Single or Twin Screw!!

Shrew said:

Pulling up to the gas dock, I wish I had twins. Pulling away from the gas dock, I'm glad I have a single. Rolling in bad weather or a beam sea and I wish I had the extra speed of twins, however, doing maintenance, I'm glad I have a single.

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OK - that's a pretty good response!

One topic not yet discussed: Noise. I find the slight beat frequency created by twins annoying. Regardless of method of synchronizing rpm, they are never exactly the same (some computer engines are really close) and this creates a secondary noise frequency that varies.

If you want to demonstrate this on a twin, shut one engine down and run on one for a bit. Not only less noise due to one engine, but the secondary beat frequency is gone.

No doubt twins give more options regarding redundancy and maneuverability, but I prefer a well laid out single with bow thruster.

Seevee said:

Mrwesson,

Good points, but some prefer a twin, both in top shape, and I could argue for that.

Engines DO quit and I know of several that have failed on Loopers, some in very awkward spots, like a lock. Loosing one on the Ohio, with current and traffic would be more than a minor inconvenience. And there are place where SeaTow isn't available and yes, we can be over 50 miles off shore.

You don't divide your maintenance time between two engines, your just about double it. That's the price for twins.

Now, I could argue that the risk benefit of a single could be argued as they rarely quit.

Do you really need a twin? Maybe, if that's your comfort zone.

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To each their own but choosing twins over a single for maneuverability is kind of silly IMO. Yes you may need a bow thruster with the single but the trade off in economy is huge.

I may be biased because I get by with a single without a bow thruster and while I consider myself good it's always tricky backing into my spot in the river but it's made me better for it.

There are many good reasons for twins but I just don't feel like maneuverability is a strong one.. A single with a good bow thruster is just as maneuverable and i'd rather have a single with bow thruster or even stern thruster than twins without(around the docks).

How diffcult or practical is it to add a “get home” engine to a single screw assuming room in engine room?

ranger42c said:

I don't quite understand your complaint.

A decent search usually turns up the "personal opinion" or "preferences" many have already written -- over and over and over and over and over again, on popular and generally unchanging topics like this -- so the OP's results would be the same.

...Somebody might say something in a different way than they've said it 30 times previously, and the different wording could perhaps be useful... but that's kind of a reach.

Anyway, what do you see as the advantage of asking a commonly-asked question all over again? FWIW, I don't see it as a bad thing, just usually slow for my own purposes...

-Chris

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Conversely... what "disadvantages" of re-visiting already discussed topics are there... other than your own personal "aggravation" of having to once again travel down this (now boorish, to you at least) road?

Most of us haven't been here for thousands of posts. Many of us are just lurkers or visitors here before joining. There may be a hundred lurkers for every member. This is your new member base. At this time in the history of this site, and in the boating world in general, practically EVERY topic has probably been discussed ad nauseum.

So that you and others holding the same opinion are no longer bothered with such useless topics as "Single vs. Twin"... how about we just have one Forum Topic called "New Boating Technology Only"? A message below that single Forum Topic will say...

"...For any other information... do a SEARCH, dumbass...!!!" Probably in BOLD text.

The most obvious solution... if it bothers you, don't waste nary a single key-stroke.

But if responding (over and over and over again) gives someone something to do and allows them to impart knowledge and wisdom to another who legitimately requests said knowledge and wisdom, there is literally, no harm in it.

Every third new poster, it seems around here, gets the ubiquitous "do a search in the archives... this topic horse has beaten to death... get off my lawn" response within the first ten. As a newer member, I find it rude and off-putting... but YMMV.

It's seems that with modern technology there's probably room for redundant threads. If you search and pull up a ten year old thread entering the conversation with a question or comment is a bit problematic. I had this odd idea a forum was about conversation in something like real time. I still prefer single screw though, they've carried me thousands of miles.

Mark P said:

How diffcult or practical is it to add a “get home” engine to a single screw assuming room in engine room?

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I have a friend with a BHM 32 single that has a Yanmar GM20 with a 3/4" shaft and folding sailboat prop as a wing engine. I don't believe he's ever used it.

Understand that a boat pivots around a point and pushes that point as it moves. If you keep the pivot point moving toward your destination, the boat will follow, just like you intended. Read about boat handling and pivot point.


Wind and current move you like a fly on a freight train. You can find that reference too, somewhere.


Read about how a spring line alters your pivot point, keeps you from scrubbing against the dock.

Flybull said:

Conversely... what "disadvantages" of re-visiting already discussed topics are there... other than your own personal "aggravation" of having to once again travel down this (now boorish, to you at least) road?

Every third new poster, it seems around here, gets the ubiquitous "do a search in the archives... this topic horse has beaten to death... get off my lawn" response within the first ten. As a newer member, I find it rude and off-putting... but YMMV.

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I gave the wrong impression, apparently.

Didn't mean to suggest responding to questions is all that off-putting (you'll have seen I did reply to this question -- again -- too). And it's probably not reasonable to expect new members to automatically know what's been posted in the past, what search tools work best (and which one doesn't)...

I'm only surprised that some apparently don't want to also be directed to all the additional previous thoughts on a topic that would be available through a search.

-Chris

ranger42c said:

I don't quite understand your complaint.

A decent search usually turns up the "personal opinion" or "preferences" many have already written -- over and over and over and over and over again, on popular and generally unchanging topics like this -- so the OP's results would be the same.

Might be different if the query is about some kind of new/emerging technology or maybe a topic that's in flux for some other reason... but generally discussions about the pros and cons of singles/twins, anchors, and a few others, probably aren't gonna surface much if any new factoids, opinions, preferences... Somebody might say something in a different way than they've said it 30 times previously, and the different wording could perhaps be useful... but that's kind of a reach.

"Decent search" usually means using the Google or at least the Advanced versions, given the site's base search tool isn't great. And many new users don't know the base tool is so limited, so they don't always find much if that's the only tool they've tried...

Anyway, what do you see as the advantage of asking a commonly-asked question all over again? FWIW, I don't see it as a bad thing, just usually slow for my own purposes...

-Chris

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Read post 29.

I found this Forum by doing an extensive and exhaustive online search for more information on "Trojan F44 Motoryacht" and spent literally months reading every thread on every sight that I could find.

I don't have a trawler, nor do I want one at this particular time although I LOVE them... but 98% of "boat ****" transfers across types, and I'm a knowledge junkie.

Point is... for the general health and longevity of this (or any) Forum, it is actually much bettter to have "new blood" coming in asking the same old questions to keep this thing kicking, else this will go the way of the "VHS vs. BETA FORUM"... Not to mention the fact that new threads on old topics have different/more participants, and you never know when it is discovered that those previous discussions did NOT, in fact, know it all.

I appreciate your response above, ranger42c, makes sense to me.

BTW... I'm not fragile nor do I need a safe space... but some lurkers/new members may decide to just not participate and go away based on those responses.

NewbieFromNJ said:

Read post 29.

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??

-Chris

ranger42c said:

I don't quite understand your complaint.

A decent search usually turns up the "personal opinion" or "preferences" many have already written -- over and over and over and over and over again, on popular and generally unchanging topics like this -- so the OP's results would be the same.

Might be different if the query is about some kind of new/emerging technology or maybe a topic that's in flux for some other reason... but generally discussions about the pros and cons of singles/twins, anchors, and a few others, probably aren't gonna surface much if any new factoids, opinions, preferences... Somebody might say something in a different way than they've said it 30 times previously, and the different wording could perhaps be useful... but that's kind of a reach.

"Decent search" usually means using the Google or at least the Advanced versions, given the site's base search tool isn't great. And many new users don't know the base tool is so limited, so they don't always find much if that's the only tool they've tried...

Anyway, what do you see as the advantage of asking a commonly-asked question all over again? FWIW, I don't see it as a bad thing, just usually slow for my own purposes...

-Chris

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No need to tell them to search. If you think another thread better describes it, just copy the thread.

Nothing wrong with repeating, new blood, different times, different views.

But nothing wrong with suggesting a search so maybe a general question an be narrowed down.

Some repetative questions are so general it takes pages of replies till the real question and answers surface. And how many times does it take forever, if ever, for the OP to rejoin the discussion?

I always search before posting a question, and about half the time I find my answer and if not, usually can fine tune the question.

So sure, nothing wrong with repetative questions, but nothing wrong with suggesting a search first either.

Flybull said:

Conversely... what "disadvantages" of re-visiting already discussed topics are there... other than your own personal "aggravation" of having to once again travel down this (now boorish, to you at least) road?

Most of us haven't been here for thousands of posts. Many of us are just lurkers or visitors here before joining. There may be a hundred lurkers for every member. This is your new member base. At this time in the history of this site, and in the boating world in general, practically EVERY topic has probably been discussed ad nauseum.

So that you and others holding the same opinion are no longer bothered with such useless topics as "Single vs. Twin"... how about we just have one Forum Topic called "New Boating Technology Only"? A message below that single Forum Topic will say...

"...For any other information... do a SEARCH, dumbass...!!!" Probably in BOLD text.

The most obvious solution... if it bothers you, don't waste nary a single key-stroke.

But if responding (over and over and over again) gives someone something to do and allows them to impart knowledge and wisdom to another who legitimately requests said knowledge and wisdom, there is literally, no harm in it.

Every third new poster, it seems around here, gets the ubiquitous "do a search in the archives... this topic horse has beaten to death... get off my lawn" response within the first ten. As a newer member, I find it rude and off-putting... but YMMV.

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^^^^^^^EXACTLY^^^^^

I'm sure that if someone is savvy enough to get on the forum they are aware of what the search button does. I see a lot of impolite replies on here almost always directed at those with only a few posts from those with many. Whether or not it is intended to demean the poster, one can only speculate, but I have to wonder if they are to trying to compensate for some personal shortcoming...
It's the same as if I went into the supermarket & asked the clerk where mayonnaise is, only to have them tell me "Geez why don't you search for it? I get asked that question every day! Stop beating a dead horse!" I would consider that rude,too.

At the risk of trying to get this thread back on track. Everyone has to give a little.

-> Asking a commonly asked question can be interpreted as "I could look it up, but I'd rather ask instead".

-> This then gets perceived as "If you can't invest enough energy to look, why should I invest the energy to re-draft content for you".

-> Such a response, or a reply such as "Do a Search" then gets interpreted as "I have the answer, but I couldn't be bothered to take the time to discuss something so mundane".

.....the downward spiral continues.

----------------------------------

Let's first admit that Searches don't always return gems.

Let's also admit that, like this thread, threads get hijacked, sidetracked and derailed with cross-talk.

Let's assume that most forum questions or answers are very watered down versions of a much deeper, yet unexpressed question that isn't as easily answered as assumed.

There are benefits to any discussion. As with the reference to post #29, where it was described that twins allowed the poster to tractor home following a steering failure. Such a hidden gem can be found in post archives or a new post. Newer technologies might present a solution where there was not one previously.

Active discussions through posts is the heart of a 'social' media site such as a forum.

If the discussion is mundane, then ignore it. If the answer is so readily available, then provide it?

Apart from just searching, the only way anyone will know there are previous threads covering the ground is if someone tells them. But, how they are told can be an issue, if it starts with a "yawn", it`s not a good start. It`s not inclusive,and imports a criticism for reasonably not knowing what is not known to the inquiring member.
Not every member has the same concerns or thoughts. I knew it, but I don`t think I have seen "twins can substitute for failed steering" articulated before.
Opting for a single I think thrusters both ends are a good idea. That will be pooh pooed by expert single engine handlers,but for us mere mortals I think they are worth having,makes it easier to dock either side, etc etc.

Sorry I stirred the pot

I find this forum very helpful with lots of knowledge and thank you who took the time to respond. I did do a search and to be a blunt as some of the responses here, the search feature of this forum sucks. No matter how I asked the question all I got back was streams of off topic info.
I am in the market for a trawler and the size for our needs seems to be 36 to 40 feet. Info provided here revealed that most but not all 36' boats are single screw. Did not know that so our options are limited.

I am a DYI kind of guy and maintenance access for a twin in a 36' is tuff for a guy in his 60's with bad knees and failing eyesight. I did look at a 41 Californian and was most impressed by the engine room. You could have a dance in there

Other feedback from a PNW boater regarding tide and current is valuable information thank you. Tide and Current with several local passes to traverse and Sandheads to deal with is a serious concern getting two foot ittus already.

Cheers

PS In the future I will try not to ask too many stupid questions as rest assured I will do a search and read all of the threads before I ask

Somewhere there is guidance on how to Google search that gets much better results than the forum search feature.

My neanderthal version is to use Google, type my search topic followed by trawler forum and that works pretty well.

FlyWright said:

I prefer the redundancy and maneuverability of twins but it depends on each boat.
You've got to be able to reach the essential maintenance items on each engine. I've seen a single with an ER the size of a large tuna can. My twins are sitting in a 12'x20' ER.

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Al - Photos??? Please!!!

Ski in NC said:

One topic not yet discussed: Noise. I find the slight beat frequency created by twins annoying. Regardless of method of synchronizing rpm, they are never exactly the same (some computer engines are really close) and this creates a secondary noise frequency that varies.

If you want to demonstrate this on a twin, shut one engine down and run on one for a bit. Not only less noise due to one engine, but the secondary beat frequency is gone.

No doubt twins give more options regarding redundancy and maneuverability, but I prefer a well laid out single with bow thruster.

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Ski... That's interesting. I love hearing/experiencing the harmonics of twins. Playing ear-harmonic game of getting near perfect synchronization is a favorite of mine while getting boat onto a desired speed.

So do you use two search engines or one?

Shrew said:

At the risk of trying to get this thread back on track. Everyone has to give a little.

-> Asking a commonly asked question can be interpreted as "I could look it up, but I'd rather ask instead".

-> This then gets perceived as "If you can't invest enough energy to look, why should I invest the energy to re-draft content for you".

-> Such a response, or a reply such as "Do a Search" then gets interpreted as "I have the answer, but I couldn't be bothered to take the time to discuss something so mundane".

.....the downward spiral continues.

----------------------------------

Let's first admit that Searches don't always return gems.

Let's also admit that, like this thread, threads get hijacked, sidetracked and derailed with cross-talk.

Let's assume that most forum questions or answers are very watered down versions of a much deeper, yet unexpressed question that isn't as easily answered as assumed.

There are benefits to any discussion. As with the reference to post #29, where it was described that twins allowed the poster to tractor home following a steering failure. Such a hidden gem can be found in post archives or a new post. Newer technologies might present a solution where there was not one previously.

Active discussions through posts is the heart of a 'social' media site such as a forum.

If the discussion is mundane, then ignore it. If the answer is so readily available, then provide it?

Click to expand...

or- as Hillary once said "What difference does it make? At this point? " lol and-- as John Maynard Keyes once said, responding to an economic argument in which his opponent said--- 'In the end-------' Keyes said "In the end we are all dead."

Halifax Jack said:

Sorry I stirred the pot

I did do a search and to be a blunt as some of the responses here, the search feature of this forum sucks. No matter how I asked the question all I got back was streams of off topic info.

PS In the future I will try not to ask too many stupid questions as rest assured I will do a search and read all of the threads before I ask

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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

otis maximus said:

So do you use two search engines or one?

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Cracked me up!

-Chris

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.

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

I’ll add one more point in the single/twin debate which I haven’t seen mentioned yet.

When shopping for my boat I had a limited budget and was mostly looking at 30+ year old boats with questionable engines. At first I thought twins would be a good idea as one would surely fail, and there is no tow service available.
My thoughts changed to why buy two old engines that will likely need rebuilding or replacing during my ownership. So I bought a boat with a single and a sail backup.

Sure enough, the old Volvo gave up on me (luckily at the dock) and I replaced only the one engine.

When we were searching for our boat I wanted a single, but the boat we both loved had twins - so we have twins. No big deal.

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.