DIY Diesel Electric Catamaran drives Feasibility ???

[a64pilot]

Originally Posted by skipmac

I confess my hands on experience with hydraulics is fairly limited, mainly farm tractors, log splitters and similar but so far all of those have been totally bullet proof for years and years.



I have read that hydraulic drive motors can be a bit noisy. Some say they make a whining noise that can be very annoying. Would love to hear comments about that.

Hydraulics can be noisy as Hell, but don’t have to be. Hydraulic power steering on automobiles for example, we have all heard one when the pump is going out, but normally it’s completely silent.

John Deere backhoes I’ve had I don’t remember hearing the hydraulics on them and you work the hydraulics constantly.
As strong and powerful as a back hoe is, the hydraulic pump is driven directly off of the front of the crankshaft and is about the size of a softball.
At least on my old JD410 anyway, don’t know about the new ones.

There are different types pumps and motors, I believe the piston motors can approach up to 98% efficiency, but don’t forget about pump efficiency and of course loss in the hoses from friction.

I’m not sure what all smaller equipment is hydraulic, where nearly all huge equipment is electric drive.
I’d guess that making hydraulics huge doesn’t work for some reason.

[Rapanui]

What is wrong with just replacing and improving the long tail drive? There are thousands of similar systems in use in Thailand and elsewhere. Electric or hydraulic drives will be expensive and require significant mods to the hull(s). I would keep it simple.
The alternative of the Sillette drive could be just as easy to fit provided you have a near vertical transom on the bridge deck which is big enough and strong enough to take the forces and moments exerted.

[akprb]

6000 to fix current set up?

Diesel and transmission good?

Fix it and go cruising.

I do not understand this fascination with electric.

[Pete17C]

Originally Posted by akprb

6000 to fix current set up?

Diesel and transmission good?

Fix it and go cruising.

I do not understand this fascination with electric.

You never need a tune up and the fuel doesn't stink.

[akprb]

Originally Posted by Pete17C

You never need a tune up and the fuel doesn't stink.

I get that and sure elec will be a viable option one day. Today just seems a lot of work and expense to not go very far.

We met some folks in New Zealand who literally won the lottery and built a beautiful cat with electric propulsion.

Their first trip up to Tonga was a nightmare with respect to the "engines" and they ended up heading back to NZ. We met them they were in the process of repowering with diesels.

I suppose if one is doing Wednesday night races and just needs to get from the dock to the starting line elec a great option, maybe one cruise a summer not too far afield.

For those going further afield seems like not a great option.

I love the smell of diesel as well

[warrior 90]

Originally Posted by Rapanui

What is wrong with just replacing and improving the long tail drive? There are thousands of similar systems in use in Thailand and elsewhere. Electric or hydraulic drives will be expensive and require significant mods to the hull(s). I would keep it simple.
The alternative of the Sillette drive could be just as easy to fit provided you have a near vertical transom on the bridge deck which is big enough and strong enough to take the forces and moments exerted.

I agree, why not improving the long tail drive. I like the simplicity of such a drive. Very few parts and they can be made or bought of the shelf in any place.
Looking at the photos only thing I would change is an electric/mechanic clutch between the drive shaft of the engine and the prop shaft. That would give me a cheap, easy and multiple use of the engine to drive an extra alternator, water maker etc

Sillette spares are expensive, have to be shipped from the UK, and there are quiete some issues if You don´t keep up with the maintenance. You can read all about the headaches on the Gemini forum.

I like electric and I like the natural cooling feature of pod drives and when they are mounted to the transom they are easy to take off. NO expensive haul outs etc..... AND NO seals in the hull to replace. They are also great for steering and have easy mechanics.
I would say a battery as a buffer is required. I would add on a bank of super capacitors to get a good management of the high loads. Also the components of the controller like clean voltage
But FIRST....How about the skills, tools and instruments... how easy $$$ will it be to fix it ?
Electric motors and controllers also don´t last forever.

[Scout 30]

New outboards are quiet, efficient & reliable. A friend's 40' Wharram has a Honda 40 on a pod that he winches up & down. I think 2 smaller outboards mounted on the inside of the hulls make more sense. You can sell the Beta for enough to buy the outboards.

[Pete17C]

Originally Posted by akprb

I get that and sure elec will be a viable option one day. Today just seems a lot of work and expense to not go very far.

We met some folks in New Zealand who literally won the lottery and built a beautiful cat with electric propulsion.

Their first trip up to Tonga was a nightmare with respect to the "engines" and they ended up heading back to NZ. We met them they were in the process of repowering with diesels.

I suppose if one is doing Wednesday night races and just needs to get from the dock to the starting line elec a great option, maybe one cruise a summer not too far afield.

For those going further afield seems like not a great option.

I love the smell of diesel as well

As it is right now, from reading the responses here, it seems like you can hang 2 of the high power trolling motors off the back of most modest size boats (OP has a cat) and get most places you need a motor to get. Keep two extras for redundancy, but add extra mounts and wiring and in a pinch you have 4. Still less cost than a diesel, with less maintenance, and better redundancy.


/why would a true sailor even need a motor?
//batteries are ballast
///more of a old school leaded guy myself

[Fore and Aft]

Lots of options to consider. I have done sea trials on a Pahi 40 that had two Yamaha 25hp outboards in pods under the wing deck. We managed to get 9.5 knots flat out.
I have also seen this system installed on a 40 foot cat. He had one Diesel engine in the cockpit and a prop in each hull. The owner was a huge fan of his system, but was not keen on the motor in the cockpit.
https://www.vetus.com/en/power-hydra...ropulsion.html
I can see my grandkids having electric motors once they sort out battery capacity and recharging abilities. Until then you have to love that sweet sound of an internal combustion engine.
Cheers

[s/v Jedi]

I think I could find everything I need for converting Jedi to electric drive here: https://www.electricmotorsport.com/marine

[jmh2002]

Originally Posted by Scout 30

New outboards are quiet, efficient & reliable. A friend's 40' Wharram has a Honda 40 on a pod that he winches up & down. I think 2 smaller outboards mounted on the inside of the hulls make more sense. You can sell the Beta for enough to buy the outboards.

Yeah I like the idea of electric propulsion but it's not quite there yet for small boats and it's still hella expensive to do properly.

So on a Wharram where the KISS principle applies I prefer the idea of two properly sized and properly installed outboards in retractable pods.

You still get twin engines for maneuvering, reasonable cost, light weight, retractable for low drag and drying out, and can even be winched off with a halyard and taken ashore for repairs if necessary, and a replacement (even a temporary ill fitting one) can be more easily dropped in place too.

On a Wharram portable fuel tanks are normally located amidships on deck in vented lockers, and petrol outboard fuel is available anywhere in the world.

I like all these positives for Wharram or similar simple cat.

One downside is not much charging from the outboards even though some models do have alternator output ability. But these days many simple boats want to rely on solar and wind charging anyway, plus a Honda genset as a backup. It runs on the same fuel as the outboards too.

[NahanniV]

The Sonic/Sillette drive is no longer available, even though the website shows it with pricing.

From: <sales@sillette.co.uk>
Subject: RE: Sonic Drive purchase inquiry

We are sorry to advise that we no longer manufacture any catamaran drive units and do not have any stock. Going forward, we are only providing a spare parts service.

Regards

Glen Print

Sales & Correspondence to:

Sillette-Sonic Ltd

9 Pilgrims Way

South Croydon

Surrey

CR2 7HT

[NahanniV]

Originally Posted by Rapanui

What is wrong with just replacing and improving the long tail drive? There are thousands of similar systems in use in Thailand and elsewhere. Electric or hydraulic drives will be expensive and require significant mods to the hull(s). I would keep it simple.
....

Improving the existing drive may be the simplest/cheapest path to take at this point.

The problems with the existing system are:

- noisy
- vibration at different RPM
- components are not that easy to source (14' * 1"Dia. SS shaft).

It seems like the noise and vibration may be mostly due to the thrust from the prop being transmitted thru the 14' prop shaft and the universal joint into a bearing that is not really meant to take that kind of thrust.

[valhalla360]

Originally Posted by Pete17C

You never need a tune up and the fuel doesn't stink.

1) Haven't done a tune up in decades.
2) The OP is asking about a hybrid system...it still requires fuel. A pure battery electric may not stink but it doesn't go very far on a charge.

[valhalla360]

Originally Posted by Rapanui

What is wrong with just replacing and improving the long tail drive? There are thousands of similar systems in use in Thailand and elsewhere. Electric or hydraulic drives will be expensive and require significant mods to the hull(s). I would keep it simple.
The alternative of the Sillette drive could be just as easy to fit provided you have a near vertical transom on the bridge deck which is big enough and strong enough to take the forces and moments exerted.

The long tails I saw in Thailand didn't include a U-joint. That seems like it could be introducing a lot of problems with reliability.

I'm not a fan of the stillette drive, I've heard enough hassles with them on other Gemini's. Much prefer an outboard option and it will likely be cheaper than any of the other options.