Sunday, August 17, 2014

Ooops! Iroquois, we have a problem!

I don't live anywhere near Houston so I thought I'd substitute Iroquois and you'd still get the reference to the Apollo 13 incident. Flipping this hull over has got to be one of the most challenging parts of the whole project. At least the most worrisome. I've seen it done on the Internet, read about it in a few blogs and viewed every available video on Youtube. I know it can be done and I've never attempted anything like this before so I think I'm being over anxious. If we screw this up and wreck the hull it's game over. I'll be lucky to liquidate everything I've bought for the boat for pennies on what we paid for it so the risk is not trivial.

Anywho, last night I was going over the plan to flip this thing over. I even watched my own animation a half dozen times. This one, you might remember it from a previous posting.
Making it happen safely relies on a bit of eyeball engineering, overbuilt lifting gear and carefully coordinated pulling & feeding out of the cables attached to the turning rig. Getting it flipped onto its side is pretty straight forward. The main electric winch lifts up on the frame as the hand winch pulls the bottom of the frame sideways.
Once the hull is on its side all is well. The pulling stops. This is where it gets a bit tricky and the part I totally missed in understanding how this will all actually work.
In order to get the hull to continue to roll I have to feed out line from the electric winch while the hand winch continues to pull the hull sideways. That's fine but there's nothing there to lift the side starting the second half of the flip. That's what I missed. A second pull to lift the hull again. I can't use the main electric winch as it's being used to control the roll and prevent the hull from falling to the ground.
So I've had to add another hoist of some sort to lift the hull on the second part of the flip. I don't have another electric winch so had to rig up something else. I have a puller type of thing that I bought years ago probably with this exact purpose in mind. It doesn't have a long pull, about 6' but is capable of pulling 6000 lbs.
This should be enough pull to get the hull past the tipping point where gravity will do the rest and the electric winch will control the lowering of the hull to the ground. It's not an eloquent solution but I believe it will work.

Bracing straps have been rigged to the top of the Gin Pole. You can see them clearly in this pic. The large one in the middle will exit the side of the shed and be attached to a ground anchor in my neighbors back yard. This is the one that will take most of the strain from the flip.
I hope that's the end of rigging on the Gin Pole. Back to cleanup under the boat.