Trawler - Single Engine vs Twins

[Tom.B]

It isn't such the chore that some would have you believe. You will get used to maneuvering a single soon enough. With or without a thruster.

One other point to note. In the world of "smaller" trawlers that you are looking for, be aware that engine room access is very bad with twins. Getting everywhere you need to on engines take a lot of flexibility... or a Disney movie shrinking ray gun. :-) And you can bet the farm that whatever breaks in the middle of a cruise will be on the OTHER side of the engine from where you can get to. Singles give you much better access.

[Scout 30]

Another problem not previously mentioned is noise. The less noise the better & twins will be louder than a single diesel in most cases. The never ending noise of the iron genny is one thing that will have you reminiscing about your sailboat.

[brantleychuck]

Schucker 436 motor sailor is the answer


Sent from my iPad using Cruisers Sailing Forum

[Cadence]

Originally Posted by brantleychuck

Schucker 436 motor sailor is the answer


Sent from my iPad using Cruisers Sailing Forum

Or something with a get home sail and a stay sail if needed.

[Terra Nova]

Having owned twin-screw boats to 48' I must recommend a single, which is much more reliable and dependable (~1/2 as many things to go wrong), much easier to maintain (don't forget there's much more room to access a single engine). Additionally a single propeller and rudder are protected by the keel. Twin screws/rudders are dangerously exposed.

[Sunsetrider]

I am planning to head down into adventure-land next year when I (hopefully) retire - in my single-screw diesel Albin 25. I currently have a port (bow in) finger dock with a counter-clockwise prop, so have been practising reversing in so that I can use the "brakes" when docking. Reversing the prop kicks the stern to stbd, possibly into my slipmate if I am docking bow-in. I'm still working on it, but I'm confident I will emerge victorious(ly).

I've had my fuel tank flushed and the fuel lines and filters rationalised with expert assistance, mechanical pump replaced with new, all new battery-room wiring, etc.

I'm not sure what my fuel usage is, since this boat doesn't actually seem to use it in any noticeable way.

[poiu]

Originally Posted by Capt Phil

Truer words were never spoken, Scout! The number of times I went over the side at Catalina with my hooka setup to untangle the mooring lead line from twin screw props is more than I can count on my fingers and toes!
Twins just seem to drag in everything. I had a fortunate outcome driving down the coast from Port Townsend years ago and ran over a floating line about 1 1/4" in diameter. Thank goodness one of the crew on the bow saw it and hollers LINE which gave me time to throw the vessel into neutral and it hung up on both stabilizers. We managed to floss it off and left it on the Coast Guard dock in Fort Bragg. It could have pulled one of the shafts completely out had my crew not spotted it. Phil

I have hooked rope on my sailboat keel and rudders and stationary prop many times, but never on the prop when motoring, so I believe it is doing it's job. I saw it cut a 7/8" rope without a stutter at only 750rpm.

Can't you fit rope cutters to trawlers?

[kmacdonald]

Single with lots of spare parts, not that you'll need them if you have them.

[ranger58sb]

Originally Posted by climber49

I
The only advantages I see to the twins are maneuverability, which is not a big deal to me, and redundancy. That's my primary issue. I know diesels are reliable and that fuel issues comprise the vast majority of problems, as long as you do the proper routine maintenance. But......

What I am planning on is installing dual primary filters in parallel so I can switch them quickly and having at least 6 spares of 10 micron, carrying one extra complete water pump plus spares for at least two rebuilds, a full set of spare belts, hoses and clamps, a minimum of six engine fuel filters, four spare oil filters and enough oil for two changes, an oil change kit, extra coolant, extra transmission fluid, and an adequate set of tools. I am considering building a small fuel polishing unit so I can filter a tank either by recirculating or by discharging the cleaned fuel to the second tank.

What else can I do? Any suggestions on parts or other supplies?

I can be comfortable with a single (we had one), even recommend it, to some.

We have twins now, and I had my first get-home-on-one-engine episode last weekend. Slight drip in starboard Racor, lost prime, sucked air, engine shut down... I was single-handing so couldn't fix while underway or adrift... and didn't choose to fool with the anchor. Good weather, a pleasant 6 hours at 5 knots, what's not to like?

Where we are, and in that weather, the tow boat (with unlimited towing insurance) would have been a fine solution. Might have been slightly less comfortable or maybe more worrisome if the weather had been bad, but I had options, and I could use the port engine to exercise those.

But that incident doesn't change my mind about whether a single diesel installation can be workable, even maybe "best" for some folks.

Thoughts on your list: some spare diesel, or create a separate diesel source or a rerouting system, in case you need to refill a fuel/water separator while underway.

Otherwise, you'll likely be fine with a single diesel, a bow thruster would be nice... just get on with life, don't worry. (Planning ahead is not the same as worrying.)

Rethink your list: engines need whatever density filters the manufacturer specifies. For example, if your engine calls for 30 micron primaries, 10 micron filter elements might put more strain on the lift pump than is necessary. And then you'll want spare filter elements for the primaries and spare secondaries, at whatever density is called for on each.

-Chris

[Defeverboat]

When docking in high wind you need two engines or bow thruster. I know of a Ocean Alexander with a single screw that had h--- getting in his slip had to walk it in by ropes.

[Sea Life]

Don't let the what ifs drive you crazy. Pick a good hull design that has the accommodations you want. The number of engines will choose itself. We have a single and left Maryland a year ago. We are now in Panama. Sure a wing engine would be great, but would it be worth a year or two of cruising budget? Time will tell.


Scott

[jeremiason]

Originally Posted by Cadence

Backing a trawler, single screw displacement, is not a problem with a barn door rudder with a good amount of leading edge on it. Most twins have postage stamp rudders, ever see someone dock a twin with the helm.

Even with a "Barn Door Rudder", you are assuming you are backing in calm conditions with little or no wind...

Trawlers have lots of windage and barn door rudder or not, at some point the wind will over take the rudder and leave you with compromised steering.

In my experience with trawlers, the rudders lose effectiveness in winds between 10 and 15 knots, which in the Gulf of Mexico and Caribbean isn't unusual.

When I was operating commercially, I operated power boats up 165 feet with single and dual engines on the San Francisco Bay. What I learned is that a bow thruster is a nice thing to have when the conditions are not perfect or even just to make your life easier.

Today, thrusters are used regularly in the Recreational market and the prices have come down considerably. Many used boats already have them installed.

So like I said before, it isn't that you can't back a single screw boat without a thruster, but there will be times not having one will be an inconvenience at best and other times impossible without one.

So given the choice, in my opinion, I would not buy a single screw trawler one without a bow thruster.

[jjorg]

We made this move three years ago. Very happy with our single screw but I also highly recommend a bow thruster. The small rudder combined with more windage on the trawler make this much more to handle than our sailboat. I really appreciate the space in the engine room and the protected prop on the single.

[montenido]

I will add a little more info about my twin motored vessel, because apparently, according to some of the generalities being tossed around, it is unusual for a twin. I have great access on all sides of both motors and the generator in the engine room. Yes, you can't stand in there, but it is plenty roomy, especially compared to some of my sailboats. Each of my main motors has its own fuel tanks and filters, so a fuel problem with one motor does not mean the other will be effected. As others have mentioned, fuel burn is pretty low if you are not at WOT (5gph at 8knots, 1600 rpm). Yes, there is twice the maintenance with 2 motors, but in Mexico, if you lose your single motor, you will be waiting for a passing cruiser to get you back to port.

I guess I must be defensive because I like my twins so much. To each his own.

Cheers, Bill

[Cadence]

Originally Posted by jeremiason

Even with a "Barn Door Rudder", you are assuming you are backing in calm conditions with little or no wind...

Trawlers have lots of windage and barn door rudder or not, at some point the wind will over take the rudder and leave you with compromised steering.

In my experience with trawlers, the rudders lose effectiveness in winds between 10 and 15 knots, which in the Gulf of Mexico and Caribbean isn't unusual.

When I was operating commercially, I operated power boats up 165 feet with single and dual engines on the San Francisco Bay. What I learned is that a bow thruster is a nice thing to have when the conditions are not perfect or even just to make your life easier.

Today, thrusters are used regularly in the Recreational market and the prices have come down considerably. Many used boats already have them installed.

So like I said before, it isn't that you can't back a single screw boat without a thruster, but there will be times not having one will be an inconvenience at best and other times impossible without one.

So given the choice, in my opinion, I would not buy a single screw trawler one without a bow thruster.

You're right about the wind. I think experience makes a difference. I would marvel at the job some shrimpers with 70+ single screw trawlers would do at docking. I would also marvel at some of the awful attempts made by people with twin screws.