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Old 12-20-2014, 03:26 PM   #61
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We do, did 5,000 miles to Mexico and back and now heading to Alaska in 2015.

Like others have said, it's all about your comfort level and maintenance abilities. My wife thinks I have a girlfriend hidden in our engine room I spend so much time there. Mostly doing inspections of all things breakable.

Since we have a fully protected prop, we worry less (but still a lot in our minds) about wrapping the prop, one advantage to a single. Cutters would certainly help and we are installing this winter prior to heading up the coast to the inland passage.

I have also developed a spreadsheet that automatically reminds me of my maintenance schedule. I have daily (when cruising), monthly, quarterly and items based on the engines hours that constantly remind me of the tasks to complete. So far so good.

We do also have lots of safety gear on board including a sea anchor if we do get disabled. The prior owner did use this once when he got wrapped in bad weather. We have scuba & hooka gear on board as well.

Our future plans are to take Antipodes around the world. YMMV.
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Old 12-20-2014, 03:30 PM   #62
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IMO the efficiency of a displacement boat has a lot to do with minimizing drag and the efficiency of propeller location. Twins have twice as much gear hanging in the water, not in alignment with the keel, and probably has two rudders to drag along as well.

Most twins have enough power to push the boat at displacement speeds with one engine, the redundancy is for peace of mind and really only improves handling when docking. On a single the propeller is optimally placed behind the keel, offering excellent protection from everything but bad luck. Even pot lines have a tendency to push off a displacement hull and seldom foul, twin have their running gear in an optimal position to pick up anything in the water and wrap it up, as well as maximizing drag since everything is mounted off the hull and is breaking fresh water constantly.

I have run from Seattle to Prince William Sound twice in single engine boats without a hitch. I never would have been able to make the distance with twins and the fuel capacities of my boats.
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Old 12-20-2014, 04:41 PM   #63
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Having owned and cruised aboard single engine boats I will concede the efficiency and running gear protection edge to the single. Having the experience of losing my single motor(273 hours on motor) in a fashion un- repairable by me or local engine repair people in the PNW I now travel those areas with two engines. I do have to watch for logs but I did that with the single propped boat. I have experienced a big plus in The added maneuverability in the tight marinas I frequent. As for fuel burn I average about 200 hours/year of engine time. At 9.2 K We burn approximately 5 gallons per hour and do better at 7 or 8 k. The difference in fuel cost is very small when compared to the other costs of keeping and amortizing a 34.000lb almost 50 ft boat. So there are obviously two sides to this coin. Due to our past bad experience we prefer the twin motor side and before this event we were quite content with one engine.
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Old 12-20-2014, 07:54 PM   #64
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Doug wrote;
"IMO the efficiency of a displacement boat has a lot to do with minimizing drag and the efficiency of propeller location. Twins have twice as much gear hanging in the water, not in alignment with the keel, and probably has two rudders to drag along as well."

I don't think so. The thickness of a single engined boats keel is much wider in order to accommodate the shaft. And the shaft and struts on a twin are much smaller than a single. Two of them of course but much less drag each. Also the rudder need not be partially deployed causing more drag to compensate for the prop walk.
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Old 12-20-2014, 10:01 PM   #65
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Rsysol, what makes your prop fully protected and from what?
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Old 12-20-2014, 11:32 PM   #66
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The boat's keel is a given, with the prop incorporated into the keel there is 0% additional drag from struts. With twins you still have the keel, plus two sets of struts and a great deal more exposure. I do not buy the argument of the keel being thicker in order to handle the cutlass bearing, the keel will be "beefy" in a full displacement vessel, regardless. Mine is a uniform thickness from bow to stern and the cutlass bearing fits easily within it's width. The Nordy 40 I looked at in Anacortes likewise, admittedly a small number of single engine trawlers I have seen out of the water. Prop walk is prop walk, and rudders counter it. I am unbelieving that singles have more prop walk than twins when underway... IMHO
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Old 12-21-2014, 03:23 AM   #67
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The keel on a twin engine Grand Banks is exactly the same width as the keel on the single engine version of the same boat. The only difference is the keel of the twin is cut up in a reverse curve to fair into the afterbody of the hull instead of terminating in the propeller opening and rudder shoe.

As to forward propwalk in a single I don't believe it's that significant of a force, particularly in a cruiser with a keel. Going backwards with very little way on the boat, sure it's going to move the stern sideways. But I would be surprised if going forward it requires enough rudder offset to even be noticeable as a component of drag and fuel burn.

A single will experience more propwalk effect than a twin if the twin has counter-rotating propellers, which most of them do. Notwithstanding the effects of current, waves, and wind, we can back our twin in a straight line all day with the rudders centered because it has counter-rotating props. The propwalk force from one is cancelled out by the propwalk force of the other one.
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Old 12-21-2014, 11:53 AM   #68
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AKDoug,
You've got a pretty good point re the keel but the TE of the keel is a draggy point on most trawlers. Prop walk ... counter rotating twins don't have any prop walk to correct. But the difference is mostly in the boat and single v/s twin is fly stuff and should almost never be mentioned. OK I'll stop.

Marin wrote;
"The keel on a twin engine Grand Banks is exactly the same width as the keel on the single engine version of the same boat"
That's poor cheap boatbuilding. A proper twin would have a better keel unique to the twin. Opps I said I'd stop. It really is fly stuff. But so many crow about the single being so efficient as if they knew something important. The difference is so small that quite a few twins are probably more efficient that singles and quite a few singles are more efficient because their engines are bigger. Many more of them are turbocharged and more efficient for other reasons. This "singles are more efficient" thing is like a bandwagon w no place to go.
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Old 12-21-2014, 12:42 PM   #69
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Probably been posted elsewhere, but another consideration is with twins there is simply more equipment to fail. Many failures are not severe enough to take the engine out of service, but are enough to cause the mariner to change plans to effect a repair. Twice as often.

A friend has a twin with 3208's, and in the last four months he has had an incredible run of bad luck with the engines: 1. stbd injector line broke on left bank. 2. plunger in injection pump stuck on port. 3. stbd injector line broke on right bank. 4. governor rack stuck at no fuel on port. Each failure caused a canceled trip, that's four trips. In each case the failed engine could be run with some creative fixing, but it was decided not to as other one was going ok. Just looking at the probabilities, if boat was a single with one of those engines, it would have two failures, not four!!

This friend has been a bit tolerant of iffy things on the engines, in part I think because- "hey, I've got twins". On my single, since my engine is more sacred than his, anything that gives me the "iffies", gets handled right away.

Prop fouling is also way more likely on a twin. On my single, I have run over things that came into view at the last second, dead on, and the vee bottom pushes it one way or the other, fortunately taking it clear of the prop.

I'm not suggesting that a single is best for everyone, it is not. Certainly there are benefits to twins. Maybe I'm just trying to make myself feel confident of my single before heading on a 2000nm trip!!!

As a side not, my bud with twins made it ok last night into Jax Fla from NC. No engine trouble. Whew...
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Old 12-22-2014, 12:28 AM   #70
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Here's a picture:

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Old 12-22-2014, 12:32 AM   #71
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Quote:
Originally Posted by sunchaser View Post
Rsysol, what makes your prop fully protected and from what?
Here's a picture. Full skeg protects the prop better than a twin setup.

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Old 12-28-2014, 11:55 PM   #72
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My experience single handing a 1978 Marine Trader 36 with single Lehman 120.
In the last 18 months I have done the great loop including a "side trip" to the Exumas. Then up to the Chesapeake for the summer. Currently in Fort Myers, FL. 10,000 miles in all.

None of this was terribly remote however the Georgian Bay / North Chanel as well as the Exumas felt pretty remote at the time. An engine failure on the Mississippi would not have been much fun.

I have experienced no failures. I will be headed back to the Bahamas for the rest of the winter in February. I am considering a run to the Virgins next year and perhaps further south. I really do not feel the need for a second engine but there have been times I would liked to have stabilizers.

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Old 12-29-2014, 12:00 AM   #73
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Old 12-29-2014, 12:58 AM   #74
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Post 125 on the Great Harbor thread, pics 2&3 show well protected twin props and rudders. Worth a look.
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Old 12-29-2014, 07:43 AM   #75
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Quote:
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My experience single handing a 1978 Marine Trader 36 with single Lehman 120.
In the last 18 months I have done the great loop including a "side trip" to the Exumas. Then up to the Chesapeake for the summer. Currently in Fort Myers, FL. 10,000 miles in all.

None of this was terribly remote however the Georgian Bay / North Chanel as well as the Exumas felt pretty remote at the time. An engine failure on the Mississippi would not have been much fun.

I have experienced no failures. I will be headed back to the Bahamas for the rest of the winter in February. I am considering a run to the Virgins next year and perhaps further south. I really do not feel the need for a second engine but there have been times I would liked to have stabilizers.

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Old 12-29-2014, 07:53 AM   #76
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