Facet Boat

OK. I guess I was a bit too thick headed to catch on. I do think you will need the stiffeners I mentioned, though, to prevent unwanted dips and hollows.

It would be interesting to make a foot long sailing model of this boat.

I intend to make one of at least one of one my growing Facet Boat fleet.

I'm tempted to do one of one of my two 4 Facet designs, just to see how badly it performs. If it performs reasonably well, say a scale 3.0 kts (for 2.4 meter version), I might make a full size boat of this version as a personal sailboat and take it to various wooden boat get togethers and see if I can get people to bet against it being able to sail to windward.

Having absolutely no curves in it, it could probably be made of just about the crappiest exterior grade plywood, or maybe even OSB. Being a very heavy displacement design, it's weight wouldn't be too critical a problem.

 

5 Facet Boats

Onward to the next level of Facet Boats, the 5 Facet ones.

First Off, I added a Facet to Each of the two original four Facet boats, starting off with SEB.

(See first two attachments)

With this boat, I decided to add a Facet on the bottom, to break up that nasty angle. Now there are two somewhat less nasty angles, plus a reduction in Beam and an increase in freeboard. This increases not only the Rocker Height Above the WL (RHAWL) but also significantly increases the Beam/ RHAWL ratio. This is important as this allows the boat to heel further before the lee Bow corner digs in.

With SEB 4, this would happen very quickly as the Beam/Rocker height above the WL was almost 14:1. Poor SEB 4 would probably be sailing with this corner under water much of the time. With SEB 5 this ratio is reduced to a little less than 9:1, which is a huge improvement. Still, there are those nasty angles on the bottom, which, by the way, add up to more than the single angle on SEB 4

Next I moved on to improve SAP 4,

(See second two attachments)

With her draggy raked transom doubling as part of her bottom, her Keel had to be moved well forward to allow her to be able to point up wind.

The solution I chose was to cap it with a real transom. This did Three things:

1.) it allowed a longer WL,
2.) it allowed the deepest part of the hull to be moved forward quite a bit, and
3.) it allowed much higher freeboard at the stern.

All of these improvements probably make for far less drag aft, even thought there is now a nasty stern corner to dig in immediately, as soon as Poor SAP 5 starts to heel.

Even so, with the nastiest bend moved much further forward, I believe it is now safe to move the keel further aft. The still extremely dirty hydrodynamics of this hull might strange canceling out effect. As the lee stern corner digs in, its added buoyancy pushes the bow down, making a bigger bow wave, which will tend to make the boat point up wind. At the same time, this very draggy lee stern corner will be digging in even deeper, tending to point the boat the opposite way. The two effects could end up canceling each other out--with a huge cost in over all drag, of course.

Next up is a newcomer, which I will call DAP.

(See third two attachments)

DAP stands for Double Arrow Point, as she is like two SAP’s joined together, stern to stern, producing two sharply pointed ends. Having five Facets to work with, it is possible to introduce this Hull Plan.

But the four topsides Facets must come together at two rather sharp angles. And the beamier the boat gets, the worse these two angles get. So I limited the Beam to just 10 cm, which is a little less than one third its Length. This caused it to sink quite deep for its Beam. This boat has a very low Meta Center Height, which barely clears the WL. Its buoyancy shift, when heeled, is so slight that it probably has the form stability of a bicycle.

Even so, I drew it with the standard rig, used on the others. Since this boat gets almost all its stability from its ballast keel, not to mention a whole lot of ballast inside the hull, this rig will probably be useful only in very light winds. Still, this boat enjoys a very deep draft, due to her slight Beam and has slightly less whetted area than her two rivals, about 4% less than SAP and about 8% less than SEB. Whether this slight advantage significantly makes up for her very low form stability would be interesting to see.

I drew her with the stern post considerably deeper than her bow post to somewhat make up for the turbulence likely to be caused at where the bow topsides join the bottom. Hopefully, this added hull area aft, while adding very little whetted area, will help her stay on course.