Get home propulsion - strange ideas

Bay Pelican, a 42ft Krogen made 4.5 knots in relatively calm waters using a 27 hp wing engine with a max prop.

Lou, You were on a good track, just adding tidbits...

DDW said:

I think you could do that with a cog belt, which would be easily untensioned/removed. The complication is you would be driving the transmission (and many of them don't like this), and the prop and shaft have to be serviceable. None of those are a problem with the outboard.

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In an emergency, I might accept the cost of tranny repair/replace.....or buy, modify the tranny that it will work.

Singles with protected shafts and props, be it the first point of damage usually survive well enough to be put back into service as long as not so large to be unmanageable with common tools.

Not sure what size boat we are talking about "getting home". My experience with a 47ft Selene (60K lbs) is that a 65HP Yanmar Saildrive wing engine (folding prop) managed about 4 kts in calm seas. Figured it would probably help in rougher conditions but would be very slow. So for sake of argument let's say that the minimum HP that is even worth considering is 25HP. That converts directly to 18.6KW. Now figure a (best guess) 80% power conversion from generator, direct to electric motor (no battery), to propeller. So to achieve the rated 25HP, you now need a 23KW generator hard wired to the motor. Proportionally, a 5KW generator would at most provide about 5HP. Hard to see it doing much of anything - can barely move a large dinghy. Batteries will not help because the charging cycle wastes power and is too slow to keep up with the power demand.

I thought there was an option with Dickson stern thrusters to rotate them 90 degrees and use them for propulsion...
Dickson Thruster - Stern Thrusters

Chrisjs is right. When I looked it always came out to be needing too much hp for wing propulsion for it to work ideally as a gen or perfect gen size and not enough hp for propulsion. Weather hydraulic or electric.

psneeld said:

Singles with protected shafts and props, be it the first point of damage usually survive well enough to be put back into service as long as not so large to be unmanageable with common tools.

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I'm not sure I can swing hand tools underwater (50 deg water) with enough force to do any good, even if I had the dive gear onboard.

At low enough speeds, essentially all drag is viscous friction. With this scheme you'd need to forget about a convenient retrieve in time to make your dinner reservation. That's wing engine territory. I'm pretty sure I can push this trawler (34') by hand at 2 knots in calm conditions, and that's not 160 lbs. Even 2 knots is a long way in a day. Many have crossed the Atlantic at that speed. You'd need calm conditions. I guess I need to borrow a trolling motor and try it. Trolling motors have flat pitch, built for static or low speed thrust. Most outboards are not.

I don't think anything involving batteries is workable - they take for longer to charge than discharge in this application.

psneeld said:

Lou, You were on a good track, just adding tidbits...

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L

Swing hand tools underwater?


Ok, enough said.......

Not too long ago there was a very nice Willard 40 listed at Boatshedseattle.com that was equipped with an electric get-home drive. The listed displacement was 33,000lbs.

From the listing:

"An 7.5 HP 3 phase 220v electric motor is installed with belt drive to the shaft providing for "get home" power in the event of a problem with the drive engine. The Onan MDJE-18R diesel generator provides 7.5KW 3 phase power for the get home motor and 5KW single phase for house loads. The get home motor provides steady drive forward at about 5 knots in calm water."

IIRC, to use, the belts were placed around the pulleys and were tensioned with the large adjusting screw in the foreground. The motor base was hinged on the opposite side. Not the easiest 'engagement' but better than oars I guess.

I read somewhere that some W30's were also fitted with this option from the factory, but I was never able to substantiate this.

I just bought an E-Propulsion Spirit 1.0 for my new Dinghy. Nice piece of gear and an improvement over the Torqeedo design IMO. It has an integrated (removable) battery of 40V and 1000amps, 3hp equivalent and 66lbs of thrust. They also make a line of higher Horsepower OB Units (the Navy series) in 6 and 10 HP. The Lithium Polymer 60V battery for those is outrageously expensive though...

Check em out: Electric Outboard | ePropulsion

Heron said:

I just bought an E-Propulsion Spirit 1.0 for my new Dinghy. Nice piece of gear and an improvement over the Torqeedo design IMO. It has an integrated (removable) battery of 40V and 1000amps, 3hp equivalent and 66lbs of thrust. They also make a line of higher Horsepower OB Units (the Navy series) in 6 and 10 HP. The Lithium Polymer 60V battery for those is outrageously expensive though...

Check em out: Electric Outboard | ePropulsion

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Interesting outboard.

I think you're mistaken on the 1,000 amps. They list the battery as 1KW, which is 1,000 watts.

Ted

psneeld said:

Swing hand tools underwater?


Ok, enough said.......

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Well, that's where the bent/broken bits are going to be. If I'm close enough to a boatyard to get a haulout, then I certainly don't need the outboard! Might be possible to beach the boat at high tide, work on the gear, then refloat, but that has a range of hazards.

LarryM said:

"An 7.5 HP 3 phase 220v electric motor is installed with belt drive to the shaft providing for "get home" power in the event of a problem with the drive engine. The Onan MDJE-18R diesel generator provides 7.5KW 3 phase power for the get home motor and 5KW single phase for house loads. The get home motor provides steady drive forward at about 5 knots in calm water."

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There's the proof of concept. 5 knots is almost cruising speed!

I remember we had diesel outboards being trialed on one of our work boats on a salmon farm in southern Tasmania in 1996 ran beautifully but wouldn't pull the skin off a custard they have been around a long time.

Here is a 300 Hp one. http://www.boatsales.com.au/editorial/details/300hp-oxe-diesel-outboard-arrives-in-australia-110350/

Keep in mind that if you break down near land you can call for help and the get home is of much less value/concern. But if you break down far away, you need a get home that can work in adverse conditions and can run for days. So it seems like somewhat of an all or nothing proposition.

I'm not going that far from land, but near land doesn't mean help is at hand. The most recent place I've been that this was true was the north west side of Vancouver Island. For several days we saw no one at all, no cell coverage, and VHF was very spotty. Even with a sat phone, getting a tow from there to the nearest travel lift is many days and a small fortune. You'd find the limits of your "unlimited tow" membership very quickly. But a weeks run at 2- 3 knots would but you near help. A small outboard would do that pretty easily, if only the fuel were available. Just need to turn diesel into propulsion some how.

Anybody remember these?

27HP Yanmar Diesel Outboards

I don't think they were ever sold in the US, but what about a used or rebuilt one purchased abroad. Apparently they are available rebuilt from Apollo Duck in Lithuania. They were available in 18, 27, 36 and 40HP models.

Yea, I know, too much time on my hands tonight . . . .

I do not think it is practical to retrofit an inshore boat to do much more than stagger a bit with a dink pushing on the hip.

For an offshore cruiser ,far more costly and complex, the concept would be getting the most service from what is installed.

A diesel aux engine could power a hyd pump and a large (250A-24V DC ) coach alt.

This would charge a huge house batt set easily and if monitored quickly..

For emergency propulsion the hyd pump could spin a Paul Luke 2 blade prop with good diameter and enough blade area to move the boat modest speeds .
These are not racing sailboat props , but built for this style service.

The hyd pack could easily power a generator head for air cond.

It would also power the thrusters and windlass and any dink or anchor cranes aboard.

A hyd pump on the propulsion engine could also power these loads , the hyd would be sized to operate the generator head during cruiseing.

Advantages , the wing or aux engine would get plenty of use so should require less maint.

The thrusters would operate at full power with the main engine at idle.

Would not be a big deal to create with OTS parts .

Next boat perhaps?

O C Diver said:

Interesting outboard.

I think you're mistaken on the 1,000 amps. They list the battery as 1KW, which is 1,000 watts.

Ted

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Yup, Correct Ted...slight Brain infarction there...

Or, to take the get home idea another direction, you could rig a simple kite-surfing kite. This discussion seems to agree one could get around 5hp out of a kite, with enough wind.

http://www.kiteforum.com/viewtopic.php?t=2376805

“Same kite as in example (1.), attached to a Honda Civic with tires overinflated to reduce resistance, on a broad reach on an airport runway, with wind blowing like !@#$%, chicken loop mechanically fastened to car (pilot couldn't possibly hold it), going 50 mph with 40 lbs resistance (rolling resistance only, apparent wind over the beam): power = 5.3 hp”

I always wondered about using a electric motor out of a ac forklift when I was working on them for a purpose like this.

I'd normally shy away from hydraulics due to their propensity to leak, but in a complex offshore boat a hydraulic aux motor might make sense. I'd probably go with mechanical drive on the largish gen set if building from scratch, fewer maintenance issues.

The smallest Yanmar was 18hp, and quite heavy if I remember. There seem to be some around the world working on lighter ones. I'd be happy enough with the dink pushing on the hip, I think it would do what I want - till I ran out of fuel in a couple of hours. Plenty of diesel though.

A kite would get you somewhere downwind, if there was wind. In the PNW, no reliable wind, anytime there is some it always seems to be going the wrong way. Also a kite requires someone to fly it usually. There have been some automated controls experimented with for use in propulsion, but a large kite and hardware may cost as much or more than a small diesel, and is more fragile.

Heron said:

I just bought an E-Propulsion Spirit 1.0 for my new Dinghy. Nice piece of gear and an improvement over the Torqeedo design IMO. It has an integrated (removable) battery of 40V and 1000amps, 3hp equivalent and 66lbs of thrust. They also make a line of higher Horsepower OB Units (the Navy series) in 6 and 10 HP. The Lithium Polymer 60V battery for those is outrageously expensive though...

Check em out: Electric Outboard | ePropulsion

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Looks nice. I have an older Torqeedo and agree that the Spirit does look like it has taken the Torqeedo and made some improvements.

The Navy looks like it would be a very nice alternative to a small gas outboard. The issues of course are cost and range.

For the larger boat the 18ft Boston Whalers have had diesel IO installed

.Almost unlimited range .

Heck of a dink!!

When the Liquid Piston diesels become available , a 50 lb 40 HP engine may solve lota of hassles


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Ok. Something totally off the wall. What about a parasail chute? They seem to be pretty good size and cost doesn't look terrible. With a little work you could probably get two going at the same time.

TowLou said:

I always wondered about using a electric motor out of a ac forklift when I was working on them for a purpose like this.

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That's exactly what the young fellow of the Sailing Uma youtube videos DIY'd on his sailboat.

Simi 60 said:

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This was the idea I had with the rigging a regular kite-sailing kite to the boat somehow, but it may require constant attention to keep it flying, and that would be tiresome.

cardude01 said:

This was the idea I had with the rigging a regular kite-sailing kite to the boat somehow, but it may require constant attention to keep it flying, and that would be tiresome.

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Not as tiresome as rowing