AD by David Webb

09 May 2021 09:08 | Anonymous member (Administrator)
She was originally built from a design sketch, that I no longer have, as a tender for Arcadian in her original form as Spirit of the Deep. She was designed as a "maximum" 8 footer to carry charter guests and stores to the boat and handle up to a 5 horsepower outboard motor She served well in that capacity, firstly as a rowing tender when she took two or three people and a lot of stores, and once even five people! I later converted her into a sailing dinghy and that is the version I have drawn up, but with a junk rig rather than the balanced lugsail she originally had. She is still serving the new owner of Arcadian in that respect and he is very happy with her performance both as a tender and as a sailing dinghy. He says he has taught a lot of people how to sail using her.

I have called her AD (Arcadian's dinghy) to differentiate her from my other submissions.

I hope that you like her as much as I do.


  • 22 May 2021 02:49 | Anonymous member
    Dave tells me this dinghy is a bit like Slieve’s KISS, in that it is lofted from all straight lines.

    In that case, I will compare the two.

    For some reason, this straight-line type of lofting geometry appeals to me.
    The resemblance between the two ends there, however.

    KISS is a delicate little pram – this AD is a load carrier, and looks it.

    KISS has a flat bottom – this AD has a little deadrise forward, at the expense of a split in the ply and an extra join to make with epoxy fillet. The vee runs into a sight curve on the bottom, at the midship section. It is probably the better boat for it – and not all that difficult to achieve, I suppose.

    The bow and stern transoms are flared at a different angle from the midship section, meaning the inside planking needs a slight twist, rather than the straight lay which is all that is required of KISS. Again, possibly slightly the better dinghy for it, and not really much of a complication.

    (I might point out here, a slight weakness of KISS is the she has perhaps not quite enough rocker, and this trick of altering the angles of the bow and stern transoms is what allows an adjustment in the amount of rocker. I wouldn’t change it though. AD doesn’t have much rocker either, though she does have a finer entry – but AD is a load-carrier so we can’t be too worried about the transom dragging a little).

    Same as some of the other commentators, I like the Tee-shaped thwart/rowing bench and the way it can be incorporated into the structure supporting centreboard case and mast support – and this is the one-and-only change I would make to KISS.

    At the end of the day, an 8’ dink is an 8’ dink, too small anyway except as a tender, and I doubt if there will be much difference when it comes to rowing and sailing. AD has greater load-carrying ability and might be a little more weatherly under sail than KISS. At the expense of a few extra complications in the build, greater weight and more materials required – she’s a bigger boat.

    All three of Dave’s dinghies have that forward raking centreboard – perhaps eventually we will get to find out why. At least this one’s got a kick-up rudder.

    Actually, I prefer KISS much more, because, well, she’s KISS – with her slightly canard body shape, just seeming to arise so naturally from her utter simplicity.

    AD might be the better tender – but not quite so simple and nowhere near as pretty.

    You pays your money and you takes your choice.
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  • 22 May 2021 10:32 | Anonymous member
    Graeme, a couple of corrections. The rake on the bow and stern transom means that the flare is constant but the bow transom comes out as a parallel-sided piece, and the stern transom also looks different from the midship section.
    The forwars sloping daggerboard has two differences from an aft sloping one. The first is that when going to windward the daggerboars turns up to windward and if the case is loose gives an angle of attack that pushes the boat to windward, usually completely cancelling leeway and sometimes even a bit more than that. The second is that if you run aground with it, the grounding pushes the centerboard up the slot rather than tripping the dinghy up. If the daggerboard is held by a bungee cord then it just returns to its normal position when you get off the mud. The board is also much easier for the helmsman to adjust than an aft-sloping one. There is one disadvantage, the slot tends to scoop up water, especially when towed, so it needs a good seal at the thwart to prevent this. When being towed a plug in the bottom of the slot is the best solution. The difference in sailing performance with a forward sloping daggerboard is quite noticeable.
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