Single or Twin Screw!!

Ejdakins said:

Twins ! Power than Pretty.
2-12V71's

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Bad Ass looken boat in yer avatar!!

FlyWright said:

If anyone is looking for a good search tool, try the link at the bottom of each of my posts. It's worth bookmarking if you'd find you use it a lot like I do.

Art, No good pics from fore to aft. It's too big for cellphone photos. I'd need a telephoto lens. hide

Suffice to say that I can pretty easily crawl around each of my engines to reach all sides. By crawling over the tranny case, I can complete the circle around each engine. Mind you, there are Perkins inline 4s not Cat V8s. Where I lack ER space is above the engines. They're a tight fit vertically.

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"... too big for cellphone photos." Sounds political to me!! - LOL

ranger42c said:

No bad questions... and the pot can stand stirring from time to time, anyway.

Ref the search function: yep, you got that right. The other forum has a drop-down option already for a Google Custom Search, but this one doesn't. FWIW, and as PSN said... it's usually more responsive, especially on more complex questions, to just use Google, use whatever search argument, and then specify site:trawlerforum.com.

For maintenance purposes, I'd have a single in a heartbeat, and these days, yep, bow and stern thrusters both would be nifty. But we've got twins... because we had to find the boat that suits, first.... and that's the way the boat comes. No huge downside, except for the additional periodic maintenance/service costs... assuming nothing catastrophic happens.

-Chris

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At 81 I will take any Screw I can get.

With regard to safety because of twins redundancy, please note that the F-16 and most other military combat aircraft, virtually every civilian aircraft, and your personal automobile have single engines. Maintenance with twins in vessels less than 60 feet is greatly compromised. The strongest argument for twins is low speed maneuverability, and bow and stern thrusters negate that argument.

Landshark said:

With regard to safety because of twins redundancy, please note that the F-16 and most other military combat aircraft, virtually every civilian aircraft, and your personal automobile have single engines. Maintenance with twins in vessels less than 60 feet is greatly compromised. The strongest argument for twins is low speed maneuverability, and bow and stern thrusters negate that argument.

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Not sure you can compare military combat aircraft with pleasure boat propulsion...

One's maintained under an intensive service schedule with highly trained mechanics under a nearly unlimited repair budget...

The other is likely to have the hatches opened once or twice a year whether they needed it or not, and that was most likely due to the fact that the ER is where Bubba keeps his extra case of rum...

Apparently I hold members of this forum in higher regard than you with regard to maintenance of their vessels.

Landshark said:

Apparently I hold members of this forum in higher regard than you with regard to maintenance of their vessels.

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Apparently you're in need of some smileys to correctly interpret my next tongue-in-cheek post... they look like this ---->

Sheeesh... passive-aggressive much?


My point still stands. Good day.

There are many reasons to consider twins over singles besides just the drivel often beat to death.

Something as simple as bypassing a high cost area when repairs are necessary to get to a better, or lower cost facility can be huge.

There are many more. Manueverabiity and some of the more common reasons are small potatoes in the big scheme of things.

But every captain, boat and situation is different making the debate.....endless .....unless applied with specifics.

psneeld said:

There are many reasons to consider twins over singles besides just the drivel often beat to death.

Something as simple as bypassing a high cost area when repairs are necessary to get to a better, or lower cost facility can be huge.

There are many more. Manueverabiity and some of the more common reasons are small potatoes in the big scheme of things.

But every captain, boat and situation is different making the debate.....endless .....unless applied with specifics.

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Good one! "Something as simple as bypassing a high cost area when repairs are necessary to get to a better, or lower cost facility can be huge."

First time I heard or even thought of that one. Guess it takes a very experienced boat-tow expert to have that one in thought pattern...

Art said:

Good one! "Something as simple as bypassing a high cost area when repairs are necessary to get to a better, or lower cost facility can be huge."

First time I heard or even thought of that one. Guess it takes a very experienced boat-tow expert to have that one in thought pattern...

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Got plenty more.....and it's as much from my own experiences ( read pocketbook) as towing or USCG missions.

psneeld said:

Got plenty more.....and it's as much from my own experiences ( read pocketbook) as towing or USCG missions.

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And don't forget the possibility of postponing expensive or time consuming repairs by simply running on one for a few weeks or for the whole season. No lost vacation time.

There isn't a reason for debate it's just personal preference. Some people are glad to accommodate the added expense and work required to have twins in order to enjoy what they perceive as benefits. Others like the relative simplicity and economy of singles while accommodating any imagined shortcomings. My preference is not necessarily your preference, I like plaid pants and you may not, although I can't imagine why you wouldn't.

As pointed out by Art, some peoples preferences are based on less tnan total info....thus tne ever continuing debate.

Not tnat any one or set of advantages make it a clear choice, it does for some once the pro and con lists grow big enough.

Money spent isnt imaginary, whether on PM or yard/motel costs in tourist areas with a lousy service reputation.

Brooksie said:

Single screw: more efficient, 1/2 problems, 1/2 maintenance expense.
Twins: Many things can take out both engines on a twin anyway. Harmonic noise. Can require tanks to be off of cg best location, Space lost, extra weight.

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Brooks
I take it you don't like twins? I was interested in " many things can take out both engines" - what are these things? Please don't say bad fuel, which has a whole host of preventative measures if put into use.

Landshark said:

Maintenance with twins in vessels less than 60 feet is greatly compromised. .

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I've been in many twin ERs, under 60', that have excellent maintenance access. The list is long but I'll toss out a few. Nordhavn, Alaskan, Grand Banks, DeFever, KK and many more.

My experiences towing twins are often captain rather than boat related. If boat related, different setups might prevent most.

Twins that requested towing were fuel (out of, drew from single tank), engine room fire, total electrical loss, partial flooding, lack of adequate steering on a single, multiple eng/ steering failures....probably more if I sat and thought about it.

Twins can't prevent every situation, but I would definitely go twin or wing/back up engine on my next cruise. Unless I kept to a shot ICW run every year.

I would submit that a complete set of good tools, plenty of spares and the knowledge to be able to use them is an economical alternative to twins for get home capability. I have thousands of miles on singles and have never seen a complete breakdown of the type that couldn't be made to function enough to get in. This of course includes a through maintenance program and the knowledge to know when you shouldn't leave the dock. But I'm also not a fan of twins for a variety of reasons, none that I would presume to impose on anyone else.

I have seen plenty of cruise stoppers for singles not only on my boat but hundreds of others I have towed.

It's not possible to carry every spare and not everyone has the physical ability or inclination to do every repair that can stop a single engine boat....or even twins in some cases.

If you can live with what that might bring, then that's one con you can strike off the single column.

I have a single in this live aboard, and while I only have had one show stopper in 15,000 plus miles, I never had one on my last liveaboard that was a twin.

Luckily I broke down after a round trip to Forida, 15 miles from my home dock. My assistance towing boss allowed me to tow the boat to my home slip for free. The tow would have cost well over $1000 or well over $3000 to stay where I was, and have the marina repair it.

Twins aren't a magic bullet, but I do feel they give more options if you feel you need them.

sunchaser said:

Brooks
I take it you don't like twins? I was interested in " many things can take out both engines" - what are these things? Please don't say bad fuel, which has a whole host of preventative measures if put into use.

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Depending on your hull configuration, a grounding very easily could disable both drivetrains where a protected single with full skeg may come away unscathed. I know this has been covered in other threads, but you did ask.

Ted

I lost a shifter cable last year as I was setting the anchor at my favorite sturgeon fishing hole. Having a 2nd engine paid off. I enjoyed a couple of days fishing despite the failure. I manually selected fwd on the tranny lever and could start/stop the engine as needed in fwd gear. Reversing was a challenge so I avoided that except for anchor setting on one engine.

Came back into the slip single engine. Since I share the fairway with the USCG, I called ahead to ensure they didn't have any active ops that would interfere with my handicapped maneuverability. Made it in no problem.....swish!

Score one more for twins!

O C Diver said:

Depending on your hull configuration, a grounding very easily could disable both drivetrains where a protected single with full skeg may come away unscathed. I know this has been covered in other threads, but you did ask.

Ted

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You are correct, but the secret is to avoid those grounding situations whether in a single or twin.

Where we boat there are very few benign bottoms , mostly rock. Hard rock gets most of us looking around quite avidly. We've seen many grounding in the PNW over the years whether singles, twins, sailboats or tugs and barges. Most seem related to ignoring nav aides or anchoring at higher tide and then 15 feet or so gets sucked out from beneath.

When boating on the Mississippi, sand groundings were very common, heck we'd intentionally beach our party boats, big ones at that. The worst problem we had was sucking sand into the sea strainer. Ouch

Some underwater designs whether twin keels, prop pockets or low keel with higher props seems a design that is quite common for twins.

That's why I always have a spare cable taped right alongside the one in use, takes about five minutes to change and costs forty bucks.

FlyWright said:

...

Came back into the slip single engine. Since I share the fairway with the USCG, I called ahead to ensure they didn't have any active ops that would interfere with my handicapped maneuverability. Made it in no problem.....swish!

Score one more for twins!

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Score one for Commander Thach!

https://en.wikipedia.org/wiki/John_Thach

Is there any truth that some insurance companies will not insurance a single if it going from the U.S. to the Bahamas?

NewbieFromNJ said:

Is there any truth that some insurance companies will not insurance a single if it going from the U.S. to the Bahamas?

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Some might, but my ins co has no problem with my single going to the Bahamas.

Mine allows my single to the Bahamas also....

Mine has no issues with me going to the Bahamas.

Ted

I had the same concerns when I was considering switching from twins to a single. The boats over layout, build, and the applicability to the intended use are the key aspects. It so happens the things we wanted came with a single engine, so that is what we got. I was very good at close quarter maneuvers with twins on the past two boats we owned. After 8 months with a single I feel confident, but still have room for improvement. That is part of the fun..learning new skills.

Unless I hit the lottery my future boat will be 20+ years old. I think all will agree that a engine will become less dependable and more likely to break as it ages especially when it hits the 20+ age. Hence would I not be better off with twins on a older boat especially when you find yourself in those dangerous scenarios previously stated.

NewbieFromNJ said:

Unless I hit the lottery my future boat will be 20+ years old. I think all will agree that a engine will become less dependable and more likely to break as it ages especially when it hits the 20+ age. Hence would I not be better off with twins on a older boat especially when you find yourself in those dangerous scenarios previously stated.

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Depending on the engine, rebuild it. I'd rather have one rebuilt verses 2 that you consider unreliable.

Ted