Outboard lower leg as a pod drive

Currently have this diesel-hydraulic setup. I was thinking of removing the diesel and installing electric motor, driving a pod drive... and was wondering why I couldn't drive an outboard lower leg - I think there is a thread here, but I'm struggling to find the thread

 

Crofton!
How close to the mill are you?

No reason why you couldn't do it.
Or mount the motor and prop right in the rudder.
Called a live rudder.
Or do like Duffy in California and mount the motor vertically inside the hull and gear it down to the prop shaft in the rudder.
I'll look for a link. (EDIT: Look Below)
The dockside handling characteristics of this are impressive.

What a crappy set up you have now.
Did you do that?

Cheers, BB.

Power Rudder is Unique to Duffy Boats https://www.boatdesign.net/threads/power-rudder-is-unique-to-duffy-boats.60535/

 

"Did I do that?' Cheeky bugger... no. I didn't, but thanks for the thought.

Re: Crofton.... I overlook the ferry terminal... so very close to the mill. This boat was 'abandoned' on our mooring buoy out in Osborne Bay, we figured we'd buy the buoy off the in-laws in case we buy a boat... seems we 'caught' one. Now I have a project.

I didn't expect the hybrid hydraulic system. The vertical mount was something I had considered... though not in the rudder, but that would make for very responsive motoring. I'd really appreciate those links mate. Cheers JJ

 

You would need to carefully do your sums as regards input shaft RPM and power output, and gearcase ratio and prop pitch.

 

What do you want exactly, a pod drive, meaning a full 360° steerable driveleg, or simply a fixed leg? The first is expensive, the other is commonly called a saildrive, and I bet you can find a second hand one, most new production boats use them. There is no need to muck around trying to adapt an outboard leg.
If your only desire is to switch to electric, the simplest way is to mount the electric motor where the hydraulic prop drive now resides. If space inside the keel is an issue, that can be resolved with two pulleys and a chain or belt.
May I ask why you want to change the current setup? Is something broken and unrepairable?

 

The original setup is a disaster!
Ideal setup for hydraulic drive would be to mount the hyd motor directly on the rudder, and second best might be to cut an propeller aperture in the skeg Just ahead of the rudder.
No need to re-invent the Sail Drive, as Rumars mentions, unless your resources and patience are large. (LARGE!)

 

The propeller on the rudder would make the boat steer poorly under sail.

 

I edited my post above to include a link.
Just Google: Duffy Boats California live rudder
and see what you get.

 

They have the combined complications of a sterndrive and a rudder. The existing setup would be very easy to convert to electric. However, it is difficult to understand why. Diesel/electric will still need the engine to generate electricity.

 

Gonzo: See above, the diesel is due to come out in his scenario.

 

Where is the electricity coming from?

 

I've considered a Thunderstruck electric system with a motoenergy ME1115 motor. That's what I thought I was going to do... until I found out it didn't have a typical engine/gearbox/prop shaft set up.
While I am considering the saildrive... I could also - possibly - drive the current, or existing shaft, via pulley with the motor in a "dry pod" in the bilge (Cardboard is the diameter of motor and the length including a pulley). The pics are terrible as I am still cleaning out sludge a crap deposited over 15 years...
The water accumulating here has been due to open and leaky hatches, as for the 9 months it was on our buoy (where it was 'abandoned), through the dry summer months, it did not take on any "sea" water. I'm really just playing with options now as I have, on the one hand, a lot of flexibility, and on the other... I am limited - perhaps by what I am willing to take on... though I think I'm fair game to give a go at anything. The boat came to us for free... and I know there is no such thing as a 'free' boat... so I figure I can spend a wee bit on her. I've also become emotionally attached to this bloody thing, and not to mention a bit determined, as sooooo many people have told me what I can't to, or shouldn't do. It's my time to waste, is what I figure... and at at this point, I really haven't dropped much capital into the boat. We'll see where it takes me. But there's decent constructive advice here, and I welcome all of it. Cheers

 

Well, you sure have a lot of cleaning to do. Buy some TSP and a pressure washer.
You might get lucky and the diesel hydraulic system still works, or can be made to work for a small amount of money.

Your boat looks to me like a IOR design that somebody added the big skeg and homemade rudder to tame it downwind. That's probably the reason for the hydraulic drive, the prop space was taken by the skeg, and they did not have saildrives back then.

I am looking forward to the rebuild thread.

 

Installing anything at the bottom of the bilge will create maintenance problems. That propeller is quite low, and could be installed higher, which would give easier access. Hydraulic motors are cheap and readily available. If you install an electric motor, the options are a huge battery bank or a continuously running generator. The first option means that you have to install solar panels and wind generators. Also, the battery bank is going to occupy the same volume as the diesel. The second option is the easiest and most economic. At the end, this boat should be powered by sail except for short times under engine power.