parallel hybrid for propulsion

[Group9]

Definitely the most likely way to do things in the future as technology improves by leaps and bounds.

One of my neighbors has already done this on his Morgan O/I 41. Weird to see him ghosting through the harbor.

[mbianka]

Originally Posted by Allio

here's a relatively novel approach to propulsion I came across the other day. This would be my fantasy system aboard but it's expensive

Seagoing Hybrids - Hybrid Electric Marine Propulsion

So you can motor as normal, motor all electric, operate as generator only, generate from the prop while sailing.

Good range of engine sizes and retrofit capable.
No, i'm not connected...

Just wondering if anyone had any experience with this or similar setup?
allio

Allio:
They only problem with this system is that there is still a diesel engine involved. I converted to electric propulsion six years ago and never looked back and would never go back. I do have a Honda 2000 gas generator I use on deck for charging the battery bank after arriving at anchor as well as propelling the boat on rare windless days in a hybrid mode. Longest hybrid trip was about 40 miles so far. Could have done more but, reached my destination. Maintenance cost have been near zero (oil changes for Honda generator being the only real costs). Electric propulsion does work very nicely on a "sailboat". I'm just glad I no longer have a diesel on board too!

[mbianka]

Originally Posted by Cotemar

I agree.

Why would you want to slow your sailboat down to generate power? I want to sail as fast as I can go.

Let the solar panels and generator’s charge the batteries

No need to slow the boat down. You can do things with electric propulsion you would not do with a diesel. In light winds I set the control at around 10 amps current draw. Spins the prop slightly and negates prop drag and gives a nice bump in speed and is QUIET! Who needs a folding prop? As the wind pipes up current goes down until at around 6 knots I start recharging back into the battery. Beautiful thing to watch the boat making fuel while under sail.

[Cotemar]

Originally Posted by mbianka

No need to slow the boat down. You can do things with electric propulsion you would not do with a diesel. In light winds I set the control at around 10 amps current draw. Spins the prop slightly and negates prop drag and gives a nice bump in speed and is QUIET! Who needs a folding prop? As the wind pipes up current goes down until at around 6 knots I start recharging back into the battery. Beautiful thing to watch the boat making fuel while under sail.

What kind of boat and motor?

[mcarling]

The speed loss due to regeneration is often overstated. Below hull speed, the speed loss is significant, but at hull speed it is negligible. The reason is that once hull speed is reached vast amounts of additional wind energy are needed for minor gains in speed. The corollary is that a minor increment of speed can be given up for the utilization of vast wind energy for regeneration.

I would much rather give up 0.1 knots than run a diesel generator.

[Cotemar]

This Catamaran Diesel / Electric Hybrid system seems to make sense.

Cat Hybrids - Hybrid Electric Marine Propulsion

[barnakiel]

Originally Posted by mcarling

The speed loss due to regeneration is often overstated. Below hull speed, the speed loss is significant, but at hull speed it is negligible. The reason is that once hull speed is reached vast amounts of additional wind energy are needed for minor gains in speed. The corollary is that a minor increment of speed can be given up for the utilization of vast wind energy for regeneration.

I would much rather give up 0.1 knots than run a diesel generator.

You are not talking cruising boats, are you.

How many cruising boats go at their hull speed and how often does it happen. (No question mark, intentional)

When a sailing, displacement hull, boat goes at her hull speed there is already quite some load on her rig. In fact, I will risk some and propose that going at hull speed in a cruising context may be going a notch to fast.

And you can't be talking of the typical cruising prop either. Otherwise why will so many cruisers go for expensive things like Gore, Brunton and Max?

My experiences teach me otherwise: Few cruisers have props that can be effectively used for regeneration, not many cruisers will devote ANOTHER decimal of a knot to get some extra juice. They will start the genset. Bet?

b.

[pdf27]

Originally Posted by barnakiel

My experiences teach me otherwise: Few cruisers have props that can be effectively used for regeneration, not many cruisers will devote ANOTHER decimal of a knot to get some extra juice. They will start the genset. Bet?

Actually, that's one of the major benefits of a parallel hybrid system. Belt-driven alternators are only about 50% efficient at turning mechanical energy to power, and aren't big enough to load an engine into it's most efficient zone (~50% power).
However, if you have an electric drive available on the same driveshaft then it can run as an ~80% efficient generator. That means that, at worst you can charge the batteries as efficiently as a generator whenever you aren't at full power. However, for low power use diesel engines are horrendously inefficient - most of the fuel goes to turning over the engine, not the propellers. Having an electric motor in parallel allows you to do this low speed manoeuvring under electric power, or add load to the engine so it is operating in it's most efficient zone. Indeed, most parallel systems have large enough generators that the main engine becomes as efficient as a generator for charging batteries - with the advantage of doing so while motoring becoming one of reducing run hours rather than saving fuel (larger battery banks do the same thing, and are essential to take full advantage of the faster charging capability).

So regeneration is a little bit of a red herring here - great if it is actually used, but the benefits actually come from battery charging and low speed manoeuvring.

[nimblemotors]

The prius-like hybrid's main advantage is to be both a generator and/or electric drive and any amount of either, so you can use full electric propel, half engine power, half electric drive or engine power to charge AND propel, or engine charge while sails propel.
It is great design. Regen is not neccesary from the prop to make this worthwhile,
and as I've said better to just pull the prop from the water when underway if no electric or engine propel is needed to make sail power most effective.

I'd suggest having a wind generator, if windy enough to not need full sails or at hull speed, the wind gen will be cranking out power, and it works at anchor.

[mcarling]

Originally Posted by barnakiel

You are not talking cruising boats, are you.

How many cruising boats go at their hull speed and how often does it happen. (No question mark, intentional)

When a sailing, displacement hull, boat goes at her hull speed there is already quite some load on her rig. In fact, I will risk some and propose that going at hull speed in a cruising context may be going a notch to fast.

And you can't be talking of the typical cruising prop either. Otherwise why will so many cruisers go for expensive things like Gore, Brunton and Max?

My experiences teach me otherwise: Few cruisers have props that can be effectively used for regeneration, not many cruisers will devote ANOTHER decimal of a knot to get some extra juice. They will start the genset. Bet?

b.

In the past four weeks, I've been at hull speed on three different days with three reefs in. Your mileage may vary.

[mbianka]

Originally Posted by Cotemar

What kind of boat and motor?

Nonsuch 30U (8 tons) using a LEMCO 200 motor.

[barnakiel]

Originally Posted by pdf27

(...) So regeneration is a little bit of a red herring here - great if it is actually used, but the benefits actually come from battery charging and low speed manoeuvring.

Roger that. Some engine makes sell genset modules mounted on the main engine. Another good solution for power hungry systems.

b.

[SVNeko]

Most boats can't pull their prop from the water. Is there a way to disable the regeneration function and allow the prop to spin freely?

[pdf27]

Originally Posted by SVNeko

Most boats can't pull their prop from the water. Is there a way to disable the regeneration function and allow the prop to spin freely?

Three of them I can think of:
1) Fit a feathering prop - that'll have lower drag than a fixed prop freewheeling.
2) Send a small amount of power to the motor. Think about it, the prop is capable of adding power to the water or extracting power from it. Setting it at the right number of revs should draw effectively zero power.
3) Install a clutch between motor and propeller.

[mbianka]

Originally Posted by SVNeko

Most boats can't pull their prop from the water. Is there a way to disable the regeneration function and allow the prop to spin freely?

My EP system does that normally if I don't engage the regen function.