Get Me Home Power

manyboats said:

There is a good article in an old PMM.

A 34' Mainship w twin engines and a single shaft (as I recall) was the subject of the project. Diesel electric bus components were used. Worked very well. But probably wasn't very economical to purchase and install. The project was aimed at re-powering.

Must have been some significant downside as I've not heard of it since.

Click to expand...

It was the other way around. One engine and two shafts.

Think about it, shafts and gearboxes are cheaper than engines and one engine uses less fuel that two.

Bill-your one vs two theory does not pan out in practice. It takes the same energy to move a mass through the water whether that energy cones from one engine or two. A large single does in fact use slightly less fuel then smaller twins, but the difference is really negligible.

Capt.Bill11 said:

It was the other way around. One engine and two shafts.

Think about it, shafts and gearboxes are cheaper than engines and one engine uses less fuel that two.

Click to expand...

Like the boat across from us a few years back, a Geared Up conversion.

THD said:

Bill-your one vs two theory does not pan out in practice. It takes the same energy to move a mass through the water whether that energy cones from one engine or two. A large single does in fact use slightly less fuel then smaller twins, but the difference is really negligible.

Click to expand...

It's not my theory. I'm just reporting what some one actually did. Take it up with them.

[FONT=Verdana, Arial, Helvetica][FONT=Verdana, Arial, Helvetica]http://tinyurl.com/n6sx395

Boating - Google Books
[/FONT][/FONT]


Boater's Resources: Boating, marinas, accessories, equipment, and supplies at discounts you’ll love!

These are the reported fuel use figures:

"@15mph, 1+1 gives 1.84mpg, 2+2 gives 1.49mpg, 1+2 gives 2.06mpg

@ 21mph, 1+1 gives 1.7mpg, 2+2 gives 1.4mpg, 1+2 gives 1.95mpg

@ 26mph, 1+1 not tested, 2+2 gives 1.17mpg, 1+2 gives 1.79mpg"

1+1 is 1 eng 1 shaft
2+2 is 2 eng 2 shafts
1+2 is 1 eng 2 shafts


From the old web site:

"
[FONT=Verdana, Arial, Helvetica][FONT=Verdana, Arial, Helvetica]With over 25 years of production experience in corrosion resistant gear drive systems for the automotive, off-road, and industrial applications, Geared Up Systems now provides the ultimate drive system for the marine industry, the single engine twinscrew drive.

Let Geared Up Systems assist you in laying out the optimum system for your boats. The drive system offers many benefits including maneuverability, economy, installation ease and design versatility. Without changing your design, you could be offering your customers new options with these advantages:
Maneuverability: Independent port and starboard transmissions allow maneuverability previously found in twin engine boats only. Holding up on a fishing spot, parking or docking (even in a river or tidal current!), and positioning or repositioning a workboat can be accomplished as easily as with a twin screw, without the need for bow thrusters.
Economics: The drive system provides single engine economies, including the savings in fuel, servicing, and layup, plus the savings of the cost of the redundant engine, and the economics of pushing a boat that weighs less and needs to carry less fuel for the same mission capability.
Better Boat: The system allows the engine to be buried deep in the hull of the boat, lowering the center of gravity. A shallower draft provided by twin propellers, spread-out rather than under the keel. Whether your boat needs the engine forward or astern, or if you need an off-center line engine installation, the System makes it possible.
Ease of Installation: In all installations, the engine, engine adapter and primary splitter gearbox mount as a single unit. The final drive gearboxes and/or marine transmission mount in alignment with the propeller shaft. The splitter gearbox and the final drive gearboxes are connected with the constant velocity shafts or universals allowing for engine torque within the mount and misalignment between the primary and final drives. Propeller thrust may be terminated into the final drive component or a thrust plate arrangement that terminates into the boats stringer system."


[/FONT][/FONT]

Very good dudes,
Yes you are right Bill. But I could'nt find that one. I did fine another in the June 03 PMM. Page 140 for those that have old PMM. Presented by a company called "Fast/Siemens" system and it's actually diesel electric. Two Cat 3208 engines were replaced w a Cummins B220. If it was available and I had plenty of money I'd be very interested. With this system a genset would be required for the traditional get home.

Singles are often more efficient that singles because they have bigger engines frequently turbocharged. If you made everything equal (or very close) the twin could be more efficient because of the counter rotating props.

To have a fair comparison you'd need all the engines having equal specific fuel consumption per hp hour. Twin keels on the twin ect ect.

But whatever the difference THD says "the difference is really negligible. And I fully agree.

But fuel consumption isn't feared here w all the twin Lehmans in residence. But no one can argue that twin engines is'nt a supreme "get home" setup.

Two engines equal twice the maintenance/failure over one, especially when they are all equal horsepower.

Don't you guys have Volunteer Marine Rescue or anyone like that, that can tow you back to port?


Sent from my iPhone 5S using Trawler Forum

Hendo78 said:

Don't you guys have Volunteer Marine Rescue or anyone like that, that can tow you back to port?


Sent from my iPhone 5S using Trawler Forum

Click to expand...

Within Canada and the United States there are commercial tow operations that will tow you back to port. Annual membership in one of the two large competitors is economical. Outside of this portion or North America, for example Central America and the Caribbean, organized tow assistance varies by the location and in many cases is non-existent.

As I look to move from gas modified v boats to a trawler I've settled on the following:

Fiberglass hull, Semi or full displacement, No Teak Decks, Two Staterooms, Stall Shower, near stand up engine room, Queen walk around bed AND twin engines.

Yes I've seen all the pros and cons for sometime, but after following the blogs of liveaboards with one motor and those of twins and the fact that the boat I will be will be nearly 30 years old and I could be anywhere in the Caribbean I will have twins. The pros and cons are all true and each of us need to find our own compromise. I am not going to rely on rescue from the coast guard from some of those island countries and Boat US is only good to Bimini.

ghost said:

While I'm not quite sure the marine recreational industry is ready yet, i believe that diesel electric setups will eventually be the answer here.

1.) You can generate charge from any number of diesel engines. Singular or in combination. (Main1, Main2, Generator).

2.) You can send that electrical current wherever you want/need it. (Prop 1, Prop 2, Inverter, Batteries)

3.) If one prop/motor fails, you don't lose the redundancy of the engine itself, just because its drive train is hosed.

It seems like a combination that would offer the most redundancy in case of failures. If you wind up with bad fuel, that could still impact all engines, but you only need to get filters changed on one engine before you can run both/all props/thrusters.

Electric motors of this size have been around for a long time, but have come a long way just in recent memory in being ideal for these kinds of systems.

If I could have a single diesel and a moderate size generator, with twin screw driven by independent electric motors, I think that combination would have some real advantages.

Click to expand...

One of the big downsides to Diesel electric is moisture. The plant needs heat at all time . If you aren't running the engine or gen set , then you need shore power for heat.....lots of heat to resist corrosion.
One of my ex-employers found this out the hard way. Electric bill for shore power for this DE was 4-6 thousand dollars monthly. On its own meter.

Having a plan B is always a good idea; a plan C and D might even be advisable.

My plan A is a 36hp single diesel.
Plan B is 300 square feet of sail.
Plan C is the 3hp dink outboard on the swim platform
Plan D is the local Volunteer Rescue service.

So far I've only had to use A & B.

Adding a mast isn't usually cost effective for most trawler type boats; but I would still consider it before any type of stern drive.

Originally Posted by kraftee
...at boat shows, people would occasionally ask if we would build our Great Harbours with single engines (we actually did build ONE that way.) If they seemed to have even the least bit of a sense of humor, I would tell them, "Yes, but it would be installed off-center in the engine room - oh, and for no-extra charge, we'll include a wing engine just like it on the other side."
You jest, Eric, but don't think that I haven't imagined an N-37 with a port side main (84 HP) with a larger rudder, and leave the 56 HP standard starboard. From what I recall, you can nearly get hull speed out of one 56 HP, yes? I can see you laughing and shaking your head at why people don't leave a good thing be. But you have to admit,....there are no sub-100 hp diesel twin trawlers that I can think of made in the last 20 years around here, unless you include catamarans. Do you have many owners that run on one engine.....switching to the other and back again, etc.. How do the 37's perform on one engine?
__________________
Larry

Click to expand...

Larry, yes, I was jesting a bit there. I am NOT going into the whole twins versus single argument. It's kinda like trying to change someone's political or religious beliefs. You can spout your "facts" all you want, but people are gonna believe what they believe. That being said, I will answer your questions.

We have done some testing and determined that the fuel savings of running just one engine are pretty negligible. It takes a given amount of fuel to produce the required horsepower to push a given hull through the water at an identical speed - whether you are using one engine or both. The difference being a complicated formula comparing the drag of the "dead" prop (whether tied or free-spinning) to the additional friction losses created by the other running engine.

In the real world, on our boats at least, you get about a 10-degree yaw when running on one engine (not difficult to deal with - the autopilot handles it just fine) and lose about a knot of speed at normal cruise rpm. Fuel savings are, as I said, negligible if you compare that to simply slowing both engines down that extra knot. You are correct though that the boats will ALMOST achieve hull speed on one engine

We have had owners safely and comfortably bring their boats back from the Bahamas on a single engine due to some kind of failure or problem. The best "running on one" story I have heard concerns "Ho-Okele", the N37 that we delivered to Hawaii on its own bottom (and the only Great Harbour with Luggers.) On an 800-mile trip back to Hawaii from the Johnston Atoll, the original owner told me that he had a hydraulic failure on one of his Luggers in very large seas. I asked him how things worked out. He said it was no problem at all, he just trucked on home on his "spare" motor! Intrepid guy.

Does anyone think some folks are getting a little carried away here? Spare starters? Diesel electric? Chain drives and extra engines? Masts and sails (on a powerboat)?

Carried away

I don't know, but I've been stranded and it sucks and at the end of the day it depends on comfort level and resources. Trawler Beach House lost a couple of weeks chasing down one little housing that was cracked and spewed oil all over his engine room 3 times on his 30+ year lehman. If he'd been on Long Island Bahamas, It could have been ugly. Lots of neat ideas. Many Trawlers have a stabilizing sail that could help. I'm liking the extra expense of a second motor for my family.

Wzdr02 said:

I don't know, but I've been stranded and it sucks and at the end of the day it depends on comfort level and resources. Trawler Beach House lost a couple of weeks chasing down one little housing that was cracked and spewed oil all over his engine room 3 times on his 30+ year lehman. If he'd been on Long Island Bahamas, It could have been ugly. Lots of neat ideas. Many Trawlers have a stabilizing sail that could help. I'm liking the extra expense of a second motor for my family.

Click to expand...

For most of us, a towing policy at $150 per year takes care of it.

Now if you will not have this available, perhaps having a 30 year old engine is taking a risk. A new or nearly new engine that's been well maintained would lessen the risk and having one that's still in production with wide parts availability would also help. I think there's a practical limit to the spare parts you can carry on board. Filters, belts, impellers, yes, starters alternators add a lot of expense and weight and are generally reliable. You also have to have the tools and knowledge to replace these parts.

Twins can still leave you stranded if they share the same fuel source and even with dedicated fuel sources, if you fill both tanks from the same source you can be dead in the water.

In the end it's where you travel, the risk factor and your comfort level. These are different for each boater.

rwidman said:

Does anyone think some folks are getting a little carried away here? Spare starters? Diesel electric? Chain drives and extra engines? Masts and sails (on a powerboat)?

Click to expand...

Ron
There are so many different situations people are in that what is reasonable depends on the situation. In Charleston I can get towed back to port and probably have a replacement starter delivered the next day or certainly the following day. In Central America or the islands of the Eastern Caribbean it may take a couple of weeks or more to get spares. As far as towing goes, there are so few power boats that you would likely need to get a tow from a sailboat.

As I have found out, air shipping to the Eastern Caribbean, the customs broker, local taxes and local delivery usually cost more than the part.

Towing

Marty and Ron all good points. I have always had towing from Boat US. Wouldn't leave the dock without it and I'll certainly have a fuel polisher and Bug Out. Things can and will go wrong. But towing policies don't cover most of the Caribbean. I'd prefer and am seeking a boat with CAT diesels like 3208.

Spare starters? Always a good idea BUT,

If someone is contemplating a spare most anything the drill is to do what offshore sailors do.

Install the spare , place the operating unit in a vacuum bag and carry that!

speaking of the spares list vs the get home/twin engine...

I like the spares idea for a ocean voyaging single.. on the Nordhavn I spend a lot of time on she has a very comprehensive list of spares.. but it doesn't include a spare engine computer. During a particularly close and violent electrical storm I started to wonder how the new electronic controlled engines fair in a lightening hit... anybody have any idea?

The above mentioned N57 also has a get home.. it has seen some use between Alaska and New York.

HOLLYWOOD

manyboats said:

But whatever the difference THD says "the difference is really negligible. And I fully agree.

Click to expand...

I don't know, for the Geared Up system at least, IF these figures are correct:

@ 21mph,
1+1 gives 1.7mpg or 100 gal=170 miles
2+2 gives 1.4mpg or 100 gal=140 miles
1+2 gives 1.95mpg or 100 gal=195 miles

that is a significant difference I'm mileage.

But the point might be moot anyway. Does anybody know if the Geared Up system is even available any more?

But then a 30 more miles per 100 gallons difference between the 1+1 and the 2+2 configurations is nothing to sneeze at either.

rwidman said:

Does anyone think some folks are getting a little carried away here? Spare starters?

Click to expand...

No. Spares like starters are no big deal to carry and store. Not every one does their boating where help is just a phone or radio call plus a CC away.

Capt.Bill11 said:

No. Spares like starters are no big deal to carry and store. Not every one does their boating where help is just a phone or radio call plus a CC away.

And from Fast Fred - Install the spare , place the operating unit in a vacuum bag and carry that!

Click to expand...

+1 Capt.Bill11 and FF

And . . . IMHO, the "tools and knowledge to replace these parts" is fundamental to operating a 'motor vessel' although some may disagree.

hollywood8118 said:

I like the spares idea for a ocean voyaging single.. on the Nordhavn I spend a lot of time on she has a very comprehensive list of spares.. but it doesn't include a spare engine computer. During a particularly close and violent electrical storm I started to wonder how the new electronic controlled engines fair in a lightening hit... anybody have any idea?



HOLLYWOOD

Click to expand...

Not well in some cases. I was hit twice in a row in the San Blas islands in Panama at on the anchor chain where it went into the water and luckily all I had to do was turn the engines off and the MTU displays resent and there was no damage to the electronic controls. Nor to the rest of the electronics.

On the other hand a friend of mine runs an 86' Lazarra up in Panama City FL and he got hit by lightening a couple of weeks ago and it totally F-d up the engine electronics to the tune of many thousands of dollars. And that is not even counting all the other stuff on board that got fried.

hollywood8118 said:

speaking of the spares list vs the get home/twin engine...

During a particularly close and violent electrical storm I started to wonder how the new electronic controlled engines fair in a lightening hit... anybody have any idea?

Click to expand...

The little peashooter Yanmars in our Great Harbours are, of course, not electronically controlled. However, in June of 2012, I brought our charter in and tied up Spoonbill at Treasure Cay during a horrendous thunderstorm. About an hour after the storm they towed in a big, new Catana catamaran that had been struck by lightning. Fried all of the nav electronics AND the electronics for the engines. Neither engine could be started.

kingfish said:

Looking at a single screw vessel and doing research on get home.

Kingfish
New Orleans

Click to expand...

Get home from where? How big a boat you looking at? Need more data!

I like the idea of a spare and think Ted and Sarah have the ideal solution for their single screw 36' Manatee.

Article here: Janice142 article Manatee Moves

Frankly, I'm looking at a way to mount an outboard astern of Seaweed so I won't have to call TowBoatUS ever. I do so admire the genius that figured out how to make a universal joint work for this application. No matter the seas, the boats work together.

Anyway, take a look and see if you could adapt it for your boat. I cannot (swim platform) but an outboard bracket like what the sailboats have that comes off the transom just might be the ticket. I'm semi-actively searching for the bracket. Once I find that then I'll be half-way to a solution to dual power.

Wish me luck!

hollywood8118 said:

speaking of the spares list vs the get home/twin engine...

I like the spares idea for a ocean voyaging single.. on the Nordhavn I spend a lot of time on she has a very comprehensive list of spares.. but it doesn't include a spare engine computer. During a particularly close and violent electrical storm I started to wonder how the new electronic controlled engines fair in a lightening hit... anybody have any idea?
...
HOLLYWOOD

Click to expand...

I talked with some JD representatives and took their engine class at Trawler Fest last may. I specifically asked them about what happens if lightning hit the boat and took out the engine computer. Would I be able to run the engine.

The answer was no.

I suspect this will be true on any engine meeting Tier III maybe Tier II pollution standards. From my reading, and I hope correct understanding of the EPA regulations, marine engines for the boat size we want, will be exempt from Tier IV, or we would have more issues because of DEF.

The other interesting point they had in class was about power. An engine needs air, oil and fuel to run. But the new engines need power. Power is a consumable like fuel. If you do not have power, the engine is not going to run. This is not about starting the engine which usually requires power but the actual running of the newer engines. This is unlike the older engines that would run as long as they had fuel and air. Now, power is needed along with fuel and air.

Later,
Dan

dannc said:

I

The other interesting point they had in class was about power. An engine needs air, oil and fuel to run. But the new engines need power. Power is a consumable like fuel. If you do not have power, the engine is not going to run. This is not about starting the engine which usually requires power but the actual running of the newer engines. This is unlike the older engines that would run as long as they had fuel and air. Now, power is needed along with fuel and air.

Later,
Dan

Click to expand...

I am thankful for my Lehman 135. Of course Bay Pelican might not exist if it had an electronic engine. Under a prior owner, lightening wiped out everything while the boat was underway. However, the engine continued to run and the boat made it back to port.

You can have ninety nine spare parts on your boat and still be missing the part you need to fix a problem. Like the man said, the engine computer. Do you carry a spare engine computer?

Capt Bill-I saw your post re the fuel use estimates. Since I know nothing about the tests performed or how they were performed, I can't comment on them. That said, I have seen other comparison tests run and have talked to several engineers over the years and there seems to be pretty much consensus that the 1 vs 2 fuel savings are marginal at best. As was noted, the same energy is needed to produce the same result.

As to the single v twin debate, even though we have twins (JD 6068 TFMs), it is a personal preference of mine. The reliability of continuous-duty rated modern diesels is pretty amazing. I don't think I know anyone who has had a diesel failure caused by internal engine issues. The vast majority of diesel problems are ancillary items. As has been stated here many times, 90% of diesel issues revolve around fuel systems, i.e. fuel itself, filters, pumps. Cooling/water problems probably come next. The vast majority of these types of issues are fairly easily resolved with a bit of knowledge and an adequate supply of spares.

I have never thought about lightning as we don't have much in the PNW. Now you guys have given me a whole new thing to worry about!