Alternative to marvelous Buccaneer 24

Now here's a design change process that is actually meaningful... the boat is under construction and the designer has freshened-up his take as he works. The most perfect of worlds netting real results.

Inspired work Baigent.

 

=====================
Gary, I'd like to try to understand the logic on your J-foils. Seems to me that doing it the way you show in the illustration that the center of lift of the foil is closer to the CB of the main hull than it would be if you angled the whole assembly just the opposite way. That would generate more RM(15-20% more, I think) for the same area. Can you help me understand your thinking?

The increase in the sketch is 17%.....

 

Interesting that you should suggest that outfacing system Doug ... because I did a similar thing earlier with Groucho although they were straight angled foils with a tip turned back towards the main hull (see jpeg with the foils lifted) ..... and there was nothing wrong with them except that theoretically there was a force upwards and to LEEWARD while beating ... which worried me, hence the tips and the dagger in the main hull. But anyway the boat was excellent to windward and the foils did the job of lifting. Plus you get a greater righting moment because the overall platform beam is wider. BUT you have to be careful rounding marks or anchored boats because it is easy to pick up warps ... and then there is some slight embarrassment. The boat is very wide to start with and outward facing underwater foils can enhance Sod's Law. So I'm being more conventional with Sid!

 

got any updates Gary?

 

Ah, Captain, have been busy doing other things, like repairing and painting Groucho's broken wing mast and erecting it, plus various other little jobs ... and sailing ... because aside from a couple of recent cyclones (and an enormous tide) the Auckland weather has been superb.

 

Instead of the double section, full hard wing, I'm drawing up plans for a double luff, soft sail, double battened main on a 12 metre tall x 1 m chord x 220mm thick wing spar; the double luff is 170mm wide and the sail 1.5 m from foot to hounds area where it tapers to square topped peak, giving me a total of around 29 m2 area - this for 7.6m Seditious Sid. I'd post a jpeg but my digital camera has failed; my fault, tried to clean the sensor, which has fungus on it (Auckland climate!) and the shutter closed on the cleaning stick, merde!
The main spar (roughly half the total sail area) will be 3mm klinki, plus uni carbon, with cut away frames every metre, no I beam, because the chopped off after section becomes the I, makes it a box, so to speak. With a double luff, I can hide the down facing vang between the sails ... that means no semi circular main sheet track and highly loaded main sheet systems. The big deal is that although the main spar is a metre chord, the boat will be able to live with that on a mooring? ... but the full wing, because of the double luff, will be able to be REEFED.

 

----------------
Gary, this sounds very interesting! What would you think if the rig was used on a boat that could capsize-would the space between the double luffs drain quick enough to right?

 

Doug, the main spar would provide a large volume of buoyancy, for awhile, until the water seeped in through the halyard exits but I doubt if the platform would ever go right over, mast intact, that is - but the double luffed sail area at the peak will have a capped area of sail cloth plus a bendy central support batten, so it would also be slow to fill. The double sail trailing edges will be sown, and the base tack and clew will be attached to a base end plate, so that area will be open ... so water could enter from the top but not rapidly. You'd need a knife to slash the leach area to dump water.

 

"A few questions about Sid
Good day Gary

I really love the shape of Sid and i think your building method is interesting.
I wonder if you possibly could describe your building method of Sid a little closer, either here or in your post about Sid. Do you make rough ply panels that you glue to the strongback and then cut them off at the precise deck level when they are in place?

Did you glue the ply side together before attaching them to the strongback?

Thank you."

hi Brorsan,
My building method is really very old school and based sort of on Hugo Myers (and others) methods when he built his beautiful, radical, 44 foot Seabird catamaran back in the 1960's; that is, I make a simple strongback for building upside down - and for a narrow multihull that can be just one long plank with some crosspieces in the hull's widest mid section areas) then fit the three or four main bulkheads/ringframes, plus the stem and transom to the strongback, then run the keelson, gunwhales and stringers (plantation white cedar in NZ) over and around the heads/frames, these set in and glued into slots cut into the frames. So there is quickly the skeletal shape of your hull. Working on your own makes it difficult to handle the full length, scarfed 3mm klinki hull sides - so I just work a couple of opposing lengths/sheets/sides at a time, that is, glue and staple to the keelson and when it is cured, bend each length round the bulkheads/frames and glue/staple to the gunwhales. Oh, yes, I coat the inside ply with epoxy just before I start bending it, then cove the joints with thickened glue. Working with two or three people you can do the two complete hull length sides at one time ... but you have to work fast and accurately. But on your own, just a couple at a time, works okay. Each ply length is already scarfed both ends of course, so for the next length scarf connection, I do a dry run just stapling, no glue, and pencil mark the correct positions- then glue/staple to keelson etc. coat the interior and move on. After all this is completed and cured, cut the excess ply from the roughly shaped panel sides to the gunwhales. Although this method is not as magical as true tensioned ply building, like the Tornadoes were/still are done, it is sort of halfway between and more suited to one person working on his own. Of course it is a lot easier with two or more people. Hope this clarifies things for you.

 

Thank you Gary.

 

Brorsan, a couple of important points: I start the hull sides attachments to the keelson, frames and gunwhales, in the MIDDLE of the hull, where the double bulkhead/ring frames are, complete that area then work forward and aft from there. You get that mid area completed, coated, glued and coved which stiffens the skeletal structure ... and with this as a sound base, you move forward or aft.
I used a similar method with the Cox's Bay Skimmer, here, although I had false frames to bend the ply around, (removed in photograph);this was 4mm vusa vusa, a quite stiff Fijian "maple."

 

Recent Sid - plus wing rig and main beam drawings.

 

Absolutely beautiful, so much for ply boats looking boxy!

 

I agree, beautiful!

 

Gary, that mast, mainsail combination looks interesting. How are you planning on supporting the leech of the main so that it stands up adequately instead of just twisting off? Is that some kind of camber adjustment shown part way up the mast?