Deep water entry test
7 Comments Published by Adventures of Greg on Tuesday, June 12, 2007 at 6:05 PM.
This sequence shows how I will get into WiTHiN from deep water. I build a wood frame that simulates the size and general shape of a door that I will cut in the side of the top deck. This door will swing open like a gull wing door. The bottom of the opening is a few inches above the water line. I can kick myself in through the door head first, put my hand down on the flat seat (the seat has to be fully reclined first), push my head and upper body up with my arm, sit on the seat and then finally pull my knees through, then feet. It's actually fairly easy. I reverse the procedure for exiting.
The other part of that strange looking wooden contraption is holding 60 pounds of weight at the exact location of the center of mass of the top deck. The top deck weighs 60 pounds, so this simulates exactly what effect the full top deck will have on the stability of WiTHiN.
My first test ride included only 25 pounds on the floor as ballast to offset some of that 60 pound weight up high. She definitely rocked much slower than before due to the center of mass now being further away from the center of roll. She also sat lower in the water due to the extra 75 pounds and sharp turns came very close to flooding the cockpit. Flooding during a turn or from waves will not be an issue with the top deck on unless the hatch is open. On the ocean, I will need to think about a bailing system for when that hatch is open and waves splash in, or I am getting in or out.
When I go into a turn, WiTHiN leans into the turn for a second or two, then she leans the opposite way. When I re-center the rudder, the opposite lean continues for a second or two, then she levels out. I call this 'recoil steer'. It is caused by the position that the rudder and drive leg take during a lean into a turn. I'm not sure I completely understand what is happening under the water, but this is normal. With the 60 pounds on top, the recoil steer seemed exaggerated, but again, this could be due to the increased displacement from the extra weight.
Next on the agenda is rigging up some lines for the rudder instead of my push/pull rod. Then I can prepare the top deck (insert the 2nd half of the bulkheads), and glass the top deck right onto the kayak hull. Then, I can cut out the door, and cut out the window. Then I crawl in and finish off glassing the bulkhead seams, and inside perimeter of the top deck. Then the window and then small hatches for the rear and front compartments. Finally, I need to add vents and a couple of windows - small hatches that open for fresh air - one on the ceiling and two for each side (left hand side window will be on the door).
Labels: boatbuilding
