A repower for Arianna?

[Ron M.]

As far as omitting the v-drive, I think anyone who has repowered a cd30 has given this serious consideration. My recollection is the engine would have to be relocated almost a foot forward,(maybe more) and lower to get the shaft to line up with the existing shaftlog. The entire engine bed would have to re-engineered along with the companionway steps and perhaps part of the galley. Given that choice I stayed with the v-drive. The Hurth ZF is much quieter than the old Walker,(Walter ?).
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Chevrolet beretta specifications

[username]

I'm obsessing on an electric re-power for Amiable my CD-30C...

I'm drawing down on next winter...the old Volvo has it's charms, but I am really into the idea of no oil, no smoke...for a sailing craft all I see are up sides...

Has anybody else gone this way?

[Ben Thomas]

Although not set up for our pesky v-drives. Beta is now offering a hybrid system in the United States. Beta and Hybrid marine UK have worked for several years on R&D
Check them out here:
http://betamarinenc.com/Hybrid.html

Also lots of information here:
http://www.hybrid-marine.co.uk

Ben

[Klem]

While I have not installed an electric drive in a boat, I have built 3 electric cars and 2 hybrids which use similar components but a very different duty cycle. My personal opinion on putting an electric drive system in a boat is that you need to take a very careful look at how you use the powerplant before you think about converting. It is the right thing for some, but completely wrong for others.

How do you use the boat (daysails, extended cruises, world voyaging, etc)? What speed are you planning to motor at? What role does the motor play? Do you use it for maneuvering in a marina only or do you use it to power the boat on windless days or do you prefer to power upwind than sail or even do you see it as a safety device in severe weather? Out of these questions, you should be able to develop an approximation of the most severe requirements which is what you will need to develop your system around. These requirements need to be a power and amount of time. Also, how will you recharge the system, do you have shore power or are you on a mooring?

Electric drives are really a system so they need to be specified together. The voltage rating of all the components needs to be equal which can be tough with batteries and motors. As a general rule, higher voltage is better from an efficiency standpoint but worse from a safety standpoint and number of batteries. Also, you need to choose AC or DC. A lot of AC motors are sealed which makes them better in a corrosive environment, having a flatter torque curve and are better for regeneration. DC motors tend to be a lot cheaper, have a torque curve which goes to 0 at high rpm and often don't do regen very well if you are interested in that.

A good starting point is motor selection. If you only use the motor to push the boat along in calm conditions, then 5kw might be appropriate but if you like to push into a headwind, 10kw is probably more appropriate. This is a personal choice but you can never decide that you need a bigger motor when the conditions get rough. Something to be careful of is that most motors spin in the 4-5k rpm range and you shaft will spin about 1/4 of that speed requiring you to have a gear reduction (this is the reason that a lot of boats are belt drive which requires some extra bearings).

Selecting a controller is also important and there are several decent choices. In an AC system, the controller will often be sold with the motor because they need to be more closely matched but with a DC system you can typically choose.

Choosing a battery bank is where this usually gets scary from a weight and space standpoint. You need to take the worst case power and time scenario from above and then size a battery bank from that. I would guess that even the most conservative of us motor around using 4kw for a CD 30 in calm conditions. If you want to go 10 hours between plugging into shore power which isn't much, this would be 40 KWhrs. If you want to push into a headwind for 10 hours, it will probably be more like 80 KWhrs. Also important in battery selection is the motor and controller efficiency (~90% each) and you should never allow the batteries to go below 80% discharge. Keep in mind that over time, your batteries will loose capacity also. So our 40KWhrs of useful energy now requires 62 KWhrs of battery storage. For comparison, a Trojan T105 battery (62lbs each) has a capacity of 10.6 KWhrs so you would need 6 batteries. If you want a range comparable to the diesel that the boat comes with, you would need something like 20 batteries which would be totally impractical. There are fancier battery technologies out there but they are very expensive and less forgiving to overcharging/overdischarging.

Charging is another important consideration and again there are several good units available. You should be able to charge off of a 110V 30A circuit at a minimum and it is nice to have more options. Charging time is not insignificant, at 110V, 20A, you are only charging at 2.2KW excluding charger and battery efficiency. Personally, I like to get a more powerful charger than this but they are more expensive and you need a place to plug it in.

There are lots of other considerations like safety devices, proper wire size, etc. None of them will stop you from doing a project but if you are serious, you need to plan ahead on all of them.

Many people suggest that they will solve the range problem by creating a hybrid. They plan to generate electricity either through a generator, solar panels or a wind generator. A wind generator will only help when you are not under power, if you are going upwind you will be worse off and if you have a beam wind you would get much more benefit from sailing. Solar panels are a drop in the bucket compared to your power consumption, most panels are ~100W so you would need on the order of 40 combined with good sun and no shading to keep up with power demand. Generators are actually capable of producing some real power but often are inadequate. Take a 2kw unit, it can probably only produce ~1/3 of the power that you will be using. This also assumes that you have a charger capable of keeping up or have a DC generator. While this won't keep up, it will extend your range. If you throttle back, you might be able to double your range with a 2kw generator. You could use a bigger generator like a 4kw unit but that would defeat the purpose of the electric drive in most cases. Series hybrids are inefficient in a sailboat because of all of the energy conversions and the constant duty requirements. Everytime you convert forms of energy, your efficiency drops and parallel hybrids have to convert forms a lot.

There are some real benefits from having an electric drive. The coolest part is how quite they are, they are not silent but they are much more pleasant. They also have very few moving parts but they do have some corrosion prone electronics.

All of the numbers in this post are open to interpretation but they should give a pretty good start. The basic electrical equations will be true so you can solve them for any inputs you want. The biggest benefit would be to slow down a lot and use less power but I doubt that many people would be willing to slow down enough.

I hope that this helps.

[Bruce Dart]

A lot of folks have cursed the engine access problems with the CD-30's v-drive. I'm not familiar enough with the engine layout in the 30 (the CD-25 we used to have had an outboard) but a solution Bud Taplin, who used to be the plant manager at the Westsail factory, came up with was to install a low profile hatch in the cockpit sole. Although not absolutely necessary, a cockpit grating to cover it is a nice addition (the underside of the grating needs some tweaking to fit right.) You need a good quality hatch so it seals properly. The hatch also needs to be located where you can reach in from the inside to undog it. But once it's in it gives great access to the back of the engine.

Has anyone tried this on a CD?

[Tod Mills]

That is LaVida (CD 33), with Mike R doing the very realistic modelling. You will notice he even dug out a few tools to scatter around the cockpit, just for the pic! . It is a commercial one (you could literally drive a truck over it).

[Bruce Dart]

That looks like an even better solution than a conventional hatch since I'm guessing it has latches on the top rather than the bottom. Seems like a relatively simple fix.