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Old 10-09-2015, 11:54 PM   #21
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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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Old 10-10-2015, 12:08 AM   #22
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Originally Posted by Codger2 View Post
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!
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.

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!
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Old 10-10-2015, 12:42 AM   #23
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Originally Posted by Roughin'it View Post
Single,Bow Thruster, Vessel Assist.
So how does vessel assist work when you are north of Vancouver, say 800+ miles north
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Old 10-10-2015, 01:49 AM   #24
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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...
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Old 10-10-2015, 05:29 AM   #25
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Originally Posted by AusCan View Post
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.
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Old 10-10-2015, 06:20 AM   #26
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Quote:
Originally Posted by AusCan View Post
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.
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Old 10-10-2015, 06:56 AM   #27
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Originally Posted by AusCan View Post
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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Old 10-10-2015, 07:54 AM   #28
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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.
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Old 10-10-2015, 08:03 AM   #29
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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.
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Old 10-10-2015, 08:06 AM   #30
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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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Old 10-10-2015, 08:24 AM   #31
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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.
You don't happen to be a pilot so you! I once had a discussion with a pilot/boater. He said that out of sync twins were his biggest peeve since flying jets he was attuned to well synced engines and was trained/experienced to tune consistently!
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Old 10-10-2015, 08:26 AM   #32
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The one comparison that kinda sticks out is how many single engine planes are flying.

They are just maintained correctly.
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Old 10-10-2015, 08:41 AM   #33
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Ask the question of the crew of the El Faro when you get a chance...
If you could talk to the captain, I suspect he would report that it is bad luck to work on the engines / propulsion during a hurricane...
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Old 10-10-2015, 08:44 AM   #34
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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.
Get an engine sync and you won't have the drone of slight variations of twins.

Nothing is foolproof to a sufficiently talented fool.
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Old 10-10-2015, 08:49 AM   #35
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Several factors come into play in the decision process:

Fear or break down can certainly be resolved by vessel assist if their available in your area, as is the case for probably 90% of TF members. If you plan to cruise in extremely remote areas, one can make a case for twins. However a number of our members travel to extremely remote areas including crossing the Atlantic with a single.

Are or will you be an infrequent boater as most on this forum. Proficiency in general comes from frequent repetition. If you consider that well over 90% of commercial fishing boats under 60' are singles, then it's easy to see that maneuverability is a limitation of the operator in most cases and not the vessel. With the exception of the need for more HP than a single can provide, in many cases, twins are a crutch for lack of docking proficiency. Adding a bow and even a stern thruster to a twin is the second crutch. Don't agree with this? How many sailboats under 60' have you seen docking with twins?

How do you feel about engine maintenance? While not a hard and fast rule we see far more breakdowns of one engine in a twin engine boat than single engine boat breakdowns. There are a lot of boaters that view twins as redundancy and consequently do very little maintenance assuming that when one breaks the other will get them home. This doesn't apply to everyone with twins, but I would wager it was the majority in recreational boating. In general, single engine boaters tend to be more preventive maintenance oriented for the obvious reason. Yes there are those that don't do PM regardless of how many engines they have.

One can debate whether a single protected screw makes more sense than twins when running aground. I would argue that learning to navigate and avoiding shoal waters is a far better choice.

So to my mind, the choice of single versus twins is really more based on what type of owner operator you will be. If you will be an infrequent user, not big on PM, and have a phobia regarding engine failure, twins would be a logical choice.

For the incredible complexity and unreliability of the modern engine, wonder how many twin advocates on this forum wouldn't have a single engine car.

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Old 10-10-2015, 09:12 AM   #36
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I believe that a neglectful owner will be neglectful and a meticulous one will be meticulous single screw or twin, so I don't really buy into the "twins are less maintained" argument.

If the OP's cruising area has towing service available, I think a single will be fine. If there's no towing service, I would opt for twins or a single with a get-home set-up. Peace of mind is very important to me.

If there were a "get-home genie" going around offering free get home engines to single screw boaters, I'm sure most, if not all will take the free offer. Even those that claim to not believe in the value of redundancy.
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Old 10-10-2015, 09:18 AM   #37
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"One can debate whether a single protected screw makes more sense than twins when running aground. I would argue that learning to navigate and avoiding shoal waters is a far better choice."

Great where the Hooligan Navy is there to set buoys for you , but the reality is if you go cruising you WILL run aground eventually.

Trees ,trash in the water and thin water play havoc on exposed shafts , props and rudders, never mind the occasional sea land container.

There probably is no "best" so the concept of purchase the interior you like and deck house style that you think is attractive probably does work as well as dithering.

The best advice is probably to purchase a boat that is currently doing just what you want to do, and save months and thousands in "conversion" or "upgrading".

A cruiser is outfitted as a cruiser a cottage as a cottage .
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Old 10-10-2015, 10:20 AM   #38
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So to my mind, the choice of single versus twins is really more based on what type of owner operator you will be. If you will be an infrequent user, not big on PM, and have a phobia regarding engine failure, twins would be a logical choice
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Speaking of phobias, I heard about a guy who was so OC about the singles vs twins discussion on TF that he removed two perfectly good engines and put in one
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Old 10-10-2015, 10:24 AM   #39
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When I look at the working boats in this area all I can say is that they are 100% singles. These are boats that are out on the water 10-12 hours a day 6 days a week. I am talking about lobster boats generally in the 35 to 50 foot range with most 35-45 feet. They don't seem to have much trouble with engine failures. Sure they do happen and they very occasionally result in the loss of the boat (largely because lobster boats often work close, as in 10-20 feet, from ledges and rocks, where a blown transmission results in the boat being on the rocks in seconds). Reliability of a properly maintained diesel really isn't much of an issue. Incidentally, there is no towing or vessel assist around here. We also have 12-15 foot tides locally and up to 25 foot tides a few miles further down east with the associated currents. On top of that if you go more than three miles from the harbor you are in the open ocean where things can get nasty fast.

As far as maneuverability is concerned, I think what you are really talking about is ease of maneuvering. If you know your boat and have significant experience with it, maneuvering isn't a problem. I see lobster boats come into tight spaces all the time without any trouble. That is a boat that is often single handed, with a single engine and no bow thruster.

I have always had singles and really don't feel the need for twins for any of the reasons noted above. Maintain your engine properly and know your boat and you won't have any problems with a single.
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Old 10-10-2015, 10:39 AM   #40
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The one comparison that kinda sticks out is how many single engine planes are flying.

They are just maintained correctly.
There are more planes in the water than there are boats in the air.
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