... that a high roll moment of inertia was beneficial in the single 'rogue wave' circumstance. Yes, they were talking about a single wave. I think that...
165
Alex & Kim Christie
ravencoast@...
Jun 1, 2001 4:27 pm
... On Brent's boats, I think the high deadrise of the hull bottom midships would adequately handle the load imparted form an impact on the bottom of the fin...
166
brentswain38@...
Jun 2, 2001 8:27 pm
One of my boats spent 16 days punding on a lee shore in 12 foot surf before being dragged through the surf, being picked up and dropped 12 feet every wave for...
167
Gary H. Lucas
garyhl@...
Jun 2, 2001 9:46 pm
I took a look at the pictures of the guy building the 36' boat, and the site where they are building in aluminum using the origami method. The pictures of the...
168
Alex & Kim Christie
ravencoast@...
Jun 3, 2001 4:07 am
A folder of Winston Bushnell's Dove III has been uploaded to the files section for your interest. This is the Swain 26 (Centreboard and stub keel) boat which...
169
Gary H. Lucas
garyhl@...
Jun 3, 2001 1:40 pm
Brent, I am trying to understand how the metal deforms when bending up a hull. It seems to me that the steel remains as a developable shape as it is bent. ...
170
turpin@...
Jun 3, 2001 2:08 pm
... A topologically flat surface stays topologically flat (no compound curves), unless you somehow stretch the material. That's mathematics. As to the...
171
Alex & Kim Christie
ravencoast@...
Jun 3, 2001 3:39 pm
Hi Gary, and welcome to the group. There may be a delay in Brent answering your question, as he has to get to a public terminal, so hang in there for a day,...
172
burr.halpern@...
Jun 3, 2001 6:15 pm
This is begining to make a lot more sense. Originally, these boats were described as "frameless" and I reacted rather negatively since from an engineering...
173
pvanderw@...
Jun 3, 2001 7:49 pm
... Because steel, like most materials, is stronger in compression than in tension, a sheet of steel will not always bend into the theoretical ruled surface....
174
burr.halpern@...
Jun 3, 2001 8:05 pm
While it is posible to form steel into compound curves (look at most any automobile) the tools required are beyond those available to most amatuer boat...
175
turpin@...
Jun 3, 2001 9:01 pm
... Thinking about this, a few minutes after I posted, I realized that the topologically flat sweep between two curves is not unique. In most cases, there is...
176
Alex & Kim Christie
ravencoast@...
Jun 4, 2001 5:33 am
Just found this site from Duckworks magazine, which has a link for a tortured plywood solo canoe. The patterning is sort of similar to the Brent Swain style...
177
Alex & Kim Christie
ravencoast@...
Jun 4, 2001 5:37 am
to err is human... Here is, at last, the URL for the folded ply solo canoe: http://www.duckworksmagazine.com/articles/swampyankee/index.htm Alex Christie ...
178
pvanderw@...
Jun 4, 2001 3:01 pm
... More thought may be required, because Mother Nature is imposing more restrictions than you are considering. It is not enough that the surface of the sheet...
179
turpin@...
Jun 4, 2001 5:54 pm
... IF the modeled surface has no compound curves THEN it can be unfolded (unrolled) onto a flat sheet isometrically, i.e., in a fashion that preserves...
180
pvanderw@...
Jun 4, 2001 6:47 pm
... It is possible to create a compound curve by sweeping with a line. In fact, it is possible to create a saddle point surface (concave down on the x-axis,...
181
turpin@...
Jun 4, 2001 7:28 pm
... This raises the question: What do you mean by "sweep"? Take any smooth 2d surface. If there is a part of the surface where you can lay a straight edge so...
182
pvanderw@...
Jun 4, 2001 8:49 pm
... Here is a web page with drawings of a number of "ruled surfaces," including a saddle point (Example 1) ...
183
turpin@...
Jun 4, 2001 9:31 pm
You're right. I need to rethink my reasoning. Russell...
184
burr.halpern@...
Jun 4, 2001 10:38 pm
Actually, I think that you are discribing what in math terms is called a 'hyperbolic paraboloid'. A hyperbolic paraboloid does not produce a compound curved...
185
Gary H. Lucas
garyhl@...
Jun 5, 2001 12:36 am
I tried several 3d programs a few years ago to see if they would be useful to me. I spent a few days with several different packages and found that after a...
186
cdbarry@...
Jun 5, 2001 2:05 am
A developable has to have zero Guassian curvature. This means that two adjacent rulings have to be co-planar, or that the cross product of the cross product...
187
pvanderw@...
Jun 5, 2001 12:49 pm
... called a 'hyperbolic paraboloid'. A hyperbolic paraboloid does not produce a compound curved surface but is a developable surface, again made up of conic...
188
halgordon@...
Jun 5, 2001 7:57 pm
Has anyone built The Cutter, Bedouin? Or the Mini Kat?...
189
Alex & Kim Christie
ravencoast@...
Jun 5, 2001 9:36 pm
I have been waiting for a week for a reply from Kasten as to which of his designs have been built, but have so far not heard back. His last e-mail suggested I...
190
brentswain38@...
Jun 5, 2001 11:13 pm
In theory the hull bends in one direction only, but in practise the shrinkage from the cutting torch and welding shrinks the edges of the plate, leaving about...
191
brentswain38@...
Jun 5, 2001 11:19 pm
Alex is scanning the plate shape which should answer a lot of these questions. You can build a rugged model by cutting the pattern out of a flat sheet of...
192
cdbarry@...
Jun 6, 2001 1:06 pm
... pictured ... A hyberbolic paraboloid is a ruled surface, but is not developable. Developable surfaces must be ruled, but not all ruled surfaces are ...
193
pvanderw@...
Jun 6, 2001 2:14 pm
... Yes. When I said otherwise in post 187, I was reacting off the cuff to post 184, and I realized that I had made a mistake just about as soon as I hit the...
