Okay, single or twin??

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Erikj

Newbie
Joined
Oct 9, 2015
Messages
3
Location
USA
Vessel Name
Amor Fati
Vessel Make
1977 C&L Double Cabin 37'
First large boat for me and using primarily as live on board. Planning on having slip in SF Bay Area location or possibly as far inland as Antioch. I'd like to be able to take it out and do some fishing or cruising on multi day trips.
Will I be disappointed with a single engine vs. twins?
What are advantages and / or drawbacks from either?
I've got several on my radar but have been shying away from singles.
Please let me know your opinions and why.

Thanks
 
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The boat we chartered was a single with a bow thruster. Worked great and we had no problems maneuvering/docking despite our relative inexperience operating a boat of this type.

When we decided to buy our own boat of this same make and model we didn't care if it was a single or a twin. As it turned out, the boat that best met our needs and boating budget at the time happened to be a twin. We'd never run a twin engine boat before but today, seventeen years later I can say that today we would NEVER buy a single engine boat. Ever.

There are a several reasons for this not the least of which is that I like running machines so the more engines the better (our newest boating venture is a three-engine boat).

We like having a spare engine under the floor; we've needed the spare engine in our PNW boat five times now, the latest just a few weeks ago when we were at a degree of risk of losing the boat. None of the causes had anything to do with the engines themselves but for various reasons we've had to shut one down so simply completed the run on the other one.

Very important, perhaps even more important to my enjoying messing about with multiple engines, is that my wife is more confident, relaxed, and happy with two engines under the floor.

This is a woman who's owned several single-engine airplanes and who has no qualms about flying into the remotest country in the BC Coast Range in a single engine floatplane powered by an engine manufactured during WWII. But in a boat, she wants more than one engine. And as far as I'm concerned a happy boating partner trumps every argument, pro or con, about any aspect of boating.

Do I think single engine boats are bad? Of couse not. They have their advantages and I maintain that anything that can be done with a twin in terms of maneuvering can be accomplished with a single albeit using different techniques at times.

But our personal preferences dictate that we will never own one.
 
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Ask any waterman: Two engines = twice the downtime & expense.
 
Twins,
Any fool can see a single is lacking the 2nd engine.
 
I had a single for a long time. I now have a twin. Given the choice, I'll take the twin simply for the redundancy.

At the time of our boat transition, we re-positioned both boats (my old single and new twin). The twin had a freak issue where a bolt sheared off on the water pump leading to an overheat condition on one engine. We shut it down and made it to the marina on one engine with no issue. The single blew a seal in the transmission, losing it's fluid and getting it hot. Fortunately, it happened coming out of a lock right next to the marina after a 4 day trip up the Mississippi River in the middle of nowhere. Had it happened anytime before that, it would have a been a serious problem.

More fuel, more maintenance, and more things to break. But it's the twin's redundancy that gives me peace of mind.
 
Oh no, the TS word.:facepalm::facepalm:
 
Twins, no question -- boats are a money hemorrhage, might as well open a couple major arteries instead of just one. Seriously though, having owned both, in my mind it's a relatively straightforward trade-off between (1) greatly enhanced control and safety-through-redundancy on one hand, and (2) higher expenses, lower fuel efficiency and an increased maintenance/hassle factor on the other. I don't do long runs in open water so the redundancy safety margin is not a high priority for me, but the enhanced control definitely is. For me, twins are pretty clearly worth the extra expense and maintenance.
 
....a twin screw converted to a single engine....no, wait....a single screw driven by two engines...
 
Bottom line, there are pluses and minuses to both.

You will find an interesting correlation between the answers on here and what the poster currently has. No one will say that they made a purchasing mistake.
 
Good arguments for each. And the topic gets beat to death. Comes down to your risk tolerance for an engine failure, and balancing the other pros and cons.

I'm in the single engine/bow thruster camp, and very happy with my choice.
 
We just sold our single engine trawler with a bow thruster and are in the hunt for a boat with twins. I personally missed having two engines for a lot of reasons, my wife just prefers operating with twins.
 
First large boat for me and using primarily as live on board. Planning on having slip in SF Bay Area location or possibly as far inland as Antioch. I'd like to be able to take it out and do some fishing or cruising on multi day trips.
Will I be disappointed with a sidle engine vs. twins?
What are advantages and / or drawbacks from either?
I've got several on my radar but have been shying away from singles.
Please let me know your opinions and why.

Thanks

OMG! It depends on what kind of anchor you have, and whether it is galley up or galley down. Teak decks or not often come into play. And that's just the beginning before you get into nitty gritty details like propane vs electric, sundeck vs cock pit.

Please spare the innocent here and do a search on the forum, there is so much dialog, ultimately fruitless, on this subject.
 
When choosing my boat for operating in the extensive San Francisco estuary, selected a keel-protected single propeller because much of the waters are shallow. Assistance can be readily obtained so one doesn't need a second engine/propeller as a backup, nor double the maintenance/breakdown of twins. ... A bow thruster can be handy when maneuvering approaching/leaving a dock.

Subsequent to my 2011 boat acquisition, met two great boaters on this forum in my boating waters. Both with twins, and both experienced damage to props. One now wishes for a protected single propeller and the other (likes to fish) likes the higher speed provided by twins.



Take your choice. It's your money. (By the way, I'm of the minority opinion: the vast majority of our "trawlers" have twin engines.)
 
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I think the bigger question Is

Do you really want to live on a boat? Living on a boat in a marina is perhaps a cheaper way to live on water front property in the Bay Area, assuming you can locate a livaboard slip and are willing to pay the premium to do it. But you give up a lot of things you may not have thought about. Things like a garage, a good place to store stuff, a spot for your bike were it won't rust, privacy, safe parking for your car, on smaller boats appliances that aren't rv quality, heat, and a real mattress. Oh yeah did I mention privacy.
 
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Advantages (in order of importance)

Twins
- Better manoeuvrability
- Redundancy

Single Engine
- Protected prop & rudder
- Better accessibility
- Lower costs
 
Advantages (in order of importance)

Twins
- Better manoeuvrability
- Redundancy

Single Engine
- Protected prop & rudder
- Better accessibility
- Lower costs
The above quote pretty much sums it up for me.

Since 1995 I've had both. Seven twins and two singles. They all had their pluses & minuses. I finally got back to a twin engine boat after 8 years of driving a single and I'll never go back!:blush:
 
Single

Single,Bow Thruster, Vessel Assist.
 
The advantages of singles and twins can change depending on where one boats. For example, I gather from posts to this forum that vessel assist coverage along the ICW is pretty to very good. So from the aspect of having to shut an engine down, having one engine does not seem as problematical as it can be somewhere else.

Where we boat there is a maze of islands pretty much all the way from the lower end of Puget Sound up through SE Alaska. Add to this an increasingly great tidal range as one moves north--- perhaps 10-12 feet here in the Sound into the 20-foot plus range up north--- and the currents in this region can get pretty impressive, particularly in the narrower passes and channels.

Roll in the increasing scarcity to non-existence of vessel assist organizations as one moves north and what might be an inconvenient engine shutdown along the ICW can become a downright dangerous event out here.

I know boaters here in the southern waters who've come within a hair's breadth of losing their boat when it became a race as to which would happen first--- help would arrive or the current would sweep them into the rocks. And a fair number of boat have been on the losing end of this race over the years.

Farther north one is increasingly on their own when it comes to emergencies. The good news is that on the commonly used routes along the Passage there is a reasonable amount of boat traffic, particularly during the summer boating season. So help may be fairly close at hand.

But off of those routes or in the off-seasons one is more often than not totally on their own. Combine this with the strong currents, narrow passes, and almost totally rock geography the risk of a very bad outcome from an engine shutdown is not something to be taken lightly.

A common argument in favor of single-engine boats is that commercial fishing boats are generally single engine. Totally true, and it's been this way since they started putting engines in fishboats. But.... these boats are mostly crewed, particularly with the larger seiners, gillnetters, crabbers and combination boats used today. They tend to have at least one crew member who is a very good mechanic. And they have the space and capacity to carry a lot of spares and tools.

So there's a bit of a difference between the single engine fishboats that work this area and the average recreational cruisers one sees up here.

My point is not that smart boaters should only have a multi-engine boat in these waters. There may be some people who feel this way but I'm not one of them. Considering the huge number of single engine recreational boats, power and sail, that ply these waters without incident year after year it would be a foolish position to take.

But it is something to keep in mind when determining what kind of boat one wants for cruising this area, particularly if one is interested in venturing farther north and off the more beaten paths.

Based on our direct observation over the last 17 years of cruising up here we do not put as much faith in the "protected prop" advantage of a single engine boat as other people might. If we count sailboats, we know more people who have fouled or damaged their running gear in single engine boats than we know people who've had the same problem with a twin. And some of these people ended up in serious situations when it happened thanks to the conditions I described earlier.

Now we also know a few people who've fouled or damaged running gear in their twins. But in all these cases, only one side was affected. So they were able to continue home or to a port for repairs on the other side. Only one of them ended up in a potential boat loss situation and that was because a log jammed the rudders hard over in addition to bending a shaft. So they had power on one side only plus they didn't have rudder control.

The couple were in the process of abandoning their deFever which was only yards from being swept into a cliff by the increasing current when the log popped free on its own and they got rudder control back. They returned the several hundred miles to Seattle on the other engine without further incident.
 
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The above quote pretty much sums it up for me.

Since 1995 I've had both. Seven twins and two singles. They all had their pluses & minuses. I finally got back to a twin engine boat after 8 years of driving a single and I'll never go back!:blush:

Walt - curious if your singles had thrusters? (Though I do love your OA, twins or not). My single driving was all 32' - 35' sail boats. But once at or above around 38' I like the support a thruster can give when things get a bit twisted. :smitten:

I have twins, but based on my current bay/limited coastal use would be happy with a single/ bow thruster. I think given the OP area of ops, they should not overlook a good boat with single/thruster.

JMHO from a rookie boat helmsman!
 
While up in the Broughtons this summer we fouled our starboard prop with a stern line (don't ask!). Two people ended up free diving (with mask/snorkel and sharp serrated knife) approximately 35 times and STILL could not cut all the way through the mess of line. Yes, when we do something we really like to do it well! We ended up the next day motoring to the closest marina on just the port engine. No problem! There a diver was down for almost 40 minutes before finally cutting the last vestiges of a molten polypropylene plastic ball off the shaft.

Needless to say we are quite happy to have two engines. However, as I would consider having an affair with a Krogen 54 someday I believe I would be just as happy if not even happier with a single engine...
 
Advantages (in order of importance)

Twins
- Better manoeuvrability
- Redundancy

Single Engine
- Protected prop & rudder
- Better accessibility
- Lower costs

Good summary. One opinion: If you are going to stay in Marinas the ability to dock (maneuverability) using twin engines is more important than the fuel savings from having a single engine. The redundancy factor is not very important as most diesel shutdowns are fuel related and will shut down both engines. Also with respect to redundancy some boats with twins should not be run with only one engine without taking off the prop of the engine not being used.
 
Advantages (in order of importance)

Twins
- Better manoeuvrability
- Redundancy

Single Engine
- Protected prop & rudder
- Better accessibility
- Lower costs

The are exceptions to that like the Great Harbours that have twin keels and they have enough beam that engine accessibility is not an issue.
 
Advantages (in order of importance)

Twins
- Better manoeuvrability
- Redundancy

Single Engine
- Protected prop & rudder
- Better accessibility
- Lower costs

Re protected running gear, depending on design many (maybe most) true displacement and a lot of semi-displacement hulls give protection to twin gear.

Modified planing - not so much.
 
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The redundancy factor is not very important as most diesel shutdowns are fuel related and will shut down both .

Not sure how valid the fuel argument is, certainly not for those of us who get a fouled prop from a stern tie or dinghy tow line. Maybe psneeld could chime in with tow boat thoughts on reasons for failure.

An interesting comparison is Krogen's order book for the 52. The more popular choice (or it was two years ago when I was looking at a new build) is twins with about a 10% observed fuel penalty over a single. Oh, Krogen is quite happy to install a get home on their new build single installations as are many other single builders like Selene, Dashew and Nordhavn (close to 100%).

Either setup will fail the inattentive owner though, keeping pros like Ski in business.
 
Good summary. One opinion: If you are going to stay in Marinas the ability to dock (maneuverability) using twin engines is more important than the fuel savings from having a single engine. The redundancy factor is not very important as most diesel shutdowns are fuel related and will shut down both engines. Also with respect to redundancy some boats with twins should not be run with only one engine without taking off the prop of the engine not being used.

Couple of things here.

Many well designed trawlers feed two fuel tanks into a day tank, or operations tank. This allows the operator to better manage fuel quality (e.g. running off one tank until at 1/3 or half, then filling that tank and running off the other). By good management you can reduce the impact of a bad fuel fill since you will have fuel from two locations in your tank. I recognize not all vessels are set up this way though.

Regarding running off one engine. Engine/transmission manufacturers test this and a quick call to the manufacturer will give you peace of mind. For example my Crusaders and Borg-Warner velvet drives do allow this for as long as you want without having to lock down the non-running shaft.
 
One thing I notice is noise quality. With twins there is always a bit of a beat frequency from the engines being even slightly off sync. Just a pet peeve of mine, a truly minor issue.

Also, mine being a single, I know the engine must be as reliable as possible. So it gets first rate maintenance, issues are handled right away, wiring is first rate, a good set of spares and tools carried.

I sea trial boats as part of my business and many twins are treated differently: "Hey I've got two, if one poops, I can still get in.." Neither particularly well maintained. Well if one poops, it still is going to screw up your trip!!

I'm not discounting the advantages of twins, those are real.
 

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