Alex's 'Phinn'

Has anyone had a go at building a footy derived from Alex Austin’s entry in the MYA design competition last year? I was attracted to it when I first saw it, partly because the hull form reminds me of the 19th century models to the ‘1730’ Tonnage Rule. It seemed appropriate for me as a historian of model yachting. It’s also miles away from any of the other designs that we are being offered elsewhere, whether as performancew boats or as nice scalish cruisers.

I have made a start, using 0.8 mm ply for the hull sides. There are some problems in getting the hull to take a truly symmetrical form, becaue there is a ‘set’ in the ply. This looks as though it can be sorted by stuffing something down the hull to pop the side that persists in taking a concave shape. More when I have actually got the pieces together permanently and taken some photos.

Russell

Keep us posted. I’m curious about a full keel design for Footys. A few folks have talked about building classic 12 meter type hulls but I don’t know of anyone that’s sailed one.

Would slipping in the battery pack be enough to hold the hull in shape?

The battery was exactly what I used, but I eventually want to get lead at the bottom of the hull with the battery on top of it.

Currently in a re-think phase as the hull sides refused to stay taped together long enough for the West epoxy to go off. I need to think through the construction sequence again and probably use stickier tape. Paper masking tape looked OK, but managed to come unstuck overnight leving most of the joints open.

Russell

If you are using West System tm. epoxy maybe try using their 5 min epoxy to tack the joints together before doing a final seal with the regular system. I used it on a similar bending and gluing job on a thin ply Footy, it worked. Paul.

Have you thought of using a glue gun and ‘hot glue’. It’s messy but removeable, adjustable and sets very fast.

Thanks for the suggestions, which I read after I had had another go, using parcel tape to hold it all together and 5 minute epoxy filled with microballoons as the adhesive. I just did the rear joint down what will be the sternpost and it works, probably well enough to avoid the need for any further filletting with WEST.

More to the point, taping the joint onto a flat surface as well as together, has produced a straight sternpost, rather than the elegant hook at the bottom that appeared when I first made my trial taping up. The hull also looks a lot nearer to truly symmetrical, so I’m making progress.

Russell

sounds like a cool build… and a really neat concept!!!:zbeer:

Plywood twist- were these handed panels? if not, this could be the problem.
Ply is rarely flat, or bends evenly, you need to work with the twist. I tape the panels together flat, then push the deck out to shape. Use super glue to ‘spot weld’ before applying epoxy fillets.

Some years ago I had weed problems on a calm pond and saw a photo of Cliff Daniels’ ‘Prismatic’ R6m -said to be good in calms and weed- so I built a small one. A single sheet of plywood gave a 23” - 584mm hull giving a displacement of 2497gms or 5.5 lbs (I later fitted a new rig and reduced the ballast, a mistake ! heavy is good)
This made a simple boat with a canoe stern, internal ballast, and the skeg just glued straight on to the hull, an ideal beginners model? or so I hoped.
It sailed amazingly well, until I raced on a larger pond and found it sailed in a slight curve to port, as the skeg was a tiny bit off the vertical. Then as the wind got up and it heeled even further, most of the grip went and the leeway angle opened up to ~30 deg or so. Back to the drawing board.

http://www.southwold.ws/smyc/2003/photos.php?count=10

The next version is shown on the sketch, the canoe stern is replaced by a transom to make the skeg easier to fit straight. I should fit an end plate to help the grip in strong winds. This is 300mm long and fits in to a coat pocket.

The boats sail well in light conditions (and laughs at weed), having good momentum, surprisingly little wetted surface area and low form resistance. For a heavy boat -DLR 678 - it makes very little wake and just cuts through the water. The ’plank on edge’ hull is, I suppose an simple form of the low drag ’submerged buoyancy’ style of design so popular these days with ferries etc.

They can point high in good conditions ~ split 90°tack, if sailing fast and upright (less than 45 deg heel).
In strong winds they heel a lot ~70 - 80 deg and loose grip, much leeway, they will reach well, but won’t point. I feel most side force comes from the immersed deck… Bow burying, even in gales is not a problem, with all that flare and overhang.

With no initial stability, carrying sail is a problem. Ghosting sail is ~ 460 cm sq, giving a SA.DT of 9 ! and the storm sail is about half that.
The ballast ratio is 85% and should be higher. I would make a lighter rig and try for a lighter hull, or add freeboard and more ballast. An end plate would help.

They were a lot of fun to sail but frustrating in winds. Radio could help, along with some sort of wing on hull and rudder and Brett’s rig.
These are very wet boats , about as close to a submarine as a yacht, so look after the radio .

I replaced this boat with a traditional long keel yacht still good in weed and light winds but having the stability the Prism lacked. Unfortunately it’s just too long for a Footy and needs to be reworked.
For traditionalists the Footy works out as a 1/4 rater, far more elegant in my view.

I don’t know how much of this is relevant, but I look forward to seeing Phin sail and fancy building one myself.

Ian

Thanks for your contribution. Progress is at the ‘stop’ phase at present, but I have got the hull ballasted and the radio installation ready. I’m going to use a variant of Rogers radio hatch design for his Bug. I hear what you say about the need to keep the radio dry. The general form of the boat suggests that like the 1730 Tonnage Rule boats she will sail like a half tide rock, though there is a fair amount of freeboard.

I managed to get 1 Kg of lead in without bringing her quite down to her lines and the ballast ratio looks like about 77%. Shortly I hope to gear up to my normal construction speed of dead slow and get some more done. Possibly over Christmas, which even when you’ve been retired as long as I have, always looks like a good stretch of free time to get things done.

Russell

See the ‘Footying radically’ thread above.
Rod