Broken strop on SEAL 28 - 7

More height

Having established that the basic structure shown in figure 12 (previous post) was stable and secure, it seemed appropriate to see how far it could be safely extended vertically, and lift as much as possible of the keel up for cleaning. This could be achieved by placing further blocks under the existing beams. Every operation described so far was relatively straightforward and called for no great strength, with one exception, and that was the lifting up and positioning of the winch assembly on the frame. I have mentioned that it weighed between 12 and 14 kg. Lifting it on to the structure—head height—remembering that the strops were attached, is definitely a two-man job. I managed it on my own by lifting one end, propping it, then lifting the other and so on. The process was not pretty, and not thought-out beforehand; it was the only part of the procedure with which I was not completely satisfied. Going any higher would have been impossible without mechanical assistance. The solution was to use those small lever-arm lifting jacks designed to lift washing machines etc. Figure 13 clarifies the process. Firstly, the keel was lifted until the nylon blocks were well above the keel box. Pieces of timber either side of the keel, long enough to bridge the keel-box slots, were placed appropriately, and the keel lowered on to them. This provided a safe and secure support for the keel and allowed the support structure to be modified. The keel could then be used as a platform—as shown in figure 13—to support the jack. It is important to note that the jack is only lifting the winch and its associated timbers, not the keel…

By slackening the strops, one end of the winch and its bridging timber can be lifted. Blocks are placed underneath, and the jack is then transferred to the other end and the procedure repeated. One note of caution: Slackening the strops can, in extremis, cause the cable end-stops to come out of the end of the slots in the winch nut. In applying subsequent tension, it is possible for the shoulder of the end stop to then catch on the nut causing the strop in question to be shorter than the adjacent one by the length of the stop. Worse case, the winch might need disassembling. The way to avoid this is to keep tension on the strops as much as possible, and only to unwind the winch a few turns at a time.

The ultimate height I was able to achieve in this way is shown in figure 14. With the keel this high, all but 30 cm or so of its vertical length was visible above the keel box and available for cleaning etc. Since at least 60 cm is accessible below with the keel right down, this procedure allows all parts of the keel to be accessed for cleaning, derusting, and antifouling. Some further precautions are, however, appropriate when the keel is lifted this high. It is important to ensure that the blocks used are square and regular in the vertical dimension, and the stacks are vertical and stable. At this height the keel is entirely free and will pendulum in all directions, only loosely constrained by the keel box. For cleaning, and to improve security, the keel can be slightly lowered on to two Stonehenge type supports under the nylon blocks. The verticals can be sized to accommodate different heights. One side can be removed to allow full access for maintenance, with the keel partially lowered on to the support on other side. This stops the keel moving around, while most of the weight is held by the strops for security.​

Cleaning and derusting
 
Analie’s daggerboard keel and its stub companion are made of cast iron. Fifty years of immersion in salt water have taken their toll, and both are badly pitted. Over the years various remedial work has, no doubt, taken place using goodness knows what treatments or fillers. (My dear old granny used to use Polyfiller to repair the rusty bodywork on her old A35 motorcar…) 

Visual inspection was inconclusive, but whatever was on there, apart from rust and antifoul, was quite hard. A stiff rotary wire brush or abrasive pads on my angle-grinder took a long time to do anything and were very hard work. A rock hammer, or an old chisel and hammer likewise had some success but were also very hard work for little progress. Use of the electric chisel was alarming. The chisel was quite blunt, and it was necessary to use it at 90º to get any response, at which point it proceeded to dig a pit… I tried a pneumatic needle gun next. This only seemed to tickle the surface, producing a series of parallel scratches. The method that worked best was a small, sharpened chisel in a Wickes Pneumatic Hammer Drill. The secret was to keep the chisel sharp and present it at an angle to the work to avoid digging in. By weighing the material removed, I’m guessing around two-thirds of a kilo of rust and ‘other material’ came off. 
 
A trial lowering indicated that the keel was free, certainly to the constraints of the cradle. Once I am satisfied that all suspicious extraneous material has been removed, the keel will be coated with Jenolite rust converter, Primocon primer, and antifouled.
 
Peter Maggs, May 2026