By David Nichols - Austin, Texas - USA


Turning Over a Hull

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Every one who builds a boat upside down is faced with the task of turning it over at some point. Small, relatively lightweight boats present no real problems. You can just grab a friend and with about a minute’s worth of planning turn it over. But what if the boat isn’t so light weight?

The first boat I ever turned over was a 16 foot Swampscott Dory. It wasn’t very heavy really, about 70 or 80 pounds, but the weight was concentrated in the bottom. The friend I had asked to help and I both got a surprise when we started to rotate the boat. When it reached a certain point the heavy bottom that was on top suddenly flipped down. It was almost instantaneous. We managed to not drop the hull but we both hurt arms and shoulders.

The next boat I turned over I planned better and remembered that gravity is always at work. As a result the boat was turned over without incident but what if the hull weighted 700 or 800 pounds instead of 70 or 80 pounds?

Boat yards have gantries or other clever devices to rotate large hulls. Cris Craft used a system that worked kind of like a spit. The boat was rotated like a large turkey or roast. I turned over a 28 foot hull using a large gantry, hoists and two other men. Each yard seems to have its own system they use to rotate hull after hull.

The builder working in his or her garage doesn’t have the money or inclination to build a system for turning hulls so what are the alternatives? I know of one hull, a 17 foot cat boat, that was easily turned by fifteen or sixteen guys invited over for beer and bar-b-que. With about 8 guys per side the boat was picked up and carried out of the garage and turned over. The builder had used a large number of 2X4’s set athwart ship to support the sheer so the boat was set on edge and then rotated over. Then it was picked up, set in a cradle and moved back in the garage to finish out. The boat was turned over first and then the keg was tapped. It’s important to do things in that order.

I was able to only entice 5 friends with beer and bar-b-que to help turn a 700 to 800 pound sail boat hull so I had  a great deal to do ahead of time.

The cradle I planned to build was square and captured the boat at stations 3, 4, and 5. This was the mid-section of the hull and would hold it securely during roll over. I’ve learned over time to plan ahead so I drew the cradle to scale and rotated the square to see how much clearance and space was required. That information told me where I needed to move the hull in order to safely rotate it.


Photo 1

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The first job was to drag the hull and strongback out of the shop. I had built the small strongback with that in mind. There were supports to allow me to attach a chain bridle to the strongback (photo 1).

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At first my son and I were able to move the whole unit by putting 3 steel pipes under the unit and rolling it on the pipes (photos 2 and 3). It was necessary to make a turn as we came out of the shop so a ply bar was used to shift the aft of the strongback over (Photos 4 and 5).

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After we made the turn and the whole unit was outside the shop we had to hook it up to a truck to drag it the rest of the way (photos 6 and 7). During the move a crack developed in the strongback causing it to drag and created too much resistance for the two of us to roll it. With the truck it was a simple matter to drag the whole unit under the canopy outside my shop.

Once under the canopy I had time to consider how things could have been done to make the job easier and accomplished by one person if necessary. The next strongback will have the sides beefed up. I’ll use plywood backed by 2X4’s or several layers instead of just a single layer of plywood. I was lucky that everything held together through the whole move. Had the strongback separated it would have created some major problems that would have delayed the roll over.

Another change I’ll make is putting the strongback on small blocks that will give enough clearance to place the steel pipes underneath it. Once the pipe is in place and the unit is ready to move the blocks can be knocked out. With those two changes the boat could have been moved by one person. I hesitate to say easily moved by one person because it is a big hull but the move out of the garage could have been done solo.

Photo 8

Building the cradle could have been done solo as well but an extra pair of hands made the job go much faster. We started at station 4 (photo 8), the mid-section of the boat, then moved to 5 and then 3. The cradle was built with 2X6’s which may have been overkill.  It was the thought of the cradle breaking during the roll over that convinced me that the cost of the 2X6’s was justified.

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Photo 9 shows how we captured the hull with the 2X6’s and 2X4’s and Photo 10 shows how the cradle was attached to the bulkhead. There are other ways to capture the hull I’m sure and any method that keeps it from shifting, even a small amount, will work. Station 5 was framed in the same way as 4 but station 3 was slightly different.

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For station 3 we screwed 2X4’s to 4 and 5 to create supports that put 3’s 2X6’s on the same level as 4 and 5 (photo 11 and 12). Note the spacer resting between 3’s 2X6’s and the keel. The vertical legs on 3 had to be in line with the verticals on 4 and 5 as well and this put it slightly out from the hull (photo 13). When the 2X6’s formed a cube we finished framing in and capturing the hull (photo 14).

After the hull was completely framed in it was ready to drag in place and roll over. All of the above work was done a day before everyone was scheduled to arrive. I was very glad I started early because even with my son helping and doing a great deal of the work under the boat it took longer than I estimated. I think it is a fairly safe bet that building the cradle will take longer than you think.

Actually, the roll over will probably take longer than you think, as well. We started on a late Saturday afternoon and almost ran out of light so on the next roll over I will start in the late morning.

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When everyone started to arrive we used the truck to drag the hull into position (photo 15). I attached a belay point to the truck, a nearby tree, and the cradle (photo 16). I felt this was very important and was  needed to control the cradle. Even with more helpers I would have still used the belay point or dead man. There is no question that with jacks and the belay point the hull could have been rolled over by one person. It would be a very slow and a some what risky process but it could definitely be done. I had considered the possibility that I would have to roll the hull with just the help of my son and we could have done it but I’m very glad I had as much help as I had.

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Once we started the roll over process it went very quickly. With the hull and the cradle on its side (photos 17 and 18) the strongback was cut away and set out of the way. Then we dragged the cradle back to the starting point for the next stage of the roll over and repeated the process (photos 19, 20, 21, 22, and 23).

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Actually getting the hull out of the cradle proved to be the most difficult part of the process but even that was fairly simple. The hull was just rocked back on its stern and several people slid the cradle out from under the hull (photo 24). The difficult part, for those holding up the hull, was having to step over the cradle as it was drug out from under the boat. If it had just been my son and I we would have blocked up the hull and cut the cradle out from under the hull with a Sawzall.

Photo 25

When we had the hull on the ground we used the pipes again to move it back into the shop (photos 25). I was surprised how easily the hull rolled on the pipes. In fact the helpers in charge of keeping the pipes under the bottom kept telling those pushing to slow down. My son and I certainly could have pushed the hull back into the shop and I believe one person could have done it as well.

Photo 26

With the hull right side up and back in shop there was nothing left to do but clean up a bit and open a cold drink or two (photo 26). I fed everybody bar-b-que and the post roll over party was a good time. It’s only fair if you ask friends and family to help with the roll over that you feed them well. To do otherwise is to assure that you’ll roll over the next hull solo.

For those who might be tempted to skimp and save a few dollars on the cradle and refreshments for the roll over crew let me offer this caveat: during the life of your boat it is probably at the most risk during roll over. So plan well, build a very strong cradle and feed the roll over crew well….after the boat’s turned over

More columns by David Nichols

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