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Thread: Twins to singles

  1. #1

    Twins to singles

    Hi all.
    Has anyone one here repowered from twins to a single motor.
    Interested to know your thoughts and experiences as I am about to make that decision shortly.
    Its on a vagabond with twin 90 etec either going to merc 115 ct or a single 250 merc.
    Sums suggested the 250 but my gut strings keep pulling to the 115s.

    Love some input here. Cheers

    Sent from my SM-G780F using Tapatalk

  2. #2

    Re: Twins to singles

    There's a whole bunch if stuff at play here, let's say you are going from equal single HP to equal dual HP, the single is lighter, faster, cheaper to buy and maintain. The dual setup is heavier, way more torque, more stability underway, easier docking, slower, more costly in every area, offers "some" redundancy, and above all, looks good! As an example a pair of (say) 150's will pull a single 300 backwards, but the single will be faster, make sense?

  3. #3

    Re: Twins to singles

    Not sure what you mean by redundancy.
    I guess it comes down to how much of that control am I willing to sacrifice for a cheaper ride.
    Not to mention filling holes and drill ing new ones.
    There would be a gain in transom space too i spose.
    Would like to hear from someone who has done it.
    Was there compromising or regrets.

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  4. #4
    Ausfish Addict disorderly's Avatar
    Join Date
    Sep 2006
    Location
    In the Jungle

    Re: Twins to singles

    Noel means that you have some sort of a backup if one motor fails but he rightly states "some" because its no real redundancy if it happens to be a fuel issue and your fuel has come from the same tanks or servo or an electrical/battery issue outside of the motors themselves for example........

  5. #5

    Re: Twins to singles

    I have gone both ways...(not the ways you are thinking) but not on my own boat, just did the fitting and testing, it's very much a personal thing, I like twins, but the mate I did the twins to single thing loves the boat, by redundancy I mean if one fails, you can still get home (hopefully)

  6. #6

    Re: Twins to singles

    Quote Originally Posted by Noelm View Post
    I have gone both ways...(not the ways you are thinking) but not on my own boat, just did the fitting and testing, it's very much a personal thing, I like twins, but the mate I did the twins to single thing loves the boat, by redundancy I mean if one fails, you can still get home (hopefully)
    Yep we had one motor go on us 38km from home and limped home on one.
    Fuel isn't the only thing that can happen.
    So I have partly answered my own questions.
    Except for the handling ones which is probably the biggest ones.
    So any Seafarer owners that have done this or have been in a twin rig as well as a single one I would love to hear from you. Cheers

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  7. #7

    Re: Twins to singles

    Most modern four stroke are super reliable if maintained correctly. If your boat is set up with twins that have independant systems (fuel etc) then agree 100% that if you are travelling far distances you have that safety factor built in but I dont think it is much of a consideration of they are sipping from the same cup. Maybe you could factor in some unusual electrical fault (sensor etc) on one engine occurring and having the second motor is a saviour but there is some considerable savings to be had with running the one. At sea over the last 20+ years with a single 4 banger I think I have only had one occurrence of a problem (IAC Valve) that could have stranded me but managed to get her going by using the cold start lever and getting into gear for the run home. Lots to consider V8 250 Merc - very nice !!!

  8. #8
    Ausfish Platinum Member
    Join Date
    Mar 2015
    Location
    Kalbarri, WA

    Re: Twins to singles

    I went from twin 60hp 2 strokes --Mercs, late 90's, low hours, excellent condition--on a Swiftcraft Dominator, 5.65m. To a relatively high hour s/hand F115. I lost maybe half a knot top speed, and acceleration difference was negligible. And fuel halved, of course. Twins are just a PITA on outboard power in most instances, really. Yeah, look cool, might sound cool, just more sh*t to have to juggle, particularly if conditions go bad. Double your maintenance costs, approximately as well.

  9. #9

    Re: Twins to singles

    Quote Originally Posted by stue2 View Post
    Yep we had one motor go on us 38km from home and limped home on one.
    Fuel isn't the only thing that can happen.
    So I have partly answered my own questions.
    Except for the handling ones which is probably the biggest ones.
    So any Seafarer owners that have done this or have been in a twin rig as well as a single one I would love to hear from you. Cheers

    Sent from my SM-G780F using Tapatalk
    What was it that went on the donk?
    Democracy: Simply a system that allows the 51% to steal from the other 49%.

  10. #10

    Re: Twins to singles

    What was it that went on the donk?

    Got salt water in it.
    Slowly got into the seals and gaskets and crystallised expanded the gaps until salt mist sprayed all through everything including number 1 cylinder.
    We discovered it a couple years ago and thought we had it sorted.
    And this happened even tho it was flushed every time without fail.


    Sent from my SM-G780F using Tapatalk

  11. #11

    Re: Twins to singles

    stue, if it helps as all i went from singe v6 4.2 yammy to twin 140 zukes on a deep V plate boat about 6.8. so 4.2 litres of block in single config 225 to a total of 4 litres of block for 280 in the twins. Twins are winning on fuel economy by 0.2 km per l, torque (2 props) is just as good as the yammy if knot better, and just general sea keeping is better on twins whilst the yammy was faster by a couple of knots.

    rgds, Scott

  12. #12

    Re: Twins to singles

    Quote Originally Posted by Out-Station View Post
    stue, if it helps as all i went from singe v6 4.2 yammy to twin 140 zukes on a deep V plate boat about 6.8. so 4.2 litres of block in single config 225 to a total of 4 litres of block for 280 in the twins. Twins are winning on fuel economy by 0.2 km per l, torque (2 props) is just as good as the yammy if knot better, and just general sea keeping is better on twins whilst the yammy was faster by a couple of knots.

    rgds, Scott
    Thanks for this.
    This is what I think will happen too.
    The 250 Verado will use similar fuel to twin 115 pro xs ct on paper at least.
    The only negative is the maintenance that I can think of.
    Given the Vagabond seems to require a bit of weight on the back the verado is a good fit.
    But they go very well with twins.
    Twins come with cables and crap, the verado with a wire.
    I like the idea of a big single but not sure i want to give up what the twins gave.

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  13. #13

    Re: Twins to singles

    Stue, i've never had anything to do with merc's but i recon the 4.6L v8 250 will be more thirsty that the twin 115 mercs given same net cylinders but more displacement than the 4.2L combined total in the 115's. Only reason i went my zukes over the 115 mercs was fitting gauges easily!! I recon those 115 mercs are great spec and lots of torque down low. My guess like you is that the single will be a rocket whilst the 115's will be better in all other departments (apart from the wallet!!). Good luck with it. I find that its only my travel time that i'm running the two, Pretty much all fishing, trolling etc i do on one or the other so i'm not double clocking hours for this work.

    Scott

  14. #14

    Re: Twins to singles

    Outstation, you have to take into account the single leg in the water also. My bet is the single will use less fuel.
    Democracy: Simply a system that allows the 51% to steal from the other 49%.

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