double-handed hiking dinghy - Big Merlin Rocket?

Discussion in 'Boat Design' started by George T, Nov 20, 2025.

  1. George T
    Joined: Nov 2019
    Posts: 23
    Likes: 1, Points: 3
    Location: Portsmouth

    George T Junior Member

    Morning all,

    I'm currently frustrated in my search for a good double-handed hiking dinghy (no trapezes) for larger sailors. For context, both helm and crew are large enough to sail a Finn with no issues an approx 6'0" and 115 kg each. Currently it's just a thought excercise but any comments on my latest idea are welcome and images attached.

    The dinghy is approx 17ft long and maybe 7/8ft wide at the gunwhales, but considerably narrower at the waterline. Sail plan is a fat head battened main at approx 10 to 12 sqm plus genoa (or possibly jib and jibboom) with an assym for downwind. Carbon rig and dyneema standing rigging. Getting the boat built is not an issue, but to what design is the big question. build material would be GRP plus some plywood where needed. Dinghy will be raced on a mix of water in the UK under a PY, mostly coast and wind average about 14-18knts.

    alternatively, if anyone knows of any designs or current production boats that would suit better, please let me know. thanks

    (ignore centreboard and rudder placement, just for show on the file drawing) aft.PNG aft.PNG bottom.PNG bow.PNG lines aft.PNG lines hull.PNG lines plan 1.PNG lines.PNG perspective.PNG plan 3.PNG port.PNG top.PNG
     
  2. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    You have shown some particularly "fat" boats. If you wish to concentrate only on boats to operate in brisk or brutal winds, then the wide ones are probably the way to go. But they may very well be dogs in light to moderate air. A good 17 +/- foot boat that will go well in variable airs is something like the Thistle. Thistles are, according to class rule, a three crew boat. With a modified rig, two can handle it very well. There are numerous other proven boats in that category, inventing a new one is of questionable value.
     
    bajansailor likes this.
  3. wet feet
    Joined: Nov 2004
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    Location: East Anglia,England

    wet feet Senior Member

    I don't think you should skip past the notion of actually building the boat quite so rapidly.That rapidly sharpening chine would be extremely challenging to build in wood and if you are contemplating a moulded composite hull,possibly incorporating the fashionable black fibres,a mould of some sort will have to be made and the considerable effort of achieving a respectable finish will be required.I would also suggest thinking through the process of attaching the deck to the hull and perhaps providing us with a sketch showing what you have in mind.

    From a design point of view,it puzzles me that you think it will be necessary for two large sailors to have a hull that is a foot and a half wider than a 505 in what are given as quite modest wind speeds.They are also known to be quite able performers in that wind range,but for large sailors the low boom can be a bit of a challenge.Having said that,one world champion crew of the not too distant past was 6'8" and he managed.You might also consider taking a look at the current GRP National 18 hull as a basis for a custom deck layout and rig as you would probably be sailing a lot sooner.
     
  4. clmanges
    Joined: Jul 2008
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    Location: Ohio

    clmanges Senior Member

    Have you thought about an Oz Goose?
     
  5. wet feet
    Joined: Nov 2004
    Posts: 1,839
    Likes: 620, Points: 113, Legacy Rep: 124
    Location: East Anglia,England

    wet feet Senior Member

    I don't think our enquirer would have done the considerable amount of work to create the boat in post #1 if he didn't already have a fairly settled idea of the type of boat he is aiming for.For those who aren't familiar with the Merlin-Rocket,it is a sophisticated racing dinghy class that has developed over almost eighty years and can be seen here: Merlin Rocket Owners Association https://www.merlinrocket.co.uk/ .

    You can see the pronounced flare in this image.
    [​IMG]
     
  6. TS19
    Joined: Nov 2025
    Posts: 44
    Likes: 4, Points: 8
    Location: Germany

    TS19 Junior Member

    Hi George,

    I would like to think along as I am in a somewhat similar situation :)

    Could you tell us more about your background, please?

    - What are you trying to achieve differently compared to say a VX One, a National 18 and an RS Venture which all seem to be suited to your combined crew weight?

    - What is your level of boat handling skills, e.g. what other dinghies are you comfortable with in the conditions you envision?

    - What is your level of agility, maybe also in relation to dinghies you have liked/disliked?

    - Are there any limitations for your design, e.g. maximum length/width for storage?

    - Are you targeting a certain performance level, e.g. relative to other dinghy designs or a Yardstick number?

    Some questions to your design:

    - What is your waterline width and draft?

    - What hull weight/sailing-ready weight/all up weight with crew did you envision?

    - What aspects are you trying to achieve with this somewhat "extreme" underwater shape?

    Thank you!
     

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