"get home" systems

In my previous post "disappointed with twin screw fuel economy", there was reference made to "get home" systems, used mostly by single screw trawlers in an emergency to run the prop from the generator. The 2 links shown below were referred to in that previous thread. If you know of more information on the internet about "get home" systems, I would love to learn more. Thanks.

The Get-Home System: Do You Need One And What Are The Options? | PassageMaker

http://www.wesmar.com/pdf/APU/apu_brochure_web.pdf

Great references, seattleboatguy. I've seen many single screw trawlers with get home outboards. I have seriously contemplated adding one to mine (4HP to 6HP long shaft would probably suffice for my boat in an emergency) but the additional hardware would ruin the look of my girl's rear!

During our recent boat search we looked at one boat that had a 3 phase generator and a 3 phase 20hp electric motor that was able to connect to the propeller shaft via a belt and pulley. Have to see if I can find it again.

For an offshore cruiser I would choose HYD.

So many items are far better powered (windlass , thrusters ) that it would be worth the effort.

6KW is easy to obtain with a relativly cheap hyd gen head that could be powered off the main engine or noisemaker. The noisemaker could power the shaft , or for the real belt / suspenders folks, a folding sailing prop that could also be powered with the main engine should the shaft system fail.

Not much that cant be run with Hyd , and if overloaded the white smoke never comes out.

Compare the cost of a get-home system to the cost of a really full set of spares for a main propulsion engine: starter, water pump, lift pump, water hoses and fuel lines, etc. as well as the normal periodically replaced stuff like impellers, fuel filters, and so forth.

And really good towing insurance

I've read most diesel problems originate in the "bolt ons." If true, and if traveling within range of the tow boats, spares can be lots less expensive than extra engines/props/etc.

-Chris

I still dream of a day when a simple diesel outboard would be EPA approved here. Expensive, but easy to sell or transfer to a future boat, not to mention, a capable (albeit heavy) dinghy motor.

No tow service where we live, so we got a 9.9 Lehr propane outboard on a swivel bracket with a fibreglass 20 lb tank...haven't needed it yet but happy that it's back there, always ready to go, even in winter, just in case.

healhustler said:

I still dream of a day when a simple diesel outboard would be EPA approved here. Expensive, but easy to sell or transfer to a future boat, not to mention, a capable (albeit heavy) dinghy motor.

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I agree. I would prefer diesel outboard as my first choice, but will go with extensive spare parts for main engine for my future passage plans.

Also, in my many year search, i never found a twin engine boat that was less than 50% more fuel consumption. (1.5 gal for my KK42, versus 2.2 gal for the best twin)

Richard on Dauntless
Southbound and Down

Out of curiousity have you tested this setup, how does it perform?

MurrayM said:

No tow service where we live, so we got a 9.9 Lehr propane outboard on a swivel bracket with a fibreglass 20 lb tank...haven't needed it yet but happy that it's back there, always ready to go, even in winter, just in case.

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ranger42c said:

Compare the cost of a get-home system to the cost of a really full set of spares for a main propulsion engine: starter, water pump, lift pump, water hoses and fuel lines, etc. as well as the normal periodically replaced stuff like impellers, fuel filters, and so forth.

And really good towing insurance

I've read most diesel problems originate in the "bolt ons." If true, and if traveling within range of the tow boats, spares can be lots less expensive than extra engines/props/etc.

-Chris

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Except that this misses one of the most common failures - the exposed prop and shaft. I would hate to be in my engine room trying to fix the diesel out in open water with no control of the boat. At least a get-home setup will allow the boat to make headway. I agree with the PM article that using an offset wing engine is tough on the autopilot. When I putting hours on my wing engine I can only get mine to stay on course with the AP in calm water after manually compensating for the offset.

Dave

Wxx3 said:

Also, in my many year search, i never found a twin engine boat that was less than 50% more fuel consumption. (1.5 gal for my KK42, versus 2.2 gal for the best twin)

Richard on Dauntless
Southbound and Down

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We usually find what we want to find. For a KK 52 I have seen the boats and data to support no more than a 10 per cent differential when comparing a single JD 6068 to two JD 4045s. In fact at several speed ranges they were identical.

I've a friend with the last KK 42 made. He has cruised both coasts extensively with nary a let down on his JD single. Another friend has had his single Selene, with a get home setup also, towed back to safe harbor. Lots of stories out there to chuckle about.

The penultimate single engine ocean voyager, Dashews FPB 64, have very nice get homes. The earlier ones did not and were retrofitted. With the get home only running they track true with AP.

magicbus said:

Except that this misses one of the most common failures - the exposed prop and shaft. I would hate to be in my engine room trying to fix the diesel out in open water with no control of the boat. At least a get-home setup will allow the boat to make headway. I agree with the PM article that using an offset wing engine is tough on the autopilot. When I putting hours on my wing engine I can only get mine to stay on course with the AP in calm water after manually compensating for the offset.

Dave

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Hi Dave,

When I'm running the wing engine, I switch the Autopilot to "Work" mode, and it does much better at running in a straight line. My understanding is that "work" mode is for situations such as towing alongside, telling the AutoPilot to try harder because you are in a situation requiring finer control. YMMV

I also agree that one of the benefits of a wing engine is the completely separate fuel system, engine, shaft and propeller. It allows you to keep the boat off the rocks, pointed into the weather while you deal with whatever stupid user mistake caused the main engine to stop....

The Eagle has a hydraulic get home. The gen set Perkins engine drives the hydraulic pump which drives the hydraulic bow thruster but the lines can be switch to drive the get home. The get home is connected to the main shaft with a sprocket chain drive. The gen set is set at a fixed 1800 rpm, so the hydraulic pumps is varible psi from 0 to 1500 psi that is controlled by a cable from the pilot house. The pump also has an electric drive, so when no used it free spins. I have connect the get home only once and we got some head way, maybe 3 to 5 knots.

The hose is rated to 3000 psi and the and bow thruster hydraulic drive to 2500 psi. The limiting factor is the gen set engines HP. When we bought the Eagle the hydraulic pump had the electric clutch but a fixed PSI. The sudden PSI made the hoses jump which made me jump, so changed the hydraulic pump to a variable psi, and re sheaved the gen set to maximize the hydraulic pump RPM and PSI. The sytem has a 15 gallon reservoir tank so the pump can run for hours at a time.

Bay Pelican's get home engine is a Yanmar 27 hp offset to starboard with its own shaft and prop. The fuel supply comes from the main tanks through the same manifolds as the main engine. This is one weakness which I may get around to curing in the future with a separate small tank for the wing engine.

Our cruising grounds has no tow service at all, so its get home by yourself or get help from another boater, 19 out of 20 of which are sailboats.

Marty

hydralic system

Many years ago I had a hydralic system on my boat. It was mounted like a transmition on to a westerbeke. A get home moter was mounted above the shaft with a heavy timing style belt. I also had a hydralic anchor windlass, with refer comp and scuba comp run with hydralic motors. The system was designed so the motors would hold a set speed even if both were run at the same time. There was also a pump run off the main engine thru a magnetic clutch. This system worked very well. I never had to use the get home driver even with two trips Fiji to Australia. My first real post on TF hope it is OK.

Marlinmike said:

Out of curiousity have you tested this setup, how does it perform?

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We haven't given the Lehr 9.9 a full blown test yet, as in finding speed over ground in neutral conditions, just noodled around a bit to get a feel for it. It's #1 job is to get us out of immediate danger and to a safe anchorage where we can attend to whatever happened if we lose the main engine.

magicbus said:

Except that this misses one of the most common failures - the exposed prop and shaft. I would hate to be in my engine room trying to fix the diesel out in open water with no control of the boat. At least a get-home setup will allow the boat to make headway. I agree with the PM article that using an offset wing engine is tough on the autopilot. When I putting hours on my wing engine I can only get mine to stay on course with the AP in calm water after manually compensating for the offset.

Dave

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Yep, agree. Another potential problem might be bad fuel, although that's perhaps sometimes manageable with filtration and even polishing for some, etc. OTOH, it could also affect a get-home, too, depending on tankage...

Bouncing around in the open ocean while struggling to change a water pump or some such could indeed be a pain. Possibly attenuated with a sea anchor or drogue... but maybe not.

In any case. I wouldn't want to be there either.

FWIW, I meant my earlier remarks as a mention of another approach, another cost option to consider... along with various risk assessments... costs versus risk versus likelihood of risk versus potential mitigation of risk... and all that.

Not as a recommendation for course of action.

-Chris

Bob Cofer said:

During our recent boat search we looked at one boat that had a 3 phase generator and a 3 phase 20hp electric motor that was able to connect to the propeller shaft via a belt and pulley. Have to see if I can find it again.

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I recall reading about a Willard 40 that had that setup, if that helps you find it again.

MurrayM could have the reasonable available solution with the Propane unit on a bracket. Hopcar carries Lehr outboards, and my plan was to trade-out my 9.9 Merc for one anyway. None of these solutions are easy, but a simple outboard bracketed straight could give you the knots necessary for the rudder to be effective. Once within docking range, it could help maneuver the boat even in reverse right from the stern while 1st mate handles to bow thruster. In weather, it may be strong enough to keep the boat bow into the waves or current while working on the main.

Bob Cofer said:

During our recent boat search we looked at one boat that had a 3 phase generator and a 3 phase 20hp electric motor that was able to connect to the propeller shaft via a belt and pulley. Have to see if I can find it again.

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I believe you are referring to "Domino", a 40' Willard vintage mid 1970's(?). Interesting set up.

That's the one. Can't seem to find my info on it though.

The boat is in LaConner. The "get home" set up is the only one I've seen utilizing that system. Here is a link to her site:

Domino | Willard Boats

healhustler said:

MurrayM could have the reasonable available solution with the Propane unit on a bracket. Hopcar carries Lehr outboards, and my plan was to trade-out my 9.9 Merc for one anyway. None of these solutions are easy, but a simple outboard bracketed straight could give you the knots necessary for the rudder to be effective. Once within docking range, it could help maneuver the boat even in reverse right from the stern while 1st mate handles to bow thruster. In weather, it may be strong enough to keep the boat bow into the waves or current while working on the main.

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How much propane might it take to "get home" from somewhere out of tow boat reach?

-Chris

healhustler said:

MurrayM could have the "reasonable available solution" with the Propane unit on a bracket. Hopcar carries Lehr outboards, and my plan was to trade-out my 9.9 Merc for one anyway.

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What he said...

32' Fishing boat in Alaska. The OB is used for slow trolling for Salmon.

ranger42c said:

How much propane might it take to "get home" from somewhere out of tow boat reach?

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Word is that a 20 lb tank will last 5 hours wide open, and 14 hours at "cruising speed", which I'm assuming would be around 3 knots or so.

ranger42c said:

How much propane might it take to "get home" from somewhere out of tow boat reach?

-Chris

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That's a very good question, and the answer is "I don't know". My boat is a rather windy 36 ft. at around 24000 lbs.. I'd need a 9.9 or more to get anywhere with the outboard power, and the farthest I'd be from a tow would either be in the middle of lake Huron, Michigan, or in the Gulf Stream on the way to or from the Bahamas. Aboard in a normal situation, I'd probably have two 20 pounders and two 10 pounders in various stages of use. I'd likely fill them before a long transit or crossing. It would probably come down to something like how long I could run the engine at 80 percent. Maybe Hopcar has a spec' sheet on the 9.9 and 15 Lehrs. My boat is really easy to push below 6 knots. I'm guessing a 9.9 would give me 2-3 knots, and as soon as I can, I'll test my Merc. 9.9 on a bracket to verify that. Even so, there could be wind and current to nullify that forward progress. It would take 20 - 25 HP to be a substantial get-home system.

healhustler said:

That's a very good question, and the answer is "I don't know". My boat is a rather windy 36 ft. at around 24000 lbs.. I'd need a 9.9 or more to get anywhere with the outboard power, and the farthest I'd be from a tow would either be in the middle of lake Huron, Michigan, or in the Gulf Stream on the way to or from the Bahamas. Aboard in a normal situation, I'd probably have two 20 pounders and two 10 pounders in various stages of use. I'd likely fill them before a long transit or crossing. It would probably come down to something like how long I could run the engine at 80 percent. Maybe Hopcar has a spec' sheet on the 9.9 and 15 Lehrs. My boat is really easy to push below 6 knots. I'm guessing a 9.9 would give me 2-3 knots, and as soon as I can, I'll test my Merc. 9.9 on a bracket to verify that. Even so, there could be wind and current to nullify that forward progress. It would take 20 - 25 HP to be a substantial get-home system.

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The neatest set up I have see was post by you of a sister Krogan modified the stern deck so the dinky could be towed and/or push to be used as a get home. I remember it as I been thinking of towing our 19 ft run about with a 140 hp OP, which is more than capable of pushing/towing the Eagle if need by.

Hydraulic "get home" drive

I am in the middle of building my own generator/hydraulic powered main shaft drive system. My boat is a 40 Palmer full displacement trawler powered by a 6.5 liter Mitsubishi 6D14 putting out about 120 HP. The transmission is a Borg Warner Velvet Drive 72 that can free wheel. The shaft is 2"SS with a 24" prop which is very well protected by the deep steel keel. The main is an older motor, 4000 hrs since a major rebuild. Seems to be solid and I have talked to several boaters that claim these engines will run 20,000 hrs in fishing boats. But it is old. The boat does not have a gen set but has a compartment that will accept one, which is what got me thinking that if I add a generator, why not make it dual purpose to be able to run the main prop shaft. The boat only needed a 4-5 kw genset but as I got looking at specing out an engine, there is not much difference in size or cost to go to a 12 kw industrial generator to get up into 16 hp. The next leap was skip the AC generator and mount the Sundstrand 20 closed loop piston pump that I already had directly to the flywheel and bell housing and just belt drive the alternator of choice to keep the battery banks going. Another idea was to buy the Mitsubishi S4L2 diesel 4 cylinder with a variable governor, now that it is not primarily producing AC, which allows the same engine to produce up to 39 HP intermittently at 3000 rpm. This engine will produce 30 HP all day long at 22-2500 rpm and now is a serious driver for this boat and makes an awesome trolling motor. I got a hydraulics shop that would work with me and we did all the calculations involving cu. in./rev, output rpm, flows and psi and came up with using a Sundstrand style 23 series motor to complete the closed loop system. I have a 15 gallon reservoir and a big tube type oil cooler to plumb in and I should be ready to install it. The control of the drive motor is very simple and just involves a cable control to a lever on the pump that allows forward - neutral - reverse infinitely controlled in either direction. This is a high quality commercial system capable of 6,000 psi and 4,000 rpm so at the 2,000 psi settings and 2400 rpm that it will be operating at, it should have very long life. At this point I am planning on just sprockets and #60H roller chain to connect the motor to the flange coupler on the main prop shaft. I know there are fancier ways of doing it but that can come later if it works well. It will be pretty nice to just do a 5 minute chain master link connection and be under way again if needed.

Has any one any experience with doing something like this? Am I on the right track with what I have laid out as a plan here? Thanks for any input in advance.

I remember Steve Dashew designed a backup diesel and separate shaft/prop for his FBP Windhorse. Article here and here.

Transaxial said:

I am in the middle of building my own generator/hydraulic powered main shaft drive system....

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You gain redundancy for the engine but not if the drive system,ie shaft/prop/stuffing box or seal etc is the problem,a second shaft system would do that. But, a gain is a gain, hope it goes well.