Sunday, October 2, 2011

Replacement of Longitudinal Deck Beams

The below update of October 2nd 2011is also added to the original firts blog to make it a continues story, it can be read under Older Posts, Firts Inspection Storebro 34

                                               Replacement of the Longitudinal Deck Beams
The Deck beams running forward to aft under the deck and against the hull consist of two parts. The aft part till approximately the  forward part of the deck house are made from Pine,  the part of the deck beam running from the forward part of the deck house until the bow were made of laminated mahogany, thin strips, 10 mm, put together in the shape of the hull. The repairs/replacement of these laminated deck beams will be explained in the below text.  As with all till so far found under decks wood these deck beams were rotten away and in some cases repairs was done which have not lasted that long even parts of the beams were missing near the bow.  To make in our opinion a good repair both deck beams, portside and starboard side, were completely replaced. Instead of using mahogany planks it was decided to use marine plywood and of 9 mm thick, and glue these strips with epoxy together, this way creating a strong beams which at the same time , due to the epoxy, should remain water resistant. The choice for 9 mm thickness was made since these strips of wood can easily be bent in the correct shape required to fabricate new deck beams.

The first step was to remove the planks against the deck beam to find out how the original beam was constructed against the deck and against the hull.

The next step was to make a template of thick paper in the form of the too be built beam. This was done by placing the thick paper against the hull and then cut out the form of the too be built beam. After this paper model was finished a template was made of door skin, thin wood which was used as a template to cut the marine plywood which has been used to fabricate the beams. Although on the boat it looks like a straight line there is a curve in this beam as well as that the beam has a torque from aft to the bow.

Beams were made by placing the first strip of plywood against the hull to copy the roundness and bend of the bow. The next step was to glue each layer against each other. Every day one layer was installed to make sure that the epoxy glue had time to cure. Also it was needed to wait a day to remove the screws which were used to press each layer against the other one.

When the beams were finished, they were removed from the ship’s hull and the angle between the deck and the beam was transferred onto the new beam. Beams were temporary shaped with a sander, final shaping was done after the beams were installed and the actual deck beams were fitted between port and starboard, this subject will be explained in a later stage.

Old deck beams were removed from aft to forward and to prevent that the deck would fall down a support was placed on the actual deck beams running from port to starboard under-decks. This support is also needed for the correct position of the new deck beams under- decks.

After the deck beams were placed in the correct position, this is time consuming since a lot of measurements had to be taken to make sure that the deck beams are on the same height, ports side and starboard side above the keel. When we were satisfied with the new position of the longitudinal deck beams they were supported in place with some hull planks.

When they were fixed the rest of the bow planks could be finished, installing these last hull planks is also time consuming since the planks not only run from forward to aft but also from the keel to the deck, so there are two curves in the planks. After a few planks which took a long time to get a correct fit for several planks a paper template was made before the actual plank was cut and fitted in place.

The planks were screwed with brass screws against the new longitudinal deck beams and the frames. It was at the same time found that the most forward frames were rotten so new frames were made in place of the hull; this was done before the old frames were removed and before the old hull was removed.  Since there is quite a bend in these frames they were laminated from oak and glued together with epoxy.

Eventually the new bow is finished, just left were some plugs to be installed when this picture was taken.
The following project is to replace the deck, deck beams between the bow and the deck house.

1 comment:

  1. Hi, following the renovation of the boat. Storö 34 was my dream boat before and I think it has very fine lines. I am very impressed by what you do. Good luck. I follow the developments with excitement ....

    Best regards, Sven-Ake
    svenke.he @