Sailboat to Baby Lobster

Discussion in 'Boat Design' started by doogymon, Mar 22, 2013.

  1. doogymon
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    doogymon Junior Member

    http://sailboatdata.com/viewrecord.asp?class_id=6473

    Potential plan is to add a motor-well, wheel steering to existing rudder, a

    windscreen and helm chair on a raised sole in cabin/companionway.

    Looking for suggestions for steering system?

    Pulleys? Teleflex?

    Would a outboard motor-well work on this boat? Like to cover it up and make

    her quiet.

    Just for my Dad to putt-putt out in the harbour.

    Regards
     
  2. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    Even a small outboard will take up a lot of space moving it forward and trying to cover it. I would suggest cutting a hole in your transom 25" up from the keel and getting a long shaft outboard up to 10 HP which will push it right along. You will likley have to strengthen your transom inside with 3/4" plywood or 2-1/2" pieces of ply bonded to gether. Why not temporary mount the seat next to the engine and use the tiller handle for steering and control.
    Then if all is well you could install remote controls. An 8-10 hp will tilt forward 12" to get the prop out of the water. (11.3") to be exact plus cover and frame. You may need an exterior wedge on the outside of the transom some 14* for the engine to mount against to provide angle if transom is plumb. You could get a bunch of money and work doing this or just go simple.
     
  3. PAR
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    PAR Yacht Designer/Builder

    You will only get 6 knots at best with this fat little sailor, regardless of outboard installed. A 5 HP outboard will easily get you to this speed, with some reserve left over for chop. A 10 HP would just be more motor than you need, unless you head out in full gales and heavy seas. I'd look for the smallest electric start, long shaft outboard you can find, which will likely be in the 8 HP range.

    A 25" transom cutout will require an extra long shaft Stan, not a long shaft. This would be a good idea, as the boat will want to snatch the prop out of the water in a swell or chop. I don't think there's enough transom for an extra long shaft, so a 20" shaft may be necessary. It's ventilation plate should have a few inches of bury, to prevent it popping out.

    As to the conversion details, you can go many ways, but this is a light boat at about 1,200 pounds with a significant amount of ballast in the fin (300-400 pounds). She doesn't have a lot of capacity for a lot of additional weight, particularly if high up. You could remove the deck cap and liner and if lightly built, a doghouse/pilothouse type of enclosure can keep the big guy warm and dry.

    Stan's point about the transom angle will need to be addressed, as will a splash well, so boarding water can get trapped and drained over the side. Most outboards like to live on a 15 degree transom angle, so some wedges or a bracket will be needed. If you use a bracket, you can free up some cockpit space and you don't need a splash well either. Steering should be one of those TeleFlex units, as pulley and cable are infamous for breaking farther from shore then you can swim back to. You'll also need remote engine controls (throttle and shift), plus some gauges. You're a good boy to do this for your pop.
     
  4. rasorinc
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    rasorinc Senior Member

    To add a thought design the seat platform so that a fuel (removable) tank will fit inside it. Then find a space for the starting battery (vented) unless you are going with pull start. Some smaller engines do not offer remote controls but have tiller extensions. Here is the tohatsu site, good engines and they tell you all the deminsions + details on specs. http://www.tohatsu.com/outboards/6_4st.html Usually the 8 hp to 10 hp are the same engine tuned up or down, check the weight for this and if so the 10 offers use on another boat if much heavier.
     
  5. doogymon
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    doogymon Junior Member

    Appreciate the feedback.
    6 Kts is good. Was hoping to keep transom clean. Want to cut square hole through cockpit sole and then hull abaft the keel. Make a complete box (well) and the screw (prop) would be totally submerged. The pilot house would be canvas and pipe. The pilothouse roof could be a Bimini to keep things light. Helm chair is centre ice like a tug boat. Teleflex hooked to rudder is OK?
    http://www.flickr.com/photos/39452743@N07/8580385783/
    Cheers
     
  6. PAR
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    PAR Yacht Designer/Builder

    It's likely you'll have to drop the engine so deep, just to get it to clear the hull bottom that it's eat water fairly easily, if in an enclosed well at the aft end of the cockpit. An enclosed well also tends to choke the engine on it's own exhaust gases as well, unless carefully thought out.

    In a splash well on the transom or hanging on a tilt up bracket attached to the transom will be the easiest and cheapest methods, also with the least amount of "issues". In this location it also frees up precious cockpit space, which is modest on the Seaward you're working with.

    The sailboat rudder will likely need to be reshaped and frankly, with an outboard, you don't need or want the sailing outboard rudder. The outboard with vector steer with prop thrust, which is far more responsive than any rudder.

    Even though many small outboard are designed for tiller steering, they can be made to remote steer fairly simply. It usually involved an engine mounted bracket arm and a clamp. The cable is hung on this and dogged as required on the transom or splash well.

    If you're bent on the through the cockpit sole approach, it should be mounted as far aft as practical, with a cutout on the transom and hull bottom, so the engine can turn, be raised and the well can self ventilate. This will permit the engine to sit at an appropriate height, frees up the middle of the cockpit and it can still steer the boat, while breathing clean air.

    [​IMG]

    This is a Simmons Sea Skiff and though a bigger engine then you'll use, offers an idea of the cutout necessary to make it work right. A cover could be arranged, so the engine is enclosed.

    [​IMG]

    A better look at the well, though again much larger than you need, as this is for a 30 HP engine.
     
  7. michael pierzga
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    michael pierzga Senior Member

    When you put an engine in a well the cockpit becomes smokey. Modern engines are pretty clean so it might not be as bad as the old days.

    Perhaps have a look at one of the electric outboards. At the local sailing club many boats use the Torquedo.. http://www.torqeedo.com/ its about 5 hp and the sailors love them. lightweight , powerful and good range. A major benifit is no gas tank and no gas smell inside the boat and no exhaust in the cockpit. .

    Since you steer will the tiller the outboard can be locked...its well instalation can be small. Have a look at the race boats.... http://www.socasailboats.com/CRO_System/body_cro_system.html
     
  8. PAR
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    PAR Yacht Designer/Builder

    I disagree in that the cockpit needs to become smoky. Again, a well designed properly, will not let smoke into the cockpit, though as with any engine install, smoke can climb over the rail, back into the cockpit. The well shown above works fine and doesn't fill the cockpit with smoke, regardless of engine type. This is because the openings in the hull are large and open to the air, so smoke, which will take the least path of resistance and travels up, will mitigate out of the upper portions of the open to air areas of the well. This is especially true underway, when it's most important, so the engine doesn't have to breath it's own exhaust. Inside the boat, you'll need some vents, so she can suck air in or better yet is to install an inline blower, to force fresh, clean air into the well.

    An electric motor for power is a joke, even with the newer, more efficient versions. Lastly, having a choice between a rudder and thrust vectored steering of an outboard is a on brainer. Vectored steering is so far superior, that a rudder should be considered as only a last resort, when every other option has been discounted.

    If you wanted to go electric, I'd cut off the keel and it's ballast and replace it with a box keel, wide and deep enough to carry 10 or 12 batteries. With this setup, you'd have the capacity to actually putter around for a while, the batteries would act as ballast and you'd not have to find places in the cabin to hide them. Of course, charging up a bank of 12 batteries isn't any fun, but with some thought, a silent and clean way to go. Naturally an electric setup will cost a lot more then an outboard.
     
  9. tom28571
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    tom28571 Senior Member

    What is wrong with a 20" 5-6hp outboard on a standard lifting bracket off the stern? Simple cable steering or Teleflex will keep it simple. No need to chop up or modify the transom for such a small motor. 5-6 hp outboard is plenty for twice this weight. 10 hp worked well for a 5,000# sailboat in varied conditions.
     
  10. Tad
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    Tad Boat Designer

    Just putt-putting in the harbour may be a great application for a Torqueedo electric outboard. Can't be beat for quiet and not smoky at all.....Cut a hole through the bottom and cockpit sole just forward of the rudder, use the existing rudder for steering, leave the motor fixed. Make the well just big enough to fit the lower end of the outboard. Pull it up and hide it in the cabin when not in use, or build a simple cover.
     
  11. michael pierzga
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    michael pierzga Senior Member

    At the club the J boat sailors use them. they tell me 2 to 4 hours of hard motoring . They love them.

    Dont know the price, but if they are similar in price to a gas outboard they would be worthwhile looking at.
     
  12. doogymon
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    doogymon Junior Member

    Hi Fellas... An outboard motor siting on a ugly transom mounted bracket is like strapping a
    galvanized dairy bucket to Miss January's derriere..my dad has a common weakness. an eye for a curvaceous stern.
     
  13. tunnels

    tunnels Previous Member

    why not just go buy a second hand 17 foot power boat and be done with it . The small sail boat will look like a accident looking for some where to happen !! :(
     
  14. tom28571
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    tom28571 Senior Member

    An outboard is an honest piece of equipment. Among many others, I like them. Hiding an outboard inside the boat for appearance sake only is like strapping a corset on Miss January's derriere because it is too fat to be seen in the open.
     

  15. PAR
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    PAR Yacht Designer/Builder

    I heartily agree Tom. It so much simpler in an application like this. I also can't see why anyone would prefer to use a rudder, when an outboard is aboard. Lastly, an anemic electric, even one of the German ones that cost more than an outboard of twice their capacity, would be a desirable thing. Range is an hour out and if you're lucky you can return to the ramp. Not much of an afternoon, puttering around.
     
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