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Old 07-13-2014, 07:11 PM   #1
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"Get Me Home" system

Wondering what redundant power systems you use for emergencies.
I'm interested in knowing what the feasibility of a genny shaft.
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Old 07-13-2014, 07:18 PM   #2
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Others may know about a "genny shaft" but I have a 56 horse Yanmar with its own shaft as a wing engine. A bit of extra maintenance but very comforting.

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Old 07-13-2014, 07:52 PM   #3
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Old 07-13-2014, 08:37 PM   #4
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If you have an easily driven boat a OB may work. I used OB drive 9.8 with pusher prop on a 40 ft pilgrim and a 38 ft True North. You may have to use a little imagination to get a bracket. both boats moved over 4K. OB was used for dinghy so no added baggage.
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Old 07-13-2014, 08:51 PM   #5
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A 48Hp yanmar with a v drive and it's own dedicated shaft, and fuel tank. It has a gori 3 blade folding prop.
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Old 07-13-2014, 09:02 PM   #6
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TowBoatUS is my get home system.
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Old 07-13-2014, 09:06 PM   #7
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A 48Hp yanmar with a v drive and it's own dedicated shaft, and fuel tank. It has a gori 3 blade folding prop.
I can one up that. A 3ooHP JD on a straight drive with a four blade prop. Some time I am not certain if the get home is the port or starboard engine.
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Old 07-13-2014, 09:37 PM   #8
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Last boat had twins, current boat has a wing engine. Gen power is a possibility, but I'd look closely at how much HP you can pull out of it via electric, hydraulic, or direct drive, and see how well that can actually power your boat. Just look at how many HP the gen produces, then see where that falls on your main engine's prop curve to see what main engine RPM is the equivalent HP. That's how fast the boat will go, more or less. As one example to give some context, my 20KW generator has a 30HP motor driving it, but my wing engine is 80HP. The generator wouldn't move the boat more than 2kts or so, which with any current, wind, or waves means you aren't going much of anywhere. It would be better than nothing, but not by much.
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Old 07-13-2014, 10:06 PM   #9
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Just look at how many HP the gen produces, then see where that falls on your main engine's prop curve to see what main engine RPM is the equivalent HP. That's how fast the boat will go, more or less.
Assuming, of course, that the gen power was proped correctly whether the power was through PTO shaft, electric motor or hydraulic motor. I don't know what the formula would be for taking say...10 HP out of a genset get-home, but the machinery tax from a direct drive PTO would be one tax, an electric driven motor would be another, and a hydraulic drive off the PTO would be another....maybe all ending up with different HP at the prop. A comparison would be very interesting, but I'd bank on a direct drive PTO shaft to prop as the most efficient, electric as second and hydraulic as third most efficient.

Eyschulman: That's very good info. My Manatee is probably about as easy to push as your Pilgrim, but I'm surprised that you can get 4 knots that way. I plan to pick-up a 26 HP Yanmar Diesel outboard when I begin cruising in the Islands. Purchasing here in the US is a no-no, but sent to the Islands, no problem. Until then, I may just hang that 9.9 Merc off the transom and see what it can do. Maybe it's enough, but it'll still use gas, and my Admiral hates carrying gas aboard.
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Old 07-14-2014, 01:41 AM   #10
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Hello Larry... just a reminder, but I think Ted and Sarah aboard Manatee has a terrific set-up and it definitely works. The universal joint is key, but you might want to revisit the article and see if it would work for your Manatee.

Janice142 article Manatee Moves

I'm definitely thinking about a second means of propulsion for my Seaweed. An outboard would work well for me. According to Victoria Propeller, Marine propeller sales, service, and design (The Prop Shop calculator) -- Seaweed requires just 8hp to go hull speed. I'm curious though as to if an 8hp outboard would do the same as an inboard?

The Schucker mini that sold in the Carolinas and is now in Canada (if memory serves me) well, back in the Carolina days, she had a 5hp off her transom. It was an interesting set-up.

That's neither here nor there. For now it's all speculation on my part. Good luck with whatever you decide. Ted dreamed up that rig, and I'll admit to a bit of propulsion envy!
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Old 07-14-2014, 04:01 AM   #11
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Bay Pelican has a 27hp Yanmar with its own drive, three bladed Max Prop, and a separate fuel system/ tank and lines. Obtain 4 kts in calm water. Frequently exercise this motor as part of normal maintenance. Usually when coming into or going out of an anchorage we switch to the Yanmar just to exercise it. 350 hours in 15 years.

Familiar with a couple of boats with a power take off from the generator and the owners are unhappy with the set up. Using a generator connected to the main drive, the generator must be much larger than otherwise needed, the system is not used unless an emergency occurs and the system relies upon the same drive shaft and prop as the main engine.

Whatever you do a get home system needs to be used regularly in order to keep it operational.

Bay Pelican's get home system serves also as a back up generator, with a 125 amp alternator at 3/4 US gallon per hour of diesel. Also serves as a second engine for docking as its prop walk is the opposite of the main engine.
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Old 07-14-2014, 11:10 AM   #12
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I think the expression "get home" is misleading. It's very existence implies you should have a way to get back to your home port should your engine quit. Too much money, boat space, weight and extra maintenance is required to do that.

One should focus on;
1. Getting to a safe place.
2. Knowing what is wrong.
2. Getting parts or service to the boat.

In Alaska I thought in terms of survival but down in WA I'm thinking of avoiding the high cost of a tow or going hard aground in a very bad place. Your anchor and rode won't get you home but if you have a long one of light nylon (say 500'+) you may save the day or even your boat in bad conditions. Staying off the rocks can be 99% as good as "getting home".
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Old 07-14-2014, 02:27 PM   #13
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Just a thought. If you have a dinghy and a half-decent outboard, why not use that? Tie the dinghy off to one side using a painter going to a forward cleat and a towing strap to a stern cleat. You'd have to lash the tiller straight. Fire it up, put it in gear, and go back aboard to steer using your rudder(s).

I don't think my 4HP outboard will do much. Certainly not if there's any wind or current. But I'm thinking if you got up around 10HP or more, you might just be able to navigate to safety.
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Old 07-14-2014, 02:50 PM   #14
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Hello Larry... just a reminder, but I think Ted and Sarah aboard Manatee has a terrific set-up and it definitely works. The universal joint is key, but you might want to revisit the article and see if it would work for your Manatee.
Seeing what they've done (and how long they've been doing it, not to mention how far they've gone with it), one might take their example and follow suit, but now that I've gone to the expense of the new veranda hatch and moving the genset there, some other options exist. The dinghy they have looks like a new one compared to some of the old photos I've seen when they were only in the "teens" of completed loops. I heard from someone that they lost the old dinghy in a storm down island. Do you know if there's any truth to that? That boat has a massive mast and boom, R/V Air Conditioner, much bigger hand rails, a huge cradle for the dinghy. That's all well above the CG, and sometimes they hoist that heavy dinghy up on that cradle. Here I am, counting pounds and ounces added above the CG on everything I do, and this guy is out there doing blue water!

I dunno. I guess I should stop worrying so much about disturbing the boat's stability. I wonder how much it cost to customize the dinghy that way. If it was less than the Yanmar Diesel outboard idea, maybe I'd go for it.
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Old 07-14-2014, 02:56 PM   #15
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I've pondered getting two electric trolling motors and fashioning clips on transom so they could be clipped in. Might get 2kts as long as not upwind or against seas or current. But it would be enough to get..... somewhere. I think. A big batt charger off gen, or if main can run, that would do it.

It would be something I could leave at the house unless venturing far.

Since my boat is planing, weight is critical.
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Old 07-14-2014, 06:53 PM   #16
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I think you first need to do some honest cost-benefit analysis. If a boat were originally designed with a get-home system, then it's probably worth keeping. But adding something? The cost of complete redundancy (separate fuel, means of starting, engine controls, instrumentation, cooling and exhaust, and the ultimately important prop and shaft) would be substantial. eyschulman's comment about twin main engines is just the opening salvo in the single versus twins debate. If the get-home doesn't work in, say, 20 knots of wind...or if it makes it more difficult to maintain the main engine...or if it introduces new ways for the boat to take on water - you really have to weigh that against the likelihood of actually using it in under the anticipated conditions.

This kind of reminds me of the guy on the C-Dory forum who had a fear that his hull might fail, and wanted to get advice on how to mount an inflatable RIB-like skirt around the boat to inflate in case he got holed.

My boat doesn't have a get-home system, and I wouldn't be very interested in trying to install one. I'm sort of like manyboats on this - I have towing insurance and multiple anchor setups. I also have the notion that the best backup is a 2nd boat - that's a big reason why I carry such a substantial tender (that and the Admiral likes 'em big!).
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Old 07-14-2014, 07:35 PM   #17
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This kind of reminds me of the guy on the C-Dory forum who had a fear that his hull might fail, and wanted to get advice on how to mount an inflatable RIB-like skirt around the boat to inflate in case he got holed.

I also have the notion that the best backup is a 2nd boat - that's a big reason why I carry such a substantial tender (that and the Admiral likes 'em big!).
Tell the guy with the C-Dory that a Uni-fender is the way to go (photo below). What size tender to you carry, by the way?
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Old 07-14-2014, 07:51 PM   #18
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Tell the guy with the C-Dory that a Uni-fender is the way to go (photo below)
Nice! How large is the compressed air tank to inflate that?
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What size tender to you carry, by the way?
Nautica 13.5 Widebody with a Yamaha 50 Hi-Thrust. The davit started life as a Roskelly-Olssson but was hugely modified. It tucks up nice against the stern but the 6'9" beam - and 15' overall length - make fendering a real chore so we usually tow it except when doing all day passages.
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Old 07-14-2014, 08:45 PM   #19
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I think the whole get home thing totally depends on where you are trying to get home from, both in terms of distance and remoteness. If you are coastal cruising in populated areas, just call tow boat US. Insurance and whatever other fees you pay will be way cheaper than another engine/mechanism, and way less maintenance. Situations like this are also where outboards, dinghies, and other clever gadgets can help, not to mention twin engines.

But if you are hundreds of miles off shore, or perhaps a thousand miles, you really need a backup that can carry you that longer distance. And it needs to work in high seas. That pretty much eliminates any push or pull with a dinghy, even if you had enough gas on board to run it for more than a few hours. I think the only viable options are a) twins, b) a wing engine, or c) a hydraulic or electric drive powered by a big generator.
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Old 07-14-2014, 09:30 PM   #20
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[QUOTE="twistedtree;249930"

But if you are hundreds of miles off shore, or perhaps a thousand miles, you really need a backup that can carry you that longer distance. And it needs to work in high seas. That pretty much eliminates any push or pull with a dinghy, even if you had enough gas on board to run it for more than a few hours. I think the only viable options are a) twins, b) a wing engine, or c) a hydraulic or electric drive powered by a big generator.[/QUOTE]

Don't forget the dirty word, 's**l.'
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