If you could do it over again?

Single Engine or twin? 36-40 Trawler.

Double your pleasure, double your fun.... Or will it?

I am interested in practical knowledge.....

Thanks

Finally closed on the sale of Windsound so my search for our new boat is on.

Our boat is slightly outside your range...44' with slightly oversized twins. I'd definitely still go with twins, but downsized to achieve 13-14 kts max. Shut one down for significant improvement in fuel burn. A single would be preferable to small twins that can't "semi-plane" the hull. No interest in speed limitation of a full displacement hull.

skidgear said:

Our boat is slightly outside your range...44' with slightly oversized twins. I'd definitely still go with twins, but downsized to achieve 13-14 kts max. Shut one down for significant improvement in fuel burn. A single would be preferable to small twins that can't "semi-plane" the hull. No interest in speed limitation of a full displacement hull.

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Is it common to run on one engine for fuel efficiency when cruising.?

Well....I guess I would do a single, but I wouldn't blink an eye if a good diesel pusher outboard were to appear before we go full time cruising. I'm too old and stiff to keep crawling around twin bays, and prefer the less maintenance. The additional handling advantages of twins are convenient, but I suppose the purest question of "twins vs. single" must be: If you had a choice between an equal in space, equal in terms of maintenance, and equal in fuel consumption and handling, which option would you choose on the boat you have right now.....twins or single. The answer for me would be twins. All other things being unequal (as they are), I'd take the single.

wndsnd said:

Single Engine or twin? 36-40 Trawler.

Double your pleasure, double your fun.... Or will it?

I am interested in practical knowledge.....

Thanks

Click to expand...

I would focus more on finding that right boat and not rule out either. With that said, 2 questions for me come to mind:

1. where am I mooring the boat? Sticks, or busy ports?
2. Do I enjoy a 6.5-7 knot boat? Or would a 8.5 knot's tickle my fancy (assuming full displacement and Diesel)?
3. thruster? If no thruster, I would probably want the twins for maneuverability at that size of boat. (JMO).

I have a single w/thruster and wouldn't want the twin in my situation. I have tons of space in my engine room with my Lehman, not to mention only 1 to maintain.

We live in the Puget Sound with tons of service yards if something were to go wrong. Of course I have boatus insurance for piece of mind. With that said, a properly maintained engine shouldn't have catastrophic events.

Good Luck!

A single engine has been on the "must have" list for both of the trawlers I have owned. so far so good, both boats have been relatively new. A 2004 Camano 31 bought in 2004, and a 2003 Monk 36 bought in 2008, so both engunes had low hours when I go them, both boats have good sized ruders and both had bow thrusters which are a big help. Space in engine room and ease of service were my preferences.
Good luck whichever you choose,
Steve W

Twins only now that we've run one for fourteen years after chartering a single. While I think single engine boats are just fine and have no inherent dislike of them we would never consider one were we to buy another boat.

And the vast majority of twin owners do not run on one. Comparison tests have shown the fuel savings are either non- existant or negligable unless you can remove the unpowered prop ( or feather it) . Also some boats (like ours) cannot be run on one engine unless the unpowered shaft is locked off. And the non-turning propeller generates a huge amount of turbulence which is drag. So your fuel efficiency actually goes down.

wndsnd said:

Is it common to run on one engine for fuel efficiency when cruising.?

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If fuel prices stay where they are, I believe it's gonna be... Check out the current "efficiency" string.

wndsnd said:

Single Engine or twin? 36-40 Trawler.

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Being a new guy on this forum, I'm sure you don't realize we have beat this horse to death many times!

IMHO. . . It boils down to: Where you boat, what you can afford, your feeling of safety/reliability and personal preference.

My personal preference is for twins and I have owned both.

The same boat with twin engines will cost more than a single.
Maintenance is double (considering the cost of boating,a minor expense.)
In shallow water a single with a keel may provide some additional protection to the running gear.
The twin provides you a get home backup, if one should break down.
You should have towing insurance if you have a single.
The twin is a little easier to handle and maneuver in tight quarters.
The single may be a little more fuel efficient.
Depending on the boat the twin may be faster.


I'm sure I have missed a few and there are lot's of things to weigh before you purchase and it's not an easy decision. So choose wisely.

Larry B

p.s. Yes I often run on one engine when I'm slow cruising 7 - 8 knots. With BW Velvet drives you can free wheel the transmissions with no problem. Boat is quieter and you can slow down and enjoy the beauty around you. But I can also run them both up to WOT and get in ahead of the weather or darkness. A nice option to have!!

Marin said:

And the vast majority of twin owners do not run on one. Comparison tests have shown the fuel savings are either non- existant or negligable unless you can remove the unpowered prop ( or feather it) . Also some boats (like ours) cannot be run on one engine unless the unpowered shaft is locked off. And the non-turning propeller generates a huge amount of turbulence which is drag. So your fuel efficiency actually goes down.

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Interesting. Timjet and I have data that show otherwise. Suspect it's associated with turbo engine(s) running off/on boost.

The fewer moving parts the better...especially below the waterline.

truly starting over I think I'd by the boat in the link below, pull the rear mast, finish the center cockpit as a motorsailer with a flybridge, add a bow thruster and swim platform.
http://fortmyers.craigslist.org/lee/boa/3265514129.html

Edelweiss said:

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Being a new guy on this forum, I'm sure you don't realize we have beat this horse to death many times!

"
IMHO. . . It boils down to: Where you boat, what you can afford, your feeling of safety/reliability and personal preference.

My personal preference is for twins and I have owned both.

The same boat with twin engines will cost more than a single.
Maintenance is double (considering the cost of boating,a minor expense.)
In shallow water a single with a keel may provide some additional protection to the running gear.
The twin provides you a get home backup, if one should break down.
You should have towing insurance if you have a single.
The twin is a little easier to handle and maneuver in tight quarters.
The single may be a little more fuel efficient.
Depending on the boat the twin may be faster.


I'm sure I have missed a few and there are lot's of things to weigh before you purchase and it's not an easy decision. So choose wisely.

Larry B

p.s. Yes I often run on one engine when I'm slow cruising 7 - 8 knots. With BW Velvet drives you can free wheel the transmissions with no problem. Boat is quieter and you can slow down and enjoy the beauty around you. But I can also run them both up to WOT and get in ahead of the weather or darkness. A nice option to have!!

Click to expand...

"I kind of know the basic arguments, my question was more of haveing heard the arguments, and made your decisions, would you change your mind now and for what reasons. "

wndsnd said:

"I kind of know the basic arguments, my question was more of haveing heard the arguments, and made your decisions, would you change your mind now and for what reasons. "

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NO, It's everything I was and am looking for in a boat.

Also this isn't my first power boat and I knew what I was looking for.

LB

Tw 71:

That boat is similar to our last boat before the Trawler. Ours was a Seabird 37, covered centre cockpit, ketch rigged, long keel, single Lehman, fixed windshield, swimgird, etc. since moving to the 44 C&L trawler in 1994, we haven't looked back with anything but fond memories. Present boat is a keeper.

Having had singles and twin, no question twin is what I would keep.

I had to learn to back a long keel single, without a thruster. It can be done without much trouble, you just have to learn how.

Never run on just one, as that would be inefficient. Imagine the losses inherent in pushing from the corner instead of from the middle of the stern, plus turning the extra prop, trying to warm up the extra transmission. If most trans mfgrs want you to lock the shaft, that can only be due to the heat generated by the turning gears in the trans and no lube running through at the time. Think of the energy required to generate that heat. All wasted. So no, I don't buy the argument that one can be more efficient than two. Efficiencies are there, but mostly by keeping the height of your wave down.
Also, the cost of maintenance for two is still next to nothing compared to the cost of keeping the liquor cabinet full. What have I had to buy this year to maintain my engines? 2 oil filters, 5 gals of oil, 2 Racor 2010 fuel filters, 2 on-engine fuel filters. All told: $150 or so.

The liquor cabinet, otoh... I don't want to know.
what is that old saying? "if the boat ran on Gin and I served diesel, I'd be a lot farther ahead".

koliver said:

Tw 71:

Never run on just one, as that would be inefficient. Imagine the losses inherent in pushing from the corner instead of from the middle of the stern, plus turning the extra prop, trying to warm up the extra transmission. If most trans mfgrs want you to lock the shaft, that can only be due to the heat generated by the turning gears in the trans and no lube running through at the time. Think of the energy required to generate that heat. All wasted. So no, I don't buy the argument that one can be more efficient than two.

Click to expand...

Here's some real world numbers for running with one free-wheeling versus two...

44' twin, semi-planing hull, 30,000 pounds, calm wind and water, speed measured on both speed log and gps. Turbo charged engines. Fuel burn from prop chart.

1550 rpm x 2 - 9.4 mph - 4gph/2.3 mpg
1850 rpm x 1 - 9.4 mph - 3.1gph/3mpg

Not clear about conclusion that most manufacturers want the shaft locked. Twin Disk does have time limitation where they want the engine started to run lube pump for short period. Velvet drive is good to go. I don't know about others....I take it you've investigated?

skidgear said:

Here's some real world numbers for running with one free-wheeling versus two...

44' twin, semi-planing hull, 30,000 pounds, calm wind and water, speed measured on both speed log and gps. Turbo charged engines. Fuel burn from prop chart.

1550 rpm x 2 - 9.4 mph - 4gph/2.3 mpg
1850 rpm x 1 - 9.4 mph - 3.1gph/3mpg

Not clear about conclusion that most manufacturers want the shaft locked. Twin Disk does have time limitation where they want the engine started to run lube pump for short period. Velvet drive is good to go. I don't know about others....I take it you've investigated?

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similar experience...running on one in many cases IS more economical...just not always that easy...

I'd go for a single again. I like the low maintenance. And with a bow thruster it's as easy to manoeuver as a twin. Well actually, maybe not but after 3 seasons I can put the boat wherever it needs to go in whatever conditions. I can even say that now docking is my favourite part of a good boating day.

All good comments and observations. I learned to sail on a tidal river where we commonly see 3.0 + knot currents. However, I keep my boat on a mooring and when I cruise I either rent moorings or more commonly drop the hook. Maybe that will change when I start trawler cruising, but I don't really see my habits changing where I will be using slips. I also don't thi k I will be making more trips to the fuel dock.

Based on everyones advise I don't think it will be a deal breaker on my decision for a boat. But I am leaning towards si gle screw with the good advice os a towing policy!

I think I can speak for myself and Tom. Skinny Dippin' is our first boat bigger than a ski boat. And having not known then what we do now......We would both still make that same first choice. Single engine. single head, single everything made it easy to learn. 35' was a little intimidating for a few months, but soon it was comfortable. Had we known back then that we would get totally hooked and want to cruise the islands, yeah, we might have made a few other choices. But we have to remind ourselves that we're in our mid 40's so our time to shoot for the islands is still a few years off. And if we actually hit the lotto to go early, would it be a Fleming, a Selene or a Grand Banks Aleutian is all relative to the lotto win. Our little boat can take us to where we want to go as long as we have the time to get there.

Yes, Skinny Dippin' is still a great little boat for the cruising that we do.

after having both I want a single with thrusters

It's hard for me to imagine the crampness of an engine room with two primary engines, let alone with a genset in addition, in a 40-something-or-less vessel. Now I realize why most "trawlers" around me have such high superstructures.

For short and long-term cost efficiency, I chose a single engine (and no genset) with a bow thruster.

Marin sounds correct about twin-engined boats being inefficient running on a single engine, and I'd add based on verbal and written accounts, very difficult to maneuver.



(The Coot is leaning as I hadn't yet balanced the fuel among tanks after filling the starboard tanks.)

I'd still get twins.

Not because a single is any worse or better.

I feel safer with twins, and that feeling even if unfounded is important to me.

markpierce said:

Marin sounds correct about twin-engined boats being inefficient running on a single engine, and I'd add based on verbal and written accounts, very difficult to maneuver.

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We've had to maneuver and dock our boat on one engine twice. I would not call it at all difficult. You have to think through what you're going to do but once you have a plan it's pretty straightforward.

Underway with one shut down is annoying because the locked- off prop generates a lot of turbulence which buffets the rudder and steering. And you lose speed because of the drag of the unpowered prop and the need to compensate for the asymetrical thrust which creates more drag.

If I was to do it again my preference would be 48/52 ft Raised Pilot House with a single engine, bow thruster and active fin stabilisers.
Plus flopper stoppers for when at anchor.
The other main items are main deck toilet/shower and a full walk around main bed.

I would without a doubt do a single engine again...with a thruster either bow or stern. Room to work on everything, cheaper to maintain, and if it goes, yank it and put in another, no questions. Plus I like the skeg protection for the prop.
I would like to try a different style though as I dearly miss a real cockpit.

How/Why do we continue to discuss the single/twin topic? Come on y'all. Give it a rest!

GonzoF1 said:

How/Why do we continue to discuss the single/twin topic? Come on y'all. Give it a rest!

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Because the OP asked.

If I were to upgrade now, I would look for a single screw with a wing engine and a bow thruster. My second choice would be twins which is what I currently have. The redundancy is worth all the negatives to me. If you are a good mechanic and have plenty of spares, or you're not planning on boating in areas with no tow service, then redundancy may not be all that important and will be just for convenience.

markpierce said:

It's hard for me to imagine the crampness of an engine room with two primary engines, let alone with a genset in addition, in a 40-something-or-less vessel. Now I realize why most "trawlers" around me have such high superstructures.

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In this picture I was showing David James how cramped it is in the engine room.





That is the generator in the rear.

markpierce said:

(The Coot is leaning as I hadn't yet balanced the fuel among tanks after filling the starboard tanks.)

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And here I thought you kept the bar stock to starboard.