Grob

Wouter just answered that up a couple of posts....

"If a F11 platform still needs 5 sheets of ply, same as the F12'10". The only difference is that at after the building is done you are left with more waste."

Please show me your math grob...
Based on Johns cad drawing posted on the other thread, which everyone seem to like for the most part… the 12'-0" F12 you would need
4 Pieces 12-1/2"X 8'-0" for the decks
8 Pieces 14” X 8’-0” for the hull sides
8 Pieces 7-1/2” X 8’-0” for the bottom panels.
2 Pieces 12-1/2” X 8’-0” for two bulkheads per hull and the transoms.

Now lets just forget about the fact that all these pieces have to be cut in one piece from a 4’ wide piece of plywood for now…which is a huge issue…lets just add all the pieces together
4 X 12-1/2” =50 inches
8 X 14” =112 inches
8 X 7-1/2” =60 inches
2 X 12-1/2” = 25 inches
247 inches Divided by 48” = 5.14sheets
49-7/32” =5.02 sheets
Even giving you the fact that you will save material by nesting the parts, you will need most of that just to get the boat cut out of five sheets.

Some are saying we will keep it 12’ so there is only one joint between the 8’ panel and the four foot panel…did you forget about the 7X the thickness for the scarf joint? Lost another 13/16, and another 1/8” for the saw cut when you cut the panel in half to get the 4’ long pieces…and then there is the curve in the bottom and the sides, both of which will shorten the overall length, the most drastic curve will dictate the length of the boat…so now we are a couple of inches shy of 12’…oh but we can go thru the trouble to scarf the plywood again to add that couple of inches back on, but it was too much trouble to scarf 10” ….

I will say if you are using metric plywood the length will not be an issue, since it is slightly longer at 49-7/32” X 8’-2”. For those of us in the US, going to Home Depot for common exterior plywood (not recomended), you will definitely run into this problem.

If one would step back and look at the benefits objectively, they would be hard pressed to come to any conclusion other than to go for the increased length.

Regards,
Bob

To a 7- or 8-year-old child do you know how BIG a 13-foot cat looks compared to an 8-foot, pram-nosed dinghy? Even a 12-foot cat is kind of pushing it for the little kids. I'm trying to keep an open mind about it and am willing to experiment on my grandkids to find out whether a 12-footer is too big.

Maybe children are bigger in the Netherlands. My two oldest grandchildren only weigh about 60 pounds each, and the oldest one just turned 11. Most of the kids we know are pretty skinny.

My step-grandchildren include a 17-year-old boy who weighs 135 lbs and a 15-year-old girl who weighs 110 lbs. They both know how to sail but are too involved now in all their other sports activities.

Maybe I am just not thinking "heavy" enough.

"My step-grandchildren include a 17-year-old boy who weighs 135 lbs and a 15-year-old girl who weighs 110 lbs. They both know how to sail but are too involved now in all their other sports activities."

When my son was in high school one of the kids on the sailing team (420s) was 14 or 15 years old 6' tall and about 205lbs...He was the youngest guy on the team, and one of the best sailors on the team. Kids come in all sizes...a slightly bigger platform would help keep the bigger kids in the mix.

Remember if it’s a formula class you can build a boat tailored to your Childs physical characteristics. If 12'-10" seems too intimidating you can always built one 12'-0" or even smaller... But if the platform limits are set too small some of the bigger and/or older kids might not get a chance to participate.

Regards,
Bob

Going back to the US weight and stature for age charts.

Mary,
The 17 y.o. boy and 15 y.o. girl are both at 37 and 40 percentile (compared to average)

Bob,
WHAT THE HELL WERE THEY FEEDING HIM? At age 15 (high side) he was well off the chart for weight and at 96 percentile for height!

The 11 y.o. young lady I'd like to have sail this boat is at the 80 percentile for weight (100 pounds)

"WHAT THE HELL WERE THEY FEEDING HIM? At age 15 (high side) he was well off the chart for weight and at 96 percentile for height!"

He was a big kid...not a fat kid...his dad is 6'-6"

As far as those weight charts...I think some of those lower weights in the "normal" range look more like heroine sheik...

Regards,
Bob