I've been slowly rigging the hull so the roll-over will go as smooth as possible. I've finally scheduled it for Sunday February 16. Come on by if your in the Huntsville Alabama area and help or spectate.
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| You can see the chain hoist attached to the wall in the center far left of the image. This is one of two chain hoists that will slowly roll the boat over. There will be two more on the opposite side preventing uncontrolled roll and two more at the pivot point to prevent the pivot point from moving or scooting along the floor. The two at the pivot point will also be used to slide the entire rig to over mid roll so that we keep the hull to the side of the building. There will be sheet metal skip plates and grease to ease the sliding. |
I've already cranked the chain hoist so that the entire weight of the boat is almost on the pivot point. It took about all that two ton chain hoist and that 6"x6" post could take. Luckily when we actually roll the hull over there will be two rigs rolling the boat. This gives me about a 100% safety margin by my estimation.
BOAT HULL FLIP WAS SUCCESSFUL. Pictures coming soon... actually I did not have time to take a single one myself. Ive got friends though and boy did they turn out for the day.
Here is a taste:
I learned a lot during this maneuver. It took a minimum of 6 chain hoists with a minimum capacity of 2200 pounds (1000 Kilograms). We also had three more come-alongs that proved convenient. Sheet metal was laid down as tracks for the wooden rollers and the wooden rollers were liberally greased to allow easy sliding. This turned out to be critical. We always had control using chain hoists on one side to pull while using chain hoists on the other side to release. We also always had chain hoists controlling the pivot point on the ground.
After the half way point, the pivot point control had to be switched to the other side while we used the come-alongs to slide the hull over opposite the pivot control. I used 1/2 inch (12.7mm) eye bolts for all attachment points and most importantly, I welded the eyebolts closed so they would not open under stress. This is critical. Either use eye bolts that are factory welded or weld them yourself. If not they will pull open. We always had two chains for redundancy and to make things easier. You will need a spare come-along or chain hoist to relieve tension on the chain when re-rigging. At no point did we have a single chain taking weight. Although it was not the chain that concerned me but the point of attachment. There is a lot of stress on those points especially when the chains are at steep angles to the eye bolt.
It is also a good idea to have spare 5/16" quick links for adjusting the rigging. Make sure all your chain and hardware exceeds your chain hoist capacity by a good margin. There were times where we were actually pulling against each other putting huge stress on the hardware (and hull). We learned quickly to recognize these situations and avoid them. Avoid shock loading. I used rubber bungees on the chains as a snuffer for the side that was releasing so that when they took the load, the bungees would absorb the shock. I discarded them on the re-rig (when switching sides) after I determined that going slow was good enough and the bungees caused some difficulty when trying to re-rig. This maneuver took 4 hours and required 6 people to complete.
Feb 26.
I've started marking lines on the bulkheads. Lines to cut (actually cut one) and lines where attachments will be made for the interior. Mostly, I'm looking forward to having a passageway along the interior so I don't have to climb over the bulkheads to get from one end of the boat to the other. I've also cleaned up the shear but have not removed the temporary shear clamp yet.
