Tuesday, September 9, 2014

Journal of the Molly B

While researching option on how to flip my boat hull I stumbled across the Journal of the Molly B. The Molly B is a modified Glen-L Argosy which the builder, Tom Schmidt, built starting way back in 2002. I immediately purchased and downloaded the first three of his journals to see what info I could glean from it's pages. With Tom's permission here are some of the photos and details of how he flipped his 40' hull.

First thing you'll likely notice are the rolling frames and Gin Pole. These allow the hull to be flipped basically within it's own shadow. The hull Tom built has much of it's framing already installed so there's no need to overdo the rolling frames. He's pulling from a single point with a chain hoist in much the same manner I'll lift my hull.

Up she goes. As the main hoist lifts the hull the bottom rolling frames will want to move towards the gin pole. In my instance where I don't have a whole lot of extra room we'll pull the bottom as we lift.

In the above pic you can see the internal structure in the hull. The rolling frames and lifting points are tied to these (temporarily). They provide the structural integrity to the hull as it's lifted. At the point the hull is in that pic there's the greatest force being applied to the hull trying to collapse it.

This is the point of no return. The boat will go to the floor. The maximum stress on the gin pole is also at this point when the hoist is at max extension. The tendency will be for the rolling frames to want to scoot out from underneath the boat towards the gin pole dropping the hull to the ground. I've planned for this and will have a couple of bodies with tag lines standing by to arrest the slide if it happens.

So in a nutshell that's how it works. Looks easy. In theory it is. In practice, well we'll see how it goes.