Diesel outboard as 'get me home' option?

[BandB]

If I am 500 miles off shore I am in the wrong CE rated boat.
The percentage of folks like us being off shore 500nm is less than 1%, I am guessing

Because if you're not offshore or in some remote area, then the need for a get-home engine doesn't exist. This discussion is for the 1%. You never go anywhere you need one, nor does the OP, but he presents the scenario of halfway to Bermuda. That is anywhere from 300 to 500 miles off shore as Bermuda is 600 to 1000 nm depending on where one is leaving from. This is then a 1% question as I don't know many here going to Bermuda.

 

[DDW]

Not that many trawlers on the east coast attempt to go to Bermuda. But a significant percentage in the PNW go at least as far as the mid BC coast, certainly more than 1%, and that is remote even though protected. On the east coast, anywhere from say Cape Cod to Key West is practically swimming distance to a port.

 

[OldDan1943]

On the east coast, you cannot go out too far or you will get caught up in the gulf stream.

 

[BandB]

On the east coast, you cannot go out too far or you will get caught up in the gulf stream.

If you're going north you may welcome the Gulf Stream. Depends on it's mood.

 

[donpjr]

https://coxmarine.com/

300hp outboard Diesel.

 

[raised kk36]

I would say yes. When I first had my boat there were many fuel delivery issues. To get back to the dock 4 times, I lashed my dinghy with a 15hp outboard just stern of the widest beam. Worked great, one time pushing me at 3mph against a 2+ knot current for 14 miles. The hull shape of my boat won't allow a swim platform, let alone one that would be directly on the centerline.

 

[healhustler]

I would say yes. When I first had my boat there were many fuel delivery issues. To get back to the dock 4 times, I lashed my dinghy with a 15hp outboard just stern of the widest beam. Worked great, one time pushing me at 3mph against a 2+ knot current for 14 miles. The hull shape of my boat won't allow a swim platform, let alone one that would be directly on the centerline.

The Manatee swim platform can be done, but it isn’t easy. This one is also reinforced to hold a get-home outboard. At least one manatee is out there with a get-home outboard on a transom bracket.

 

[OldDan1943]

https://coxmarine.com/

300hp outboard Diesel.

That hp rating is almost as large as the hp of my Cummins 5.9.

 

[Jacques Raoul]

If sailboats have small engine, power boat should have emergency set up for sail?

 

[skyhawk]

If sailboats have small engine, power boat should have emergency set up for sail?

when I first started daydreaming about liveaboard cruising, the motor sailors caught my eye. Not so much as a "get home" option.... but I suppose that's part of it.
The more I dug though I came to the conclusion that so many folks before me apparently have come to....jack of all trades master of none
sorta like a hybrid electric car that's sort of a crappy EV that still holds all the disadvantages of a gas car...or is it a crappy gas car that holds only a few of the advantages of an EV

I still fundamentally sorta like the idea...and kite sails on a trawler hold my curiosity...but still not so much as primarily an emergency source

Just yesterday I heard something that I'd never heard before about that jack of all trades aphorism....and fits your post I think well
apparently the whole thing is this something like this
"a jack of all trades is a master of none, but is almost always better than a master of one."

 

[O C Diver]

I had a thought (it will probably die of loneliness). Part of the problem with smaller outboards for pushing trawlers stems from them coming out of the water in seas and lacking force to drive into waves. If you found an electric outboard or 2 that would push the boat in minimal weather, and you could maintain the batteries through the generator, would it be practical to only work your way to safety on good weather days? If you were crossing to Bermuda, would it be feasible as a backup plan to put the drogue out on the bad days and motor on the good ones? If in the PNW, motor on the good days and anchor until the next weather window?

Ted

 

[BandB]

I had a thought (it will probably die of loneliness). Part of the problem with smaller outboards for pushing trawlers stems from them coming out of the water in seas and lacking force to drive into waves. If you found an electric outboard or 2 that would push the boat in minimal weather, and you could maintain the batteries through the generator, would it be practical to only work your way to safety on good weather days? If you were crossing to Bermuda, would it be feasible as a backup plan to put the drogue out on the bad days and motor on the good ones? If in the PNW, motor on the good days and anchor until the next weather window?

Ted

I'm not sure about the small electric outboards, but the concept you propose of something small to motor in good conditions and holding position safely in bad conditions makes sense. If conditions are bad, the objective may well be just holding things together until they improve, not making headway. Now, even in that, fuel may become a challenge as even that likely uses some.

I think if you find yourself in 12' or more seas, even with a repairable condition, waiting things out until you can make the repair is often what you face. You can find a way to remain safe even while lacking propulsion and then address the propulsion issue separately.

Now if your solution gets you 2 knots on average, just keep in mind that will take 7 days if you're 300 nm from shore or 11 days if 500 nm but nothing wrong with that as long as safe and making progress.

 

[O C Diver]

I'm not sure about the small electric outboards, but the concept you propose of something small to motor in good conditions and holding position safely in bad conditions makes sense. If conditions are bad, the objective may well be just holding things together until they improve, not making headway. Now, even in that, fuel may become a challenge as even that likely uses some.
.

Epropulsion makes 9.9 HP outboards. I was thinking a pair of those on a 40' boat might push it between 3 and 5 knots. They might also work nicely on a RIB.

If the outboards were manageable to push the boat, I would assume there should be enough diesel to run the generator without running the main engine. Obviously one would need to do some runs to determine fuel consumption over a few days.

Ted

 

[DDW]

I had a thought (it will probably die of loneliness). Part of the problem with smaller outboards for pushing trawlers stems from them coming out of the water in seas and lacking force to drive into waves. If you found an electric outboard or 2 that would push the boat in minimal weather, and you could maintain the batteries through the generator, would it be practical to only work your way to safety on good weather days? If you were crossing to Bermuda, would it be feasible as a backup plan to put the drogue out on the bad days and motor on the good ones? If in the PNW, motor on the good days and anchor until the next weather window?

Ted

I'm not sure that would be practical mid-ocean, most cruising routes in the ocean have prevailing winds - though you could make better and more controlled progress downwind if you have steerageway. With currents and drift, you may give up a lot even with a parachute if trying buck the weather. I think it is practical in the PNW, when calm conditions are frequent in season, and you can anchor to the bottom.

An electric outboard of the type that has a submersible motor (most of them) you could extend the leg to put the motor deep in the water. A 10 hp outboard is about 10KW, so you need at least that large a genset for one. I have only a 6 KW genset, but even at half fuel load it will run at max load for about 400 hours.

 

[Benthic2]

I wonder if it would be logistically easier to have a coupling on your drive shaft so you could disconnect it from your main engine and then have a small engine mounted in your engine room with a chain to a sprocket on your existing drive shaft.

It would be really slick if a designer put the generator motor in such a position to be able to serve in this dual purpose. That way there would be very little extra equipment or space required.

 

[diver dave]

An array of trolling motors. Hopefully, some IC engine is still able to charge the dc system. Have lots of food.

 

[rslifkin]

A little quick math on the prop load curve for my boat says that if I strapped a 3kw electric motor to each shaft and ran the pair from my 6.5kw generator, I should be able to turn the shafts at about the same speed as the engines idling in gear or maybe a hair less. In calm water, that would be good for 4 kts or a hair more.

The math makes it look like motors on the existing shafts would work better than I would have expected. Realistically, with twins I'd want a 6kw motor on each shaft (and just throttle them down), that way I'd still have the full 6kw of drive if I lost use of one shaft. Of course, I'd have to lose use of both engines for this to be useful, so I'd skip it on a boat with twins.

If the generator fuel burn is to spec, moving the boat that way would make range a complete non-issue, as I'd only be burning 1 gph for ~6kw, so in flat water, we'd be looking at 4+ nmpg.

 

[BandB]

Epropulsion makes 9.9 HP outboards. I was thinking a pair of those on a 40' boat might push it between 3 and 5 knots. They might also work nicely on a RIB.

If the outboards were manageable to push the boat, I would assume there should be enough diesel to run the generator without running the main engine. Obviously one would need to do some runs to determine fuel consumption over a few days.

Ted

That would be an interesting calculation. We think of generators as using very little fuel per hour. However, we don't think of that in miles per gallon and converting the generator time to the electric outboard time then to nmpg is an interesting equation.

We once did a similar calculation with ribs. Gas ribs would clearly not have the fuel capacity to serve to get one home from sea. So, the question was diesel ribs. Here was the discussion. Take a 130' boat with 5790 hp and at 11 knots it gets about 0.41 nmpg. What about the diesel RIB with 120 hp Yanmar? Let's say it can pull the larger boat at 5 knots. Now normally at 5 knots it would get much better than 0.41 nmpg. Even at 20 knots it would get over 1 nmpg. However, now it's using the hp it would at 20 to only get 5. To add to this you have the generator running to support the boat. Normally on a boat burning 40 to 200 gph depending on speed, generators burning another gallon or two is nothing. However, when you're only going 5 knots then it becomes significant to your fuel usage.

The conclusion was that the 130' boat pulled by the RIB would be less fuel efficient than under it's normal propulsion. However, it also was that the boat had a reserve of fuel at slow speeds like 11 knots and except in the greatest distances would have enough fuel to be towed by the RIB. Now this was mostly bored engineers studying and not really tested. Still seemed workable and RIB could be raised if conditions too bad. Numbers still unknown though were how fast the RIB could tow to get better fuel usage and what would happen to all the numbers based on wind and seas. What if 4'? What about 6'? Another issue was the constant refueling of the RIB. The Diesel RIB's hold 18 to 26 gallons, depending on size. If you're refueling every two hours or so, then that becomes a longer, more tedious trip home.

So where did that leave things? Certainly distance from shore would matter a lot in deciding. However, in most situations might use a RIB to make progress, but would also get another boat on the way to either repair things or to tow safely to shore even if 1000 nm. This would obviously be very expensive and would not be a traditional emergency tow service although a tow like used to move barges could be perfect or a large boat, but fuel capacity and range would be key.

Then it comes to what would disable a boat. Many things might be repaired if parts and expertise available so solution is to helicopter the parts and expert in. Then you talk about those things that couldn't be repaired at sea or where one engine wouldn't still be operable. Now you're into shafts and underwater structure and situations where you've hit something and likely have more damage and if given enough time are at risk of sinking so you must abandon the boat.

The reality is these are interesting theoretical discussions but the likelihood of the exact situation being theorized actually happening is so remote as to render the conclusions unusable. Hopefully, if presented with such an issue at sea, one can come up with a solution. The electric outboards may be possible. Factory installed get-home is the best solution if you have usable fuel and drive. Even the electric solution depends on usable diesel.

My vote is a retractable pod drive driven by the generator. It's within the hull unless needed.

 

[Marco Flamingo]

I admit I didn't read all posts closely. No need. The best solution doesn't attach to the swim step. No pull start. Doesn't require a membership. Works from Nome to Tierra del Fuego and back up the other side to Ivujivik. The size of a brick and weighs only 3 ounces. 3 ounces of crisp $100 bills. You might laugh, but it's way cheaper than some of the options above. And if you don't use it, you get to keep it when you sell the boat. A credit card weighs even less, but doesn't work in all situations.

 

[OldDan1943]

Gosh, I am very happy with my nuclear power plant and steam driven turbines.

I do believe we are all just talking theory and fantasies.

 

[BandB]

I admit I didn't read all posts closely. No need. The best solution doesn't attach to the swim step. No pull start. Doesn't require a membership. Works from Nome to Tierra del Fuego and back up the other side to Ivujivik. The size of a brick and weighs only 3 ounces. 3 ounces of crisp $100 bills. You might laugh, but it's way cheaper than some of the options above. And if you don't use it, you get to keep it when you sell the boat. A credit card weighs even less, but doesn't work in all situations.

3 ounces of $100 bills will not come close to the cost from 500 miles or more. Maybe I spoke too soon. Someone weigh some.

 

[BandB]

3 ounces of $100 bills will not come close to the cost from 500 miles or more. Maybe I spoke too soon. Someone weigh some.

Ok, all bills weigh 1 gram. 1 ounce is just over 28 grams. 3 ounces about 85 grams. So that's 85 bills. 85x100=$8,500. Nope, need to add more to your pack for long distance tow. Sorry 3 ounces doesn't come close.

 

[O C Diver]

I do believe we are all just talking theory and fantasies.

Pretty much.

Came to the conclusion a while back that if I were to take a trip to Bermuda, the simple solution would be a buddy boat. Even if I had to pay some portion of their expenses, it would probably be inexpensive with essentially total redundancy.

Ted

 

[diver dave]

Gosh, I am very happy with my nuclear power plant and steam driven turbines.

I do believe we are all just talking theory and fantasies.

And yes, even those have needed help getting home.

 

[BandB]

Pretty much.

Came to the conclusion a while back that if I were to take a trip to Bermuda, the simple solution would be a buddy boat. Even if I had to pay some portion of their expenses, it would probably be inexpensive with essentially total redundancy.

Ted

If not that, at least someone else you know who could and would come help you.

We do similarly even on trips to the Bahamas in that we always make each other aware and have someone on land with access to a boat that they could quickly come to us if we had a disabling problem and if tow services were not responding. Not worried, once in the Bahamas, but being disable in the gulf stream is what we are considering.

We have a small group that always has access to each other's cruising plans. Worst situation is the missing persons on missing boats that no one knew where they were headed. Difficult enough to do a search when you know, but searching the world over is impossible.

 

[OldDan1943]

Pretty much.

Came to the conclusion a while back that if I were to take a trip to Bermuda, the simple solution would be a buddy boat. Even if I had to pay some portion of their expenses, it would probably be inexpensive with essentially total redundancy.

Ted

and sell out boats at a tidy profit too.
Hmmmm, go back to the states or Canada, prepare 2 boats, repeat the trip.
How many boats do you think we could sell in Bermuda before they caught on?

 

[Swa]

I've been 1000 miles plus offshore many times without much thought when I was in the Navy. I really can't imagine finding any pleasure cruising 3-500 miles away from help. If I were to find myself in a situation as mentioned. I would eventually wake up and realize it was just a nightmare. Regardless, You guys are great. I enjoyed reading your posts. This forum is a great resource of information. My vote would be to tow along another boat. Maybe hang the diesel OB on it

 

[rpackard]

electric get home motor

My Willard 40 has a 7.5hp AC electric motor that can be coupled to the prop shaft and powered off the generator. This delivers a speed in flat water of about 4k. Of course this will only help if it is the main engine that is down. It uses the same prop and fuel supply. An on board frequency controller permits variation in speed and direction. Fortunately never had to use it.
Richard P

 

[OldDan1943]

My Willard 40 has a 7.5hp AC electric motor that can be coupled to the prop shaft and powered off the generator. This delivers a speed in flat water of about 4k. Of course this will only help if it is the main engine that is down. It uses the same prop and fuel supply. An on board frequency controller permits variation in speed and direction. Fortunately never had to use it.
Richard P

Sure would be interesting to see how it performs. Maybe you can check it out???

 

[DDW]

My vote is a retractable pod drive driven by the generator. It's within the hull unless needed.

A good description of an electric outboard.

I admit I didn't read all posts closely. No need. The best solution doesn't attach to the swim step. No pull start. Doesn't require a membership. Works from Nome to Tierra del Fuego and back up the other side to Ivujivik. The size of a brick and weighs only 3 ounces. 3 ounces of crisp $100 bills. You might laugh, but it's way cheaper than some of the options above. And if you don't use it, you get to keep it when you sell the boat. A credit card weighs even less, but doesn't work in all situations.

Not sure where you have cruised, but there are places where tows simply are not available. Sure for enough money anything is available. But could be many times more than your boat and bank account are worth. Try calling TowBoatUS from Nome and see how quick they respond.

The problem with any scheme that powers the main shaft is it assumes the main shaft and propeller are functioning. That might actually be the thing that is wrecked (particularly in the PNW with all the lumber in the water). Makes more sense on twins, because it would be unlikely that both props would be wrecked - but then on a twin, you already have redundancy so why bother?