Re: Double-loop hull flipping method
Thanks Tom. I'll give it a try.
Reed
Reed
Reed,
Right. Before the lift, I make the double loop all tight against the hull. During the life, one loop is still tighter, while the lifting-block loop pulls away with slack and stretch. I didn't try a single loop; so, I can't compare.
The rafter block has to be high enough to account for the widest hull dimension (maybe a diagonal), distance from lifting to rafter blocks, plus slack/stretch. I have ten feet. I've had my hull hanging free, pretty much on beam end, clear of the strongback. I've then pulled the lower side toward me as the hull lowered.
I would find it hard to get boat-flipping parties together at just the right times. So, this method worked well for me. I did it alone once, scurrying back and forth between boat and car. The other times, my son drove. Without him, in the lowering phase, I pulled the side over with a tied-off line.
The flip goes smoothly, but it does pick up speed at one point, especially, as I remember, when starting bottom up--having to do with the CG being low in the hul, or so it seemed. This is another reason to be conservative and be with the boat as it goes over, while someone else slowly, slowly drives the lifting vehicle with pre-arranged stop and go signals.
I found the idea on the web somewhere, don't know where. There might be more explanation there. The motion reminds me of the child's toy that has wooden rectangles strapped together such that, when you hold the whole thing by end, a block appears to tumble all the way down.
Tom Andrews
Right. Before the lift, I make the double loop all tight against the hull. During the life, one loop is still tighter, while the lifting-block loop pulls away with slack and stretch. I didn't try a single loop; so, I can't compare.
The rafter block has to be high enough to account for the widest hull dimension (maybe a diagonal), distance from lifting to rafter blocks, plus slack/stretch. I have ten feet. I've had my hull hanging free, pretty much on beam end, clear of the strongback. I've then pulled the lower side toward me as the hull lowered.
I would find it hard to get boat-flipping parties together at just the right times. So, this method worked well for me. I did it alone once, scurrying back and forth between boat and car. The other times, my son drove. Without him, in the lowering phase, I pulled the side over with a tied-off line.
The flip goes smoothly, but it does pick up speed at one point, especially, as I remember, when starting bottom up--having to do with the CG being low in the hul, or so it seemed. This is another reason to be conservative and be with the boat as it goes over, while someone else slowly, slowly drives the lifting vehicle with pre-arranged stop and go signals.
I found the idea on the web somewhere, don't know where. There might be more explanation there. The motion reminds me of the child's toy that has wooden rectangles strapped together such that, when you hold the whole thing by end, a block appears to tumble all the way down.
Tom Andrews