Electric motors on a Woods Flica 34' sailing catamaran

[sailor4life7777]

Thanks everyone for all the fantastic feedback!

Let's say, theoretically, I equipped the flica with an electric inboard in one hull, and a comparable diesel inboard (with alternator) in the other hull and I balanced the weight between the two hulls. I plan to carry enough diesel fuel to get me out of any sticky situation I might encounter on a long voyage. I feel like a lot of the potentially dangerous scenarios could be overcome with good seamanship, planning, and good sailing knowledge.

The best way to be safe is to strive for excellent seamanship. Which means being in the right ocean at the right time, reading weather forecasts, ability to heave-to and sailing knowledge in general, good route planning, and so much more.

Even with the best of seamanship, eventually you will encounter heavy weather. In which case, I would heave to. If I really need power, and the battery bank is depleted, I could use the diesel to motor.

Now given the scenario stated earlier, (close to shore, weather changing, currents, and wind unfavorable). I would first try to avoid that situation, but the diesel would come in useful at that point as well.

Are there any other scenarios you guys can think of that would be potentially dangerous in a flica equipped with one inboard electric and one inboard diesel/alternator?

The diesel/alternator could also charge the lithium batteries during long stretches of cloudy days. And I wouldn't need a generator, so one less motor to maintain.

I also plan to put in a watermaker, most likely the seawater pro. I spoke with them and they said that they will soon be selling a 12V brushless high pressure pump motor within a few weeks, I think I will probably go with that.

I spoke to Elco motors directly and they said that all their inboards have regen. However, I couldn't find anything on the website about regen, which is surprising. I feel like if they really had regen, they would definitely put it on the website, so maybe the person I spoke to was a trainee or just didn't know. If you guys think this is fishy, I will definitely call again to confirm if they really have regen.

I'm thinking of steering with a monitor windvane as autopilot isntead of installing an electronic autopilot.


I want to be able to circumnavigate with this so I want to make sure I can handle any situation that might come my way. During the long stretches like the Pacific crossing, I do not plan to use the instant pot/air fryer, fridge/feezer, aircon, or anything really other than the essentials to save my power for the engines. I won't use the diesel engine at all except for emergencies, and will only use the electric engine if there's no wind but plenty of sunshine. I probably won't install aircon, but will probably install a small fridge/freezer, but won't use it during ocean crossings.

[sailor4life7777]

Thanks for the reply! It would be 24V batteries and I will wire them to get 48V for the electric motor. Yes I will try to match the thrust from the two props, thanks for the tip!

Originally Posted by fxykty

Is that 400Ah at 12V? If so, that’s not very much if you want electric cooking, let alone to power a motor (and aren’t electric motors powered by 48V?). We are trialing an electric air fryer rated at 1800W and when it’s heating up it is pulling 160A through our inverter. On another site I’ve seen figures of 160-200 Ah per day (at 12V) for electric cooking alone.

Regarding different motors, as another poster mentioned, that you get very similar thrust from the two props despite on electric and one diesel. Otherwise, motoring will be a real pain with the boat always driving to one side.

[tkeithlu]

And good morning, Sailor Forever.

Wow! You're getting lots of thoughtful responses. Plenty to think about. In response to your follow-up questions, first, I continue to be concerned about asymetric thrust on one engine and one motor, but that's been said. The question of regeneration: Any regeneration from a prop to the motor comes in the form of drag, and at fairly low efficiency. In other words, you will slow down your boat while sailing more than you will propel it with the electricity produced by that drag.

You could go with two electric motors plus one genset big enough to run both motors without battery accumulation. Otherwise, it's a centerline thrust single engine, which means a gasoline outboard. You lose the ability to pivot on two props when you do that.

[Sos]

I am no expert with electric drive but I would not feel safe with the amount of drive time you are looking at. I think at least a diesel engine would be very sensible and would make your life a lot less stressful! In bad conditions it is amazing what a difference a diesel ticking over, while going to windward, makes. Plenty of other reasons as already mentioned.



As a Flica owner (with twin diesels that I am very glad about) why not build the extended 37' version?

[nwdiver]

A pair of Beta Marine Hybrids at 14hp each, diesel when you need it electric when you can, also either one will push out 3500watts or so as a generator......

[sailor4life7777]

Originally Posted by nwdiver

A pair of Beta Marine Hybrids at 14hp each, diesel when you need it electric when you can, also either one will push out 3500watts or so as a generator......

Thanks for the suggestion and looks very interesting! But wouldn't I be able to get the same benefit of this hybrid engine with one electric motor and one diesel motor with comparable thrust? Are there any advantages to the 2 beta engines over the diesel/electric setup?

Thanks everyone for all the thoughtful tips and advice!!!

[Craig Cape Town]

HI sailor4life.
Another alternative is to use outboards. Here they are on a small cat in Cape Town.

[Craig Cape Town]

Hey sailor4life. How far along are you on the build?

I built a Woods Flicka a few years back. It was a lot of work and a project not for the faint hearted, but a great experience in which I learned a lot and gained new skills.
A book I found to be the bible of wood/epoxy boatbuilding is the Gougeon brothers on boat construction. It has many useful tips and techniques.

We'd be interested to see the process unfold if you don't mind sharing as you go along.

[double u]

solution I'd go for: ~10hp outboards in wells (see profile for my cat xperience)

[Bunji]

Currently have 2 x 9.9 hp high thrust Yamahas that push me along at 10 knots (4 to 5 litres per hour) very simple and economical, I to like many others would hope to one day convert to electric but the cost of doing so simply makes it prohibitive, realistically you would need a much bigger system than the one mentioned, a rooftop (hardtop) covered in lightweight panels 2000 watts + and a 1000 amp/hr lithium battery bank, with a battery management system solar controllers etc, 2 x 10 hp electric outboard motors all up very expensive

[double u]

in view of the size of the boat & yoursailing plans (& my own past mistakes) let me emphasize: try to be as light as humanly possible, LIGHT!!! Don't waste brain- & other power on "solutions" that might be feasible 20 years from now, but not now. Put all the money saved into things that enhance the sailing performance of the boat: good sails, lightwind sails, sailhandling equipment, stuff that minimizes upkeep & maintenance of the boat. Maybe you will only ever sail once to Tahiti: you don't want to have to waste your time there repairing stuff. Keep it simple!

[sailor4life7777]

Originally Posted by Craig Cape Town

Hey sailor4life. How far along are you on the build?

I built a Woods Flicka a few years back. It was a lot of work and a project not for the faint hearted, but a great experience in which I learned a lot and gained new skills.
A book I found to be the bible of wood/epoxy boatbuilding is the Gougeon brothers on boat construction. It has many useful tips and techniques.

We'd be interested to see the process unfold if you don't mind sharing as you go along.

Hey Craig glad to meet a fellow Flica builder! I pmed you, but I'm still working on the bulkheads so I got a ways to go still! I will definitely keep you updated. And yes that gougeon book is amazing!

[sailor4life7777]

Thanks for the reply and your point about weight is well taken! And yes I plan to invest in good sails and good sailing equipment as sailing would be my preferred means of travel.

Originally Posted by double u

in view of the size of the boat & yoursailing plans (& my own past mistakes) let me emphasize: try to be as light as humanly possible, LIGHT!!! Don't waste brain- & other power on "solutions" that might be feasible 20 years from now, but not now. Put all the money saved into things that enhance the sailing performance of the boat: good sails, lightwind sails, sailhandling equipment, stuff that minimizes upkeep & maintenance of the boat. Maybe you will only ever sail once to Tahiti: you don't want to have to waste your time there repairing stuff. Keep it simple!

[Craig Cape Town]

Hi S4L. I couldn't figure how to paste pics in pm so I'll just reply here. Please excuse thread drift. I did the wood/epoxy build, as my dad had a woodwork joinery and that's the medium which I had most experience with at the time. Which method are you using?
If I were to build another cat, I'd look for a hurricane damaged hull for reconstruction or use the Derek Kelsall foam core method. Foam core results in a lighter build and glass has greater appeal when it comes time to sell. Wood takes a lot of time (construction, fairing, sheathing and painting).
I was lucky to have other boat builders around who gave me good advice. One in particular, who had just completed a 45 ft Simonis Cat (designer of the Leopard cat), convinced me to make some changes to the origional Woods plan. This is often where home builds go wrong, but having seen the Simonis boat, I thought it was a good idea.

I did not like the flat deck surfaces nor the hard chine of the gunnel on the woods cat, so we added curved tops to the bulkheads to reshape the deck and used strip plank to shape the gunnel before glassing over and under it.


I continued the stringers about another foot aft of the last little bulkhead to give room for transom steps. On the Woods design there's just a flat panel on the stern.

I made the stringers each in one continuous length instead of scarfing them on bit by bit. This made "the rib" cage curve evenly and gave the hull a natural continuous bend. We found that the stringers needed to be forced down onto the stem and the natural curve wanted the stem to be a little further forward. So we made the bow a foot longer by moving the stem forward.

This also made the trampoline area bigger. It's really small on the Woods plan. One other reason for doing this is that the woods bridge deck seemed too far forward and at greater risk of bridged deck slamming.
Plywood boxed channels were added underneath and glassed over as bridge deck stiffeners.

Here you can see the top of the bulkheads are curved to shape the deck. The extra foot in length makes the fore peak bunk space more useful.

You'll likely get a lot of nay sayers, thinking that you are crazy to build a boat, when there are so many good used boats available. They do have a valid argument. I took quite a knock when I sold as these boats don't have the same perceived value as production boats. If I had worked the same number of hours at a job instead of on the boat, I probably could have bought a used boat with the money earned. The costs add up and if you're doing a home build you need to crunch the numbers and watch you spending. My biggest mistake was renting a warehouse for construction. If you can find a barn or free space, then grab it as the build will usually take longer than you expect. I started by buying cloth and epoxy as I needed, which was quite expensive. Later I bought a 44gal drum of epoxy and full rolls (400ft) of cloth at wholesale prices (half of retail).
Feel free to bounce ideas off of me. Good luck.

[double u]

Originally Posted by Craig Cape Town

Hi S4L. I couldn't figure how to paste pics in pm so I'll just reply here. Please excuse thread drift. I did the wood/epoxy build, as my dad had a woodwork joinery and that's the medium which I had most experience with at the time. Which method are you using?
If I were to build another cat, I'd look for a hurricane damaged hull for reconstruction or use the Derek Kelsall foam core method. Foam core results in a lighter build and glass has greater appeal when it comes time to sell. Wood takes a lot of time (construction, fairing, sheathing and painting).
I was lucky to have other boat builders around who gave me good advice. One in particular, who had just completed a 45 ft Simonis Cat (designer of the Leopard cat), convinced me to make some changes to the origional Woods plan. This is often where home builds go wrong, but having seen the Simonis boat, I thought it was a good idea.
Attachment 228386
I did not like the flat deck surfaces nor the hard chine of the gunnel on the woods cat, so we added curved tops to the bulkheads to reshape the deck and used strip plank to shape the gunnel before glassing over and under it.

Attachment 228387
I continued the stringers about another foot aft of the last little bulkhead to give room for transom steps. On the Woods design there's just a flat panel on the stern.
Attachment 228384
I made the stringers each in one continuous length instead of scarfing them on bit by bit. This made "the rib" cage curve evenly and gave the hull a natural continuous bend. We found that the stringers needed to be forced down onto the stem and the natural curve wanted the stem to be a little further forward. So we made the bow a foot longer by moving the stem forward.
Attachment 228388
This also made the trampoline area bigger. It's really small on the Woods plan. One other reason for doing this is that the woods bridge deck seemed too far forward and at greater risk of bridged deck slamming.
Plywood boxed channels were added underneath and glassed over as bridge deck stiffeners.
Attachment 228385
Here you can see the top of the bulkheads are curved to shape the deck. The extra foot in length makes the fore peak bunk space more useful.

You'll likely get a lot of nay sayers, thinking that you are crazy to build a boat, when there are so many good used boats available. They do have a valid argument. I took quite a knock when I sold as these boats don't have the same perceived value as production boats. If I had worked the same number of hours at a job instead of on the boat, I probably could have bought a used boat with the money earned. The costs add up and if you're doing a home build you need to crunch the numbers and watch you spending. My biggest mistake was renting a warehouse for construction. If you can find a barn or free space, then grab it as the build will usually take longer than you expect. I started by buying cloth and epoxy as I needed, which was quite expensive. Later I bought a 44gal drum of epoxy and full rolls (400ft) of cloth at wholesale prices (half of retail).
Feel free to bounce ideas off of me. Good luck.

Absolutely correct: the "sensible" thing to do is to buy secondhand - but once in a while "unsensible" shows one, what life is all about. "Not sensible" to build the boat oneself, but what an experience! Very few moment equal the landfall after your first oceancrossing in a boat that one built oneself. (Nearly 40 years ago - but thinking back still moves me)