Wednesday, October 22, 2014

Keel repairs III

                                                             Keel repairs III

This will be the last update on the keel repairs since some items were not covered in the earlier blogs with regards to the same subject.
When the stainless strips are removed, most of them fell off by themselves, one can see that when they were mounted the last time that there has been not a full surface contact between the stainless steel strip, sikaflex and the ships keel.


This could also be the reason that the wood started to deteriorate at the point where the sikaflex touched the wood, open voids between the two.
Other reason could be that bronze or brass screws which have been used to fix the Stainless steel strips against the keel failed. In my opinion this created a “Battery” with the result that the screws fall apart over time and therefore lost their strength to fix the stainless steel strip against the keel.

With the removed strips wood was repaired where necessary as explained in earlier blogs.
We are now at the point that new wood has been inserted painted several times with primer for the underwater paint, 6 coats, and we could start with installing the stainless strips again.
 The strips had a lot of old paint and this was removed as well as sanded to make sure that a good contact would be created between the stainless strip and sikaflex. The sides were thoroughly cleaned as well.

During the cleaning of the strips it was noticed that there was some wasting of the stainless steel at the points where the keel bolts are positioned in the keel, which gives me the indication that the stainless steel is not 316 but 304.

When all was cleaned to my satisfaction the stainless strips were cleaned with acetone for degreasing them, same was done with the keel.
The stainless strip was 100 percent covered with sikaflex Seal and Glue and screwed with stainless steel screws against the wooden keel.
A large amount of sikaflex was pushed out between the two and this was removed.
Last step after removing the excess of sikaflex was to turn all screws a quarter of a turn, could not turn them anymore, to get a little more sikaflex out and create a small roll of sikaflex on the side of the stainless strip.
At this moment it could also be checked if there was 100 percent surface contact between the strip, sikaflex and keel.

 Last repair item on the keel was a small damage on the starboard aft bottom side of the keel.

 I could have filled it with wood filler but since I would like to make permanent
repairs and did not know how much wood was rotten and the wood of the  affected area was removed.

New wood was glued in and fixed with stainless steel screws, bearing in mind the grain of the insert.

At the same time some holes above the removed wood were drilled out and filled with plugs.

All was sanded smooth and painted with several coats of underwater paint.

No comments:

Post a Comment