dhays
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Wow! You are changing boats every 2 1/2 years. I bet you are really good at adapting to different systems at this point.
Single or Twins?
- Thread starter maineman
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The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Wow! You are changing boats every 2 1/2 years. I bet you are really good at adapting to different systems at this point.
sunchaser
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Assuming the boats and engines have been well tended, OC made a good point. When in far away places twins may have an advantage. In the far reaches of AK a vessel with twins does indeed provide a level of security that a single without get home does not. Been there, needed that option. 
Most twins handle well when one engine is down. If per chance you are sea trialing a twin, put one in neutral and try it out.
Most twins handle well when one engine is down. If per chance you are sea trialing a twin, put one in neutral and try it out.
psneeld
Guru
And I have seen twins take out fuel docks and other boats....in benign conditions.
That is the fault of the skipper, not the boat.
The only difference in my experience...is twins are like a single with a get home engine....
It's not a safety issue 99% of the time...but a huge convenience issue or required for speed... nothing more...nothing less.
That is the fault of the skipper, not the boat.
The only difference in my experience...is twins are like a single with a get home engine....
It's not a safety issue 99% of the time...but a huge convenience issue or required for speed... nothing more...nothing less.
Nomad Willy
Guru
The biggest difference is usually a matter of power and weight. Most trawlers are built with the twin engine option having much more total power. So the question is mostly how much weight and power do you want. For many the maint and boat handling issues are minor compared to the big difference in power, fuel consumption and weight.
Egregious
Guru
Oxygen Tent. HA, never heard that before. Mine is like a sail and once the wind catches you it's all over. I've learned to use it to my advantage when possible.
access to the outside of twins really isn't a big issue. In 24 years with this boat's twin configuration I have found access to the outside of the stb engine a minor inconvenience, primarily to get the oil filter off without creating a mess, as it required a drain pan on the stringer (as does the Port engine, but that one is in the middle of the boat) and then recovery of the filled drain pan without spilling. Once I learned the right technique, no big deal. I think most of the guys who reject twins for that reason have just failed to think it through and find a better way to get that access.
I haven't ever had a problem on the outside of the port engine. I find access to the back of my outboard more difficult.
I haven't ever had a problem on the outside of the port engine. I find access to the back of my outboard more difficult.
Nomad Willy
Guru
Keith,
You could install an extractor manual pump connected w a hose and fitting at the oil pan drain hole. Then you can route the hose and manual pump wherever you want it. Shouldn't cost much.
And the oil should drain out of the filter. Some poke a hole on the top of the filter as a breather vent.
You could install an extractor manual pump connected w a hose and fitting at the oil pan drain hole. Then you can route the hose and manual pump wherever you want it. Shouldn't cost much.
And the oil should drain out of the filter. Some poke a hole on the top of the filter as a breather vent.
ER access w single is a dream...haven't been aboard a twin.
You didn't mention thrusters...if single has a thrister or two handling is easy.
Lots of support either way...goid news is you won't go wrong either way
You didn't mention thrusters...if single has a thrister or two handling is easy.
Lots of support either way...goid news is you won't go wrong either way
Eric
My oil filter gets changed annually. It takes maybe 3 minutes. Not so big a problem that I would spend any time or energy trying to solve. My system works just dandy. I mentioned it only to minimize the so called "problems with access" mentioned so frequently in the classic argument over singles v twins.
Phyrcooler
Senior Member
Agree with most of what has been said. I have the 240 hp twins in my 390. They do have a good reputation. Mine tops out 16/17 knots. I've heard performance for the newer 34 is similar. Hopefully others with a 34 will pipe in. For my SouthWest coastal cruising, I'd have been just as happy with a single. Many (most?) late model single engine Mainships already have the bow thruster. Twins do provide some security, but I'd cruise a single no problem as long as I had a switchable dual filter Racor set up and the boat was well maintained prior to departure. As others have noted, buy the best boat - twins or single unless you really want those extra knots of speed. In that case the twin wins.
Phyrcooler
Senior Member
When it is windy, we open up all the windows which lessens the impact to my docking maneuvers... some. Likewise, if running into the wind, I'll open it up and let the air blow through.
Nomad Willy
Guru
Keith wrote;
"My oil filter gets changed annually. It takes maybe 3 minutes. Not so big a problem that I would spend any time or energy trying to solve. My system works just dandy. I mentioned it only to minimize the so called "problems with access" mentioned so frequently in the classic argument over singles v twins."
I see but you have 7 gallons of oil to deal with. I can imagine why you don't change it more often.
And very good input re the "twins are difficult to deal with maint wise" syndrome. I've been wondering about that. Sometimes guys talk like if they have to bend over to work on their engine it's unacceptable. I'm sure though that there are boats that are really a PITA.
"My oil filter gets changed annually. It takes maybe 3 minutes. Not so big a problem that I would spend any time or energy trying to solve. My system works just dandy. I mentioned it only to minimize the so called "problems with access" mentioned so frequently in the classic argument over singles v twins."
I see but you have 7 gallons of oil to deal with. I can imagine why you don't change it more often.
And very good input re the "twins are difficult to deal with maint wise" syndrome. I've been wondering about that. Sometimes guys talk like if they have to bend over to work on their engine it's unacceptable. I'm sure though that there are boats that are really a PITA.
Comodave
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I am not lazy... I challenge anyone to come and enjoy changing my starboard engine impeller. There is a big difference in accessibility with twins vs single. Anything can be done on any engine. It is just a case of how hard it is or how much you are willing to pay someone to do it for you. I do like having twins until it is time to work in a cramped engine room.
BruceK
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Indeed Tom.Singles vs twins
If it keeps ever so slightly on course, one boat model with one or two, it could help the OP. Putting aside the entrenched views,hopefully, the OP is getting answers.
Hi!
Quite recently I went through the same dilemma and did a lot of day and night reading in forums and various articles, but also discussed different thoughts and views with other boaters and mechanics. My choice was to go with the single engine 370hp 6LYA-STP Yanmar powered Mainship 34T (2006).
I added a stern thruster (100Kg) to the factory installed bow thruster (80kg I believe) and new Side Power dual joysticks (2 helms), so maneuverability is not an issue anymore. The boat is actually able to spin around itself 360 degrees easily and swiftly. It's impressive! You just need to use the thrusters wisely, meaning not for more than 10-15 seconds per thrust (which is sufficient), so as to avoid damaging the electric motor. Also, have installed dedicated 200Ah batteries on each thruster to make sure there is enough power when needed, as thrusters need much electricity in a short period of time. Without the thruster there where some issues in the marina with side winds, as this is a bit of a tall boat.
I also needed to have a reliable back up system to get me to the closest shore in case the main engine fails: installed a Yamaha gasoline 9.9hp High Thrust, Extra Long on a turning inox base which is securely placed with through bolts in the middle of the swim platform (moved the swim ladder to the right, in line with the transom door). The specific large propeller Yamaha with its appropriate gearbox is indeed able to push the boat, maybe not against a strong wind/current, but it is a reliable tool to get me to safety if the Yanmar fails. The Yamaha gives me the freedom and peace of mind that I have 2 separate motors, 2 separate ignition systems (manual for the Yamaha), 2 separate fuel tanks, 2 separate propellers. For use as a coastal cruiser and for island hopping i.e. not having a huge distance from the closest shore, this set up suits me fine. Attached is a photo.
Finally, as a "free bonus gift" I get the lower maintenance costs and the lower hassle of the single engine. That has been my rationale in the very recently purchased 34T. Hope it is of some help in your buying decision process.
Happy Travels!
Paris
PS. First impressions with the 34T are excellent. We traveled the boat on it own bottom from Limassol, Cyprus to Athens, Greece, a distance of 500 n.miles and it was just so comfortable and we felt very safe. Its a very good boat, with a well thought of design and its well built. Go for it! You will enjoy it!
Quite recently I went through the same dilemma and did a lot of day and night reading in forums and various articles, but also discussed different thoughts and views with other boaters and mechanics. My choice was to go with the single engine 370hp 6LYA-STP Yanmar powered Mainship 34T (2006).
I added a stern thruster (100Kg) to the factory installed bow thruster (80kg I believe) and new Side Power dual joysticks (2 helms), so maneuverability is not an issue anymore. The boat is actually able to spin around itself 360 degrees easily and swiftly. It's impressive! You just need to use the thrusters wisely, meaning not for more than 10-15 seconds per thrust (which is sufficient), so as to avoid damaging the electric motor. Also, have installed dedicated 200Ah batteries on each thruster to make sure there is enough power when needed, as thrusters need much electricity in a short period of time. Without the thruster there where some issues in the marina with side winds, as this is a bit of a tall boat.
I also needed to have a reliable back up system to get me to the closest shore in case the main engine fails: installed a Yamaha gasoline 9.9hp High Thrust, Extra Long on a turning inox base which is securely placed with through bolts in the middle of the swim platform (moved the swim ladder to the right, in line with the transom door). The specific large propeller Yamaha with its appropriate gearbox is indeed able to push the boat, maybe not against a strong wind/current, but it is a reliable tool to get me to safety if the Yanmar fails. The Yamaha gives me the freedom and peace of mind that I have 2 separate motors, 2 separate ignition systems (manual for the Yamaha), 2 separate fuel tanks, 2 separate propellers. For use as a coastal cruiser and for island hopping i.e. not having a huge distance from the closest shore, this set up suits me fine. Attached is a photo.
Finally, as a "free bonus gift" I get the lower maintenance costs and the lower hassle of the single engine. That has been my rationale in the very recently purchased 34T. Hope it is of some help in your buying decision process.
Happy Travels!
Paris
PS. First impressions with the 34T are excellent. We traveled the boat on it own bottom from Limassol, Cyprus to Athens, Greece, a distance of 500 n.miles and it was just so comfortable and we felt very safe. Its a very good boat, with a well thought of design and its well built. Go for it! You will enjoy it!
maineman
Veteran Member
I love the idea of a little get-home outboard that could be hung off the swim deck. Maybe store it covered in the cockpit somehow and hang it on a bracket when needed. Just in case...
What sort of a tender would be needed to maneuver a boat like this? Currently, we use a 8.5 RIB with a 5 HP.
What sort of a tender would be needed to maneuver a boat like this? Currently, we use a 8.5 RIB with a 5 HP.
A little lost in this thread is the OP's intended usage.
In BC and Alaska speed isn't hugely useful except - possibly - to help with timing rapids and narrows and getting across open stretches a bit more quickly. Rough water - particularly from current against wind - result in short, steep waves that require reduced speed. And there's lots of large pieces of wood (particularly escaped logs) in the water - some of it right at the surface or even submerged - so running fast in less than flat water and perfect visibility is a gamble that experienced mariners generally avoid.
Range, however, is more useful with fuel options rather widely spaced and inconvenient.
And draft isn't generally an issue - but when there's something under the water it's probably a rock. There are a bunch of folks in my PNW YC that have struck a rock or log and damaged a prop (or worse), but I can't recall anyone hitting anything with a protected single. Then again, most of our vessels are semi-planing boats with twins so that's probably not a relevant sample.
But many, many operators have run over crab lines...or fishing nets...or backed over their dinghy painter. So many folks carry some level of diving equipment for those areas where a diver isn't on call.
Now take a look at the image in the TrawlerForum header above - does that look like "single" or "twin" territory to you?
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Nick14
Guru
FWIW, I'll throw in my 2 cents (and it'll be worth far less than that) based on my own personal experiences.
I've owned 13 boats over 45 years. 11 of them (over 40 years) have had singles, and two (over 5 years) have had twins. For most of my life, I was a die-hard single engine fan, for the ease of engine access, simplicity, and economy. I subscribed to the often-quoted belief that most engine problems are caused by fuel, and with dual fuel filters and keeping up on maintenance, most problems should be avoided.
My last boat had a single diesel engine. We bought it brand new, and in the first year, with under 100 hours on the engine, we had two failures that each left us stranded. Both were non-fuel related, and both would have been non-issues in a twin engine boat.
In one case, the main engine water pump failed suddenly and catastrophically (at 75 hours). While this might be uncommon, in a twin engine boat, it would have been no problem to get back to port.
In another case, we lost steering (a hydraulic line failure), while in a narrow, busy, crowded commercial channel with a fast-moving current. Again, with twins it would have been possible to steer and get to safety, but with one engine and no rudder control (and no time to jury-rig anything), it was a bit harrowing.
As I shop for my next boat, these experiences weigh heavily on my mind, and have me leaning to twin engines. While the problems I had may be uncommon, we're all victims of our own past experiences, and mine have caused me to rethink by former allegiance to single engines.
I've owned 13 boats over 45 years. 11 of them (over 40 years) have had singles, and two (over 5 years) have had twins. For most of my life, I was a die-hard single engine fan, for the ease of engine access, simplicity, and economy. I subscribed to the often-quoted belief that most engine problems are caused by fuel, and with dual fuel filters and keeping up on maintenance, most problems should be avoided.
My last boat had a single diesel engine. We bought it brand new, and in the first year, with under 100 hours on the engine, we had two failures that each left us stranded. Both were non-fuel related, and both would have been non-issues in a twin engine boat.
In one case, the main engine water pump failed suddenly and catastrophically (at 75 hours). While this might be uncommon, in a twin engine boat, it would have been no problem to get back to port.
In another case, we lost steering (a hydraulic line failure), while in a narrow, busy, crowded commercial channel with a fast-moving current. Again, with twins it would have been possible to steer and get to safety, but with one engine and no rudder control (and no time to jury-rig anything), it was a bit harrowing.
As I shop for my next boat, these experiences weigh heavily on my mind, and have me leaning to twin engines. While the problems I had may be uncommon, we're all victims of our own past experiences, and mine have caused me to rethink by former allegiance to single engines.
saltcod
Senior Member
Single or twins?
Well, having recently managed to wrap a crab pot line around one shaft, I'm saying twins. We would never have been able to make it home if we had single shaft. I'll admit, with a single shaft, it probably is deeper under the boat, and less likely to snag but...
As it turned out, I used pruning shears to remove much of the offending rope working from the dingy. At the end of things, I wound up diving, wearing a drysuit, on the prop/ shaft in freezing waters, with ice on the surface. It wasn't fun.
Well, having recently managed to wrap a crab pot line around one shaft, I'm saying twins. We would never have been able to make it home if we had single shaft. I'll admit, with a single shaft, it probably is deeper under the boat, and less likely to snag but...
As it turned out, I used pruning shears to remove much of the offending rope working from the dingy. At the end of things, I wound up diving, wearing a drysuit, on the prop/ shaft in freezing waters, with ice on the surface. It wasn't fun.
@OP:
As mentioned above, range is an important consideration in your case. I'd go for a single over a twin for any long range work, due to the superior fuel economy on offer.
The 6LY is a beautifully constructed engine, and there are plenty of fishermen out west who stake their lives on its reliability. The engines regularly live past 10k hours, so longevity should not be a concern. They do have an unpleasant tendency to leak oil around the sump, and fixing this is non-trivial, but it is not a reliability concern, just an annoyance.
I understand that the singles vs dual debate is a very dead horse around here, so I'll try to not get too general. There is one point I would like to highlight, though: Given a fixed budget, you'll be able to maintain a single engine to a much higher standard. Even though you don't perform the periodic maintenance yourself, servicing a tightly packed dual installation is more expensive per engine. Poor engine room access also poses an increased risk that your mechanic will skip certain maintenance points, either out of laziness or simply not noticing something because it's so well tucked away. There are some anodes in absolutely nasty locations on the above mentioned engines, so this should be kept in mind.
As mentioned above, range is an important consideration in your case. I'd go for a single over a twin for any long range work, due to the superior fuel economy on offer.
The 6LY is a beautifully constructed engine, and there are plenty of fishermen out west who stake their lives on its reliability. The engines regularly live past 10k hours, so longevity should not be a concern. They do have an unpleasant tendency to leak oil around the sump, and fixing this is non-trivial, but it is not a reliability concern, just an annoyance.
I understand that the singles vs dual debate is a very dead horse around here, so I'll try to not get too general. There is one point I would like to highlight, though: Given a fixed budget, you'll be able to maintain a single engine to a much higher standard. Even though you don't perform the periodic maintenance yourself, servicing a tightly packed dual installation is more expensive per engine. Poor engine room access also poses an increased risk that your mechanic will skip certain maintenance points, either out of laziness or simply not noticing something because it's so well tucked away. There are some anodes in absolutely nasty locations on the above mentioned engines, so this should be kept in mind.
FF
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"As it turned out, I used pruning shears to remove much of the offending rope working from the dingy. At the end of things, I wound up diving, wearing a drysuit, on the prop/ shaft in freezing waters, with ice on the surface. It wasn't fun."
Folks with existing boats usually install line cutters.
Folks working on a new build can copy what many Euro canal boats do.
There is a built in hatch above the WL directly over the prop shaft that with a tree pruning saw makes quick work of line .
Folks with existing boats usually install line cutters.
Folks working on a new build can copy what many Euro canal boats do.
There is a built in hatch above the WL directly over the prop shaft that with a tree pruning saw makes quick work of line .
This particular thread can become bit of a yawn for experienced boaters. However, somewhat of an eye opener for newbie boaters regarding inboard, straight drive-shaft boats having prop
Part of the allure to bring in new boaters [or even boating wan-ta-bees] to become participants in Trawler Forum, as well as basic responsibility of knowledgeable contributors to TF, is to over and again hash out the pros and cons of nearly unlimited various circumstances regarding all types of boats and other marine doings. Even for those of knowledge there are at times new ways/means/things/product-advances occasionally brought up for doing/accomplishing needed items in the boating and general marine sectors. To locate and stay abreast of these advances it is sometimes necessary to "yawn" one's way through thread posts. Usually a once over glance at a posts will discern if the post has any worthwhile sharing of knowledge.
Threads that are too much of a yawn for me become threads I stop visiting and/or posting to.
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Vashon_Trawler
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I like Paris' "get home" motor. I obviously have a single (Volvo MD2030). I can tell you that the thought of my lone diesel failing is always on the back of my mind when underway. I am on top of maintenance but one can never predict the rare catastrophic failure of a component. I am seriously looking into mounting a small long shaft outboard (6 HP would probably work for my boat) that would at least get me to a safe spot for a tow. The thought of having no power in the crowded ICW always worries me.
Go twin if you are a worrier like me!
Go twin if you are a worrier like me!
