DaveH6
Big nuisance.
This area is about 7' aft of the stem and was a dished out area in the plywood bottom when viewing the overtuned boat. Although this occured near a scarf joint, my panels were glued together on a flat concrete floor thus flat in shape.
One guess is that when the bow area was being unfolded and tortured into shape the scarf caused the plywood to misbehave. But I can't explain why the starboard panel didn't do the same.
View my picture titled "without rocks its a Venus fly trap" found in the Creating a Hull picture set. On the port panel look at the first scarf from the bow. I now can convince myself that I can see the convex area. I thought that the problem was an act of God but not so as I should have seen an inverted V shape on this bottom panel's edge and weighed it down before wiring the bottom to the topside panel. Once the misaligned panels were taped, my goose was cooked.
When wiring the panels together I suggest not getting too excited over the immense fun at hand of creating an instant hull. Slow down and take the time to take a careful look at the alignment. I spent 4 hours correcting the problem.
The prescribed pencil reference line (shows were the bottom and topsides will join) on the aft portions of the topside panels made that part of the alignment and subsequent wiring a breeze. Lacking a penciled alignment line in bow area, take your time when wiring the panels in thls area.
The fix. I used temporary drywall screws to hold down a piece of Joubert plywood epoxied into place. Then I used a belt sander to get the wood to a rough dimension. This stage is depicted in the picture.
Next I used a 4' long by 2 3/4 wide 40 grit sanding board and thin layer of microballoons to blend in the patch with the rest of the hull. Some would say use fairing compound only to fill in the dished out area but I say this stuff is brittle and can crack if applied too thick. Both sides of the hull are now symmetrical thus the problem has no consequence in regards to performance.
But, I have convinced myself that one day I will impact a rock on Lake Travis and the impact will be in this thickened area thus saving the boat. Is this a case of "everything happens for a reason"?
* Edit: 12/29/2011. I enjoyed a recent visit from a fellow Bluejacket builder who was in the process of stitching his hull together. He told me of the effect on hull fairness as he repositioned the temporary hull support under the v berth area. The designer believes that a temporary hull support under the v-berth area is a possible cause of my problem. Beware of bottom panel fairness issues especially with the weight of a person inside the hull working on the v berth framing and perhaps forcing a hull support into a bottom panel. However, there remains the possibility that when torturing plywood into a compound bend, stuff happens thus hull supports may not be the culprit.
Big nuisance.
This area is about 7' aft of the stem and was a dished out area in the plywood bottom when viewing the overtuned boat. Although this occured near a scarf joint, my panels were glued together on a flat concrete floor thus flat in shape.
One guess is that when the bow area was being unfolded and tortured into shape the scarf caused the plywood to misbehave. But I can't explain why the starboard panel didn't do the same.
View my picture titled "without rocks its a Venus fly trap" found in the Creating a Hull picture set. On the port panel look at the first scarf from the bow. I now can convince myself that I can see the convex area. I thought that the problem was an act of God but not so as I should have seen an inverted V shape on this bottom panel's edge and weighed it down before wiring the bottom to the topside panel. Once the misaligned panels were taped, my goose was cooked.
When wiring the panels together I suggest not getting too excited over the immense fun at hand of creating an instant hull. Slow down and take the time to take a careful look at the alignment. I spent 4 hours correcting the problem.
The prescribed pencil reference line (shows were the bottom and topsides will join) on the aft portions of the topside panels made that part of the alignment and subsequent wiring a breeze. Lacking a penciled alignment line in bow area, take your time when wiring the panels in thls area.
The fix. I used temporary drywall screws to hold down a piece of Joubert plywood epoxied into place. Then I used a belt sander to get the wood to a rough dimension. This stage is depicted in the picture.
Next I used a 4' long by 2 3/4 wide 40 grit sanding board and thin layer of microballoons to blend in the patch with the rest of the hull. Some would say use fairing compound only to fill in the dished out area but I say this stuff is brittle and can crack if applied too thick. Both sides of the hull are now symmetrical thus the problem has no consequence in regards to performance.
But, I have convinced myself that one day I will impact a rock on Lake Travis and the impact will be in this thickened area thus saving the boat. Is this a case of "everything happens for a reason"?
* Edit: 12/29/2011. I enjoyed a recent visit from a fellow Bluejacket builder who was in the process of stitching his hull together. He told me of the effect on hull fairness as he repositioned the temporary hull support under the v berth area. The designer believes that a temporary hull support under the v-berth area is a possible cause of my problem. Beware of bottom panel fairness issues especially with the weight of a person inside the hull working on the v berth framing and perhaps forcing a hull support into a bottom panel. However, there remains the possibility that when torturing plywood into a compound bend, stuff happens thus hull supports may not be the culprit.