degree has a control systems leaning so I am not intimidated. Here is some interesting thinking re a DC motor option (scroll down to COMMENTS): TYPES OF MOTOR - International Rescue Group

Originally Posted by Steven UK

.........Not sure of the engineering’s involved and the financial aspect. But I hope you can make it work. May be planning and waiting whilst using a small diesel is a viable strategy... good luck.

[Capt. Ray]

To convert your "IFs" into actual facts:

Yes the existing engine has a terminal problem and must be replaced.

Yes International Rescue Group is an actual charity (did you see the website referred in the base post?). After 5 years of very hard operation this vessel needs a refit.

Simply replacing the existing engine is quoted at about $40,000 and not even needed as it was set up for a charter operation. We have a very different application. Going electric will probably cost less than a half of that sum, maybe even less.

With the existing configuration, experience and requirements I am confident we can replace propulsion cheaper with electric rather than simply replacing both the transmission and diesel engine. The question is in the details of the implementation, there are many options. Minimizing cost is important and we will only go back to a conventional engine/transmission replacement IF it proves to be cheaper. It won't.

Originally Posted by Uncle Bob

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?

[Singularity]

Originally Posted by 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.

You are saying that International Rescue Group endorses the procurement of a diesel-electric hybrid system to replace existing diesel ICE as the most cost-effective (and/or lowest carbon footprint) means of producing non-sail propulsion to IRG vessels to accomplish their medical and relief missions?

The primary organizational mission is medical and relief work, you have an ICE that works, yet the conversion makes financial sense. What is the non-fuel hourly cost of the already present diesel?

[rbrake]

Look to the European Work boat industry for hybrid drives. One comment from 50 years of sea experience. You will need the HP potential of the old engine. You don't have to use it but if facing a thirty foot sea and a full on gale you will want it. If you are staying coastal that's a different story.

[Capt. Ray]

No I am NOT saying that IRG endorses conversion of ICE to electric. Just in this one application it makes sense.

I don't think you read the web page brief. The existing engine and transmission are dead, defunct, kaput, uneconomical to repair, too old, inefficient, unreliable and expensive to maintain even when it did work. Pronouncements from multiple mechanics including a Volvo specialist. This is a repower job and a simple decision between a conventional replacement or electric. I chose electric for all the reasons in previous posts. Now it is a matter of design, sourcing and implementation. There are options.

Originally Posted by Singularity

You are saying that International Rescue Group endorses the procurement of a diesel-electric hybrid system to replace existing diesel ICE as the most cost-effective (and/or lowest carbon footprint) means of producing non-sail propulsion to IRG vessels to accomplish their medical and relief missions?

The primary organizational mission is medical and relief work, you have an ICE that works, yet the conversion makes financial sense. What is the non-fuel hourly cost of the already present diesel?

[SteveSadler]

This is an interesting challenge. I think the hydro electric idea is the most common practical system available. Given the minimal budget, just add the biggest dc motor you can afford or an ac motor if no batteries are used, and
Run with generators. Plans for the system are probably available on line. For carbon reduction, lots of batteries and charging systems are required but will pay for themselves with fuel and generator savings. A bow thruster may be needed to safely maneuver such a heavy vessel with so little hp. Or the tender can be your assist in port.
I see it as a test of seamanship more than a safety issue. Sailing vessels have been around a few thousand years longer than engines.

[jgbrown]

Originally Posted by Capt. Ray

I think you're referring to Azimuth thruster drives, an interesting idea becoming more popular with large commercial shipping though at an initial search very expensive, compared with a simple AC electric motor running off our generators... we are just a small charity with limited funds for this refit. In a small way, Torqueedos are electric azimuth pods!

We do not fit under commercial shipping rules so the regs we work to are frankly leisure boating.

I think you are on the right track with assessing YOUR horsepower needs. I would however compare like with like on the diesel vs electric. I have recently assessed this for myself and really, really, really wanted electric to win out. It didn't, even on initial system cost.




Never worked on the commercial tug ones, but I can tell you from dealing with the Searay/other rec boat ones ones that you NEVER want to deal with one if cost, reliability and serviceability are requirements. One boat that had them and was in charter was so bad for sucking up logs that they started lifting it after every single charter to check for damage. And the parts costs. How about 10k for a mounting plate full of tiny water passages that corrode through, plus only certain shops can even buy the damn things.





EDIT: Also to compare apples to apples, if all you need is 40HP to be happy, I would compare the costs of a Beta 43(last time I had one quoted it was just under 10k for me to pick up) to the cost and weight(and service requirements) of generators, additional batts, solar etc etc. Comparing a low HP electric setup to a 450HP diesel is apples to oranges. If you need decent HP and have that kind of space, I second the Cummins 5.9 dry exhaust setup and want to go used, cheap reliable and very serviceable, plus easy to install.

If you can design and install the electric system you can certainly do the diesel install yourself, especially going with something common like the beta. I would consider stepping up a couple sizes if budget allows, get prices on a few of the non-turbo Betas, pick the largest HP you can afford comfortably. You have the space and the simplicity and ruggedness of the design is well suited to what you are doing. Selling one or both of the gensets, not buying a lot of the other components and the price differential is significantly in favor of simple lower HP diesel, moderate solar, decent heavy duty inverter(I like Newmar for this, they are the naturally aspirated diesel of the inverter world) for house 110v needs.

[jgbrown]

Also if you go the small diesel route, look into https://loganclutch.com/marine-applications


You can EASILY generate enough power off the diesel as a generator without all the waste and wear of idling along for hours charging via small alternator with all the engine room space you have. This deletes the generators, and all their service requirements. You can sell them and offset the cost, or even simply pull the generator head off one to install. It is dead simple. You now have ONE fuel system to maintain, one engine to do oil changes on, etc. Buy filters etc in bulk, since you now only have one of each to worry about.
You will end up ahead on:

Weight
Simplicity of systems
Cost
Service time required.

[captlloyd]

Originally Posted by jgbrown

Also if you go the small diesel route, look into https://loganclutch.com/marine-applications


You can EASILY generate enough power off the diesel as a generator without all the waste and wear of idling along for hours charging via small alternator with all the engine room space you have. This deletes the generators, and all their service requirements. You can sell them and offset the cost, or even simply pull the generator head off one to install. It is dead simple. You now have ONE fuel system to maintain, one engine to do oil changes on, etc. Buy filters etc in bulk, since you now only have one of each to worry about.
You will end up ahead on:

Weight


Simplicity of systems
Cost
Service time required.

Nailed it !!

[Pete17C]

and behind on:

redundancy

[jgbrown]

Originally Posted by Pete17C

and behind on:

redundancy

Complexity yes, redundancy no. Single electric engine is also a single point failure, changing that was outside the design spec, the complexity of the power generation system means that without a ton of spares the odds of a problem causing a failure in the drivetrain are higher. In any case the owner has made it clear that the vessel is using it as auxiliary propulsion only, and does not require being able to use it often.

[Cadence]

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.

Trains and ferries. The diesel can run at a constant RPM, it likes, and the DC motors give finite control and as you pointed out instant torque.
I doubt on a limited budget it is a viable solution as apposed to just a small propulsion diesel.