Single vs Twin: It's Baaaaack!

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psneeld said:
mahal said:
Those of us that have singles, carry spares, know how to deal with failures and emergencies in a timely way have ecxactly the same opportunities....continue the trip or go home.:D:thumb:
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I would rather do the repairing at my destination or homeport rather than at sea. And although I can rebuild a Lehmans, as most can as it is a very simple engine, at homeport I have the option to hire someone to do the fixing in case I don't feel up to it.
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So would I but usually in a few moments depending on the failure...you are going again...

And manyboats...bailing wire and confidence is not what it takes to keep going...it takes proper spare, tools and knowhow....

I don't disagree with the luxury of 2 engine thinking...but it seems that while single owners fear being left stranded...they seem to fear it less than twin owners...thus the reason WHY they are twin owners and single guys just grin and bear it...
 
SeaHorse II said:
I had a 38' sport fisher with a pair of Cummins 210s and 2 single engine boats, both with Cummins. I've also had a 54' sport fisher with a pair of 8V92 DDECS. (760hp each) My current boat is a single & has a Cummins 330B. Now, I don't want to throw mud on anyone else's engines but I've had Cats (2 pairs of 3208s) a pair of Perkins 200s and 3 Cummins & I love the Cummins. Easy to change the belts, you can move the dip stick and oil fill if it's not in a place that suits you, etc. I've never had a problem or engine failure with the Cummins. :banghead: They would be great re-mans for a lot of boats.
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I would agree, I put a pair of Reman 330's in my boat in 2011.
 
Sorry psneeld the bailing wire reference was attempted humor.

And yes I've got so many spares I'd need to anchor up for awhile to find them. Lucky I have a wife that is an organizer.
 
psneeld said:
....but it seems that while single owners fear being left stranded...they seem to fear it less than twin owners...thus the reason WHY they are twin owners and single guys just grin and bear it...
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I've flown single engine airplanes for forty years. The GB we chartered before buying the one we have now was single engine. The narrowboats we've run in England are all single engine. All the vehicles I drive are single engine.

But engine failure has never been anything I've spent any time worrying about. And while we have had to shut an engine down on our boat on three occasions (and once when I caused one to shut down during a fuel transfer) and the fact that we were able to continue the run with no fuss or delay was nice, engine failure or shutdown is not the main reason I prefer a boat with two (or three) engines.

I simply like running and manipulating engines and transmissions. I find it much more interesting and challenging than running a single engine boat.

While there are some really nice boats out there with single engines, particularly lobsterboats, I would not be interested in owning one because I don't want to go back to running just one engine. Compared to operating two I would find it less enjoyable and less satisfying.

Back in the mid 1980s I had an opportunity to do some filming on a supply boat serving the offshore oil rigs off southern California. The boat I was on had three engines. And even though at the time I was not into the kind of boating we're into now, I found the manipulation of those three engines fascinating to watch and learn about. The skipper of that boat was an artist with the throttles and shifters as he held the boat in exact position under the rig's crane in the big swells while they offloaded equipment and people. I'd love to try it someday.
 
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Having owned a bareboat charter company for 7 years, dispatching over 1200 charter weeks, I can say that I much prefer a single engine boat to a twin. We only had one engine failure where the charter couldn't continue and that was a brand new Bayliner 47 that had a fuel injection pump fail.

As far as prop/rudder damage, the singles were better hands down. We had about 20 incidents in the 7 years where a prop, propshaft, and/or rudder where damaged and the score was:

Twin engine: 20
Single engine: 0

This is not opinion.....this is fact.

When we designed our trawler line, most were designed as single engine with the ability to build them as twins if the client desired. We made this decision because of our personal experience as well as that of our designer and production manager. Steve Seaton (designer) prefers singles. Most true long range trawlers are singles. To my knowledge, Nordhavn has had little if any engine failures. Salvation II, a Nordhavn 46 circumnavigated in the 90's, had 9600 hours on the engine when the Sinks sold the boat and they never used their wing engine except for once or twice to make sure it would run.

Our former production manager runs a fleet of 8 fish boats in the Bering Sea....all singles.... In fact, he could not think of any of the boats that he fishes with that are twins. And these guys not only rely on their boats for their livelyhood, but for their very lives.

A properly maintained single engine boat is reliable, more efficient, and less prone to damage by striking something. Most problems encountered are fuel related or are caused by overheating due to a failed pump (impeller usually) or a clogged strainer. Anyone not able to deal with these issues should not be out boating in remote areas where they can't radio for assistance.
 
OkSkipper said:
... We had about 20 incidents in the 7 years where a prop, propshaft, and/or rudder where damaged and the score was:

Twin engine: 20
Single engine: 0
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Based on my observation of a lot of bareboat charter customers over the years, those statistics could say a lot more about the nature of charter boat customers than it does about how many engines are in a boat.

The motto in the film industry is "Trash the rental." Interpreted into the boat world, "Not my boat, not my problem." :)
 
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Marin said:
I simply like running and manipulating engines and transmissions. I find it much more interesting and challenging than running a single engine boat..
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Marin, I understand your passion.

Nevertheless, I'm a single-function kind of guy. (Walking and not chewing gum at the same time.) :ermm:
 
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Originally Posted by Marin
"I simply like running and manipulating engines and transmissions. I find it much more interesting and challenging than running a single engine boat.."

Surely a dichotomy here Marin? You enjoy using the boat's multiple engines and transmissions, yet it is that very time you spend behind the wheel getting to your destination that drives you crazy, the old Lehman's slowness nearly kills you.... '8 knots, give me a break!'

However, the quicker you get to your destination, the less time you have for the enjoyment and challenge of those twins. So if you had to chose between speed or twins which would it be. Could you sell your soul for a single capable of say 30 knots? :whistling:
 
Marin said:
I've flown single engine airplanes for forty years. The GB we chartered before buying the one we have now was single engine. The narrowboats we've run in England are all single engine. All the vehicles I drive are single engine.

But engine failure has never been anything I've spent any time worrying about. And while we have had to shut an engine down on our boat on three occasions (and once when I caused one to shut down during a fuel transfer) and the fact that we were able to continue the run with no fuss or delay was nice, engine failure or shutdown is not the main reason I prefer a boat with two (or three) engines.

I simply like running and manipulating engines and transmissions. I find it much more interesting and challenging than running a single engine boat.

While there are some really nice boats out there with single engines, particularly lobsterboats, I would not be interested in owning one because I don't want to go back to running just one engine. Compared to operating two I would find it less enjoyable and less satisfying.

Back in the mid 1980s I had an opportunity to do some filming on a supply boat serving the offshore oil rigs off southern California. The boat I was on had three engines. And even though at the time I was not into the kind of boating we're into now, I found the manipulation of those three engines fascinating to watch and learn about. The skipper of that boat was an artist with the throttles and shifters as he held the boat in exact position under the rig's crane in the big swells while they offloaded equipment and people. I'd love to try it someday.
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Here's my last sentence on page 3 post 46...:thumb:

"Marin has about the only answer I really accept...he likes driving a twin and that can't be argued with..:D"

I know what you mean...last time I resupplied an offshore jack-up barge I had to do it with a single in big swells...uuuuggghhhh!!!!!!
 
Twin headaches

You will have more days away from the dock with a single then twins. With twins you have twice trouble of keeping them running. Most failure are on start ups not so much running down the bay. I have owned both and I love only maintaining one main engine.
 
OkSkipper said:
A properly maintained single engine boat is reliable, more efficient, and less prone to damage by striking something. Most problems encountered are fuel related or are caused by overheating due to a failed pump (impeller usually) or a clogged strainer. Anyone not able to deal with these issues should not be out boating in remote areas where they can't radio for assistance.
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Although I can certainly buy in to the advantages of twins on a cruising boat, I still remember what my instructor told me when I was pursuing my multi-engine rating. I always thought I'd be much safer in a twin engine plane than flying a single. He pointed out that you have twice the problems, twice the maintenance, more fuel consumption and longer landing strips in a multi engine plane than you do with a single. Having owned both types, I really enjoyed the simplicity of the single engine plane. (Not to mention the increased PM that I employed to assure that the engine was in the best condition.)

You can paint a pretty good scenario for either the twin or single engine boat. The fact of the matter is, that with an engine failure, you can still limp home in a twin. :hide:
 
SeaHorse II said:
Although I can certainly buy in to the advantages of twins on a cruising boat, I still remember what my instructor told me when I was pursuing my multi-engine rating. I always thought I'd be much safer in a twin engine plane than flying a single. He pointed out that you have twice the problems, twice the maintenance, more fuel consumption and longer landing strips in a multi engine plane than you do with a single. Having owned both types, I really enjoyed the simplicity of the single engine plane. (Not to mention the increased PM that I employed to assure that the engine was in the best condition.)

You can paint a pretty good scenario for either the twin or single engine boat. The fact of the matter is, that with an engine failure, you can still limp home in a twin. :hide:
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Can't speak for anyone else but many are agreeing with me...engine FAILURES are rare on either twins or singles...

Component failures for the handy are rarely even reason to anchor...most things I can change out in minutes or live without until I can moor safely...usually at the place I wanted to spend the night anyway.

Most of us agree that engines are so reliable no with decent maintenance..why are so many worried to begin with???

Single OR twin...:confused:
 
psneeld said:
..why are so many worried to begin with???
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What's the point in owning a boat unless you can find something to worry about?

If we removed every thread that could be defined as based on worry about something, the site would be empty.
 
"A properly maintained single engine boat is reliable"

Can't argue with that one but wouldn't two of those properly maintained single engines be twice as reliable? There had to be a good reason why Nordhavn required their NAR participants to have a secondary means of propulsion.

My twin engine boat is very reliable but not as reliable as one with three engines.
 
mahal said:
"A properly maintained single engine boat is reliable"

Can't argue with that one but wouldn't two of those properly maintained single engines be twice as reliable? There had to be a good reason why Nordhavn required their NAR participants to have a secondary means of propulsion.

My twin engine boat is very reliable but not as reliable as one with three engines.
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Can't argue with that logic....unless you really understand logic and then the thought process goes like this...

If something is already nearing 100 percent reliable...then doubling that reliability gets you no return on your investment so to speak. The concept of hull speed is the same...when you need to double the hp just to get a fractional increase in speed...that's where you are.

If I'm not mistaken..didn't the Lunar Module only have one engine? (well technically one descent/one ascent ;)...but only one at a time was useable):socool:
 
psneeld said:
Can't argue with that logic....unless you really understand logic and then the thought process goes like this...

If something is already nearing 100 percent reliable...then doubling that reliability gets you no return on your investment so to speak. The concept of hull speed is the same...when you need to double the hp just to get a fractional increase in speed...that's where you are.

If I'm not mistaken..didn't the Lunar Module only have one engine? (well technically one descent/one ascent ;)...but only one at a time was useable):socool:
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Twin engines are 100% more reliable than singles. 3 engines are 200% more reliable than 1 engine but only 50% more reliable than twins.

To me, I get my return on investment, so to speak.
 
Andy G said:
So if you had to chose between speed or twins which would it be. Could you sell your soul for a single capable of say 30 knots? :whistling:
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Not only no but hell no. We will never own a single engine boat. The only way to go is a twin engine boat that goes fast. Or preferably a triple engine boat.:)
 

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Peter Whiting said:

"When we designed our trawler line, most were designed as single engine with the ability to build them as twins if the client desired. We made this decision because of our personal experience as well as that of our designer and production manager. Steve Seaton (designer) prefers singles. Most true long range trawlers are singles. To my knowledge, Nordhavn has had little if any engine failures."

Good points Peter. On Nordhavns the wing engine is an option. On a price sheet in front of me it is about $45K. Virtually all (maybe 100% even) of Nordhavns built during the past 15 years or so have a wing engine. Certainly resale is a motivator here too. Many have the wing engine installed with a redundant hydraulic pump for thrusters, stabilizers and windlass. Like a seat belt in a car or airplane, the wing engine is there for a hopefully infrequent happening.

But singles do indeed go down. In the past year alone I know of three instances where high end trawlers were towed in due to a grounding, debris in fuel line and failure of shaft coupling.

In Petersburg and Juneau this past summer I talked to several commercial fishing boats who were stuck at the dock for a few days as they sorted out main hydraulic pump issues - the hang ons again. All in a days work they said. The commercial guys are a lot savvier on in the field engine repairs than most of us toy boaters with keeping their singles running - it can be a do or die situation.
 
mahal said:
Twin engines are 100% more reliable than singles. 3 engines are 200% more reliable than 1 engine but only 50% more reliable than twins.

To me, I get my return on investment, so to speak.
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Maybe your talking engines...I'm talking vessel...if a vessels single engine is 100 percent reliable...adding another engine gets you nothing...

I know that's hard to understand...but give it a try...:D
 
Are there no Reliability Engineers on the forum that can reduce this argument to actual statistics? Or even the proper methodology for determining the MTBF difference for single vs. redundant systems?

Then we can then argue about! :D
 
psneeld said:
Maybe your talking engines...I'm talking vessel...if a vessels single engine is 100 percent reliable...adding another engine gets you nothing...
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True, but that's assuming a vessel's engine is 100% reliable 100% of the time. Based on the experience I and probably most of us have had with engines over the years--- inboard and outboard boats, airplanes, vehicles, bulldozers, you name it--- that's not an assumption I'm prepared to make.

While I have never experienced an in-flight failure or shut down with the engines in the single-engine planes I've flown, that's not the same thing as saying these engines were 100% reliable. Most if not all of them exhibited problems at one time or another, including a couple of times when I was operating them.

Most of the time the problems I learned or heard about, or in a couple of instances experienced, did not develop to the point of causing an actual failure or shut down. But most of them were sufficient to cause the plane to be taken out of service so the problem could be found and fixed, or in some cases so the engine could be overhauled.

So given that engines tend not to be 100% reliable 100% of the time, I think Mahal's statement stands.
 
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psneeld said:
Maybe your talking engines...I'm talking vessel...if a vessels single engine is 100 percent reliable...adding another engine gets you nothing...

I know that's hard to understand...but give it a try...:D
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I understand just fine and yes you are correct that if a vessel's single engine is 100% reliable adding another will get you nothing. But until someone invents a 100% reliable engine which will probably never happen (too much of a fantasy), I will only consider boats with twins or a single with a wing engine.
 
Blue Heron said:
Horse is beyond dead.
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I guess....while NO vessel is a 100 percent reliable...I guess 99.9 percent isn't good enough for some. They want a second engine for that 0.1 percent of the time an engine stops working and isn't quickly repairable or can be ignored...because that's MY experience with Marine and aircraft engines in 2 separate marine and aviation careers and a lifetime of boating...

I still go back to one of my first posts...who cares single/twin except like Marin said...he just likes messin' with 2...just like the saying that states "people just like messin' around in boats period!":D
 
Last October I delivered a Bertram 36 SF with very low houred Cummins power and smartcraft electronic controls. The trip was from Southport N.C to Vero Beach. 1 day steaming outside in good wx and 2 days in the ICW. Day 2 both engines dropped from high cruising speed to idle and both came out of gear (loss of propulsion). After several minutes of inspection, both went back into gear and we were on our way. This situation repeated itself several times, with the last time being in Jacksonville where the ICW crosses the St Johns river.
The culprit turned out to be the mother board for the electronic controls. No way to put engines in gear and idle home due to electronic controlled valves on the ZF gear box.
A week lost while board was sent out.
The new owner, an experienced attorney but new to boating was less than happy with his new (2008) boat. For me it was an inconvenience since I live in Jacksonville.
I will take simple cable controls that can be put in gear to at least get to a dock. The single vs twin would put both camps SOL on this one.
 
Marin;123499While I have never experienced an in-flight failure or shut down with the engines in the single-engine planes I've flown...[/QUOTE said:
I flew for a living in the Navy and have had MANY routine shut-downs (and loiters) and several emergency shut downs as well. The inability to shut down those engines would have put us at much greater risk (over-speed, compressor failure, rotor burst, catastrophic failure). I never had to ride one into the water for that very reason.

This is the primary reason the US Navy has migrated to multi-engine aircraft over the years. The stakes aren't as high in boats, but I'd still rather limp home on one if something was hinky.
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SomeSailor said:
I flew for a living in the Navy and have had MANY routine shut-downs (and loiters) and several emergency shut downs as well. The inability to shut down those engines would have put us at much greater risk (over-speed, compressor failure, rotor burst, catastrophic failure). I never had to ride one into the water for that very reason.

This is the primary reason the US Navy has migrated to multi-engine aircraft over the years. The stakes aren't as high in boats, but I'd still rather limp home on one if something was hinky.
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I flew for a living too in USCG helos...in single engines for 10 years and twins for 10 years....NEVER had an engine burp worth worrying about.

My son flys in Navy H60s and I'm scared for him....it's not the aircraft...it's how it's flown and maintained.

I've only had one significant issue in 50 years of boating and 12 years of commercial marine operations..in vessels used so much harder than recreational craft can imagine....

So keep right on thinking twins are necessary...the economy needs stimulation...:rofl:
 
A hypothetical question to all: If you were employed as a captain by a Brokerage in Florida that needed to move one of their two new Krogen 58's to Costa Rica and the boss gave you the choice of either taking the one with twins or the single screw, which one would you pick?
 
I flew in US Navy helo's for 12 years in SH2F and SH3H and SH60B. I had a number 1 compressor failure that exploded and caused a fire in the engine. Resulted in loss of generator and AC bus. If we didn't have 2 engines I would have gotten wet. Very wet and away from home plate by 50 miles.
 
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