I think this is an improvement on the original concept in that it provides for the first time a way of mounting the board which looks mechanically credible, ie could actually be removeable, firm while in place – and with a limited ability to fold back in the event of striking something. As you say, “half way” between a dagger board and a swinging board. (I guess it is held in the vertical position by a “weak link” (breakable dowel peg))?

A dagger board right at the bow, which is what this essentially is, might perhaps need to be able to break out of the slot in the manner you have drawn. I take it there is some sacrificial component pinning it in place?  (Maybe a bungy would be better than carrying a bag full of replacement dowels). Otherwise the bow transom would need to be good and strong to absorb the impact of the leveraged board hitting the bottom, the dinghy and contents having potentially quite a lot of momentum. I still don't like it much. As David points out, it is an inherently directionally unstable configuration - you won't have time to tie your shoelaces with this one, in fact I'd be inclined to leave my shoes ashore.

We have to ask why a tender should be sailed at all. In my experience it is mainly for fun, will take place mainly in the sheltered waters of an anchorage, often involving children, and where  I live, almost certainly off a gently shelving beach. A dagger board on such a tiny dinghy perhaps makes more sense than a swinging board – both have their merits - but there is no way I would put it in the bow even if it proved possible to sail with it in that position. I leave that to you, in your beautiful sailing grounds.

Arne wrote: “…and the board itself could be fitted and removed from the safety of the fore thwart”.

I think I would remove the word “safety”, as an adult kneeling on the forward thwart of a lightly constructed 8’ pram dinghy is going to have an interesting effect on the trim if there are no other occupants. If caught in a squall and a bit of a chop, at the head of a bay, you’d want to be careful doing that. Don't forget the clutter of the mast and sail right up there as well, and all that needs to be negotiated while retrieving the board and bringing it into the dinghy, in the event of needing to revert to rowing.

I return to my original question “why?” and have now convinced myself that if the dinghy were mine I would simply give it a little bit of fixed draft, by way of a deadwood keel from the forefoot to amidships. Then a pair of matching (depth) skegs aft, as I agree this is best if you are dragging the dinghy down a concrete boat ramp. 

(If it were lightly and nicely built, like Annie’s FanTan, I think I would rather carry it on my back like a turtle, which is easy and often done here.)

With the amount of rocker you have, an increase of 50mm in the draft full length would probably be enough to sail to windward, and it would sit nice and flat on a trailer or upright on a roof rack too. And maybe it would row better too? (I am not sure.)

Anyway - I am sure I am not alone in awaiting with considerable interest (and a certain amount of anticipation) the results of your trials with the bow board. Your willingness to push the boundaries is admirable. I am sure the Wright Brothers were given as much skepticism from the sideline.

Thanks, David,
Bic must have beefed up the design since I bought mine for Malena. That makes sense, as mine felt rather 'thin'...
Arne

David,
and then there is the 7’ (18kg?) Bic Sportyak. I had one for several years, and liked it. It could carry two not too big persons and rowed well enough. I kept it on deck for longer trips, and towed it behind when inshore. It eventually fell apart  -  the bottom was rather thin...

Arne

Thank you all for good and sensible comments to the Halibut design. As expected, the focus appears to be on the bowboard’s suitability, or lack of it.

I’ll try to answer the best I can, but first of all; my main focus on Halibut has been on making a well-behaved and safe rowing tender which is not too difficult to build (read: not impossible for me...). Sailing the thing has second priority  -  I already have a good sailboat, thank you.

Bow-board and sailing characteristics:
I don’t know how well it will perform, but I know it has been used, so for short-term use, I think it is worth a try. There is no way I will have a cb. in the cockpit.
Tracking will of course be non-existent with the board down. However, two of my five boats (Broremann and Frøken Sørensen, FS) were directionally unstable. If I let the tiller go to retie a shoelace or something, we would be heading in a completely different direction when I looked up again. That is why I made the tiller brake for them. With tiller locked, they behaved well. Both FS and Broremann could sail long stretches with the tiller locked. The fact that the Yorkshire coble was towed backwards was only natural, as they were to be hauled ashore stern first anyway, and the flaring transom would not scoop any water under tow.

As for the board to be awkward to set and retrieve over the bow; I see that one. For a bigger boat, I have drawn a version which can be swung up by the pull of a line, but there is no room that on Halibut. Time will show if it is practical or not, but remember, Halibut is a pram with plenty of beam, freeboard and volume in the bow area, so there is a good chance it may be doable. I reckon that the board and rig will not be erected for sailing in harsh conditions, anyway.

The size
of the shown board and rudder may be a bit over the top. I will have a closer look at the Optimist dinghy before settling on the size.

Plan B:
In any case, if the bowboard fails to be practical in use, or if it performs badly, there are simple alternatives available; either leeboards or a single daggerboard, fitted at the outside of the boat, like on some Puddle Duck Racers.

Finally,
the waters we do our boating in are not the same. In my area there is generally plenty of water underneath us until about 3-5 boatlengths from shore.

Yes, and remember  - 
my ‘client’ is myself! To me it is better (more fun) to try and then perhaps fail than not to try at all. Common sense must not become too common...

Arne                                                                   

PS to Graeme:
Twin skegs.
These are meant for my own use. Our tenders live ashore in the harbour and are dragged up and down the concrete ramp. Twin skegs (with irons on) will act as runners and let us rumble up and down the ramp without hurting the tenders.

Fixed keel.
A fixed, shallow and long keel could easily be a Plan C  -  easy enough to fit later.

Imagine, if you will, that you have a bow and arrow, and attempt to shoot the arrow the wrong way around, feathers-first. It will immediately try to turn itself through 180˚. As far as I can see, one could not let go of Halibut's tiller for more than a microsecond before it tries to do the same.

A long time ago, I sailed in Yorkshire Cobles, the fishing boat that has a deep fine bow and a deep rudder. They are excellent for their original task of working off surf beaches, but a bit tricky to handle. They have to be towed stern-first, because the deep bow makes them directionally unstable without the rudder's control.

I believe that Halibut isn't going to be a practical yacht's tender in that configuration. Just imagine launching off a beach into a bit of a sea, then leaning over the bow of a very small dinghy to rig a bow board, thus putting one's weight so far forward that the boat becomes unsteady laterally, and starts to take wavetops over the bow. I shudder.

No, the leeboard or bilgeboard is the right choice for a boat that is rowed most of the time. A centreboard or central daggerboard is not good in a boat of this size, unless a solution can be found to stop water slopping up out of the top of the case, to the great discomfiture of the rower.