Work continues at GRP Marine: with the damaged panel now cut out of the boat, we could start rebuilding the hull using the new panel which IDBMarine had moulded and sent to Jersey. The first step was dry fitting to make sure that the new panel fitted in the hole we had cut out without stressing or bending and that as far as possible, it would lie flush with the rest of the hull to avoid fairing problems later down the line.
For this we screwed wooden "tags" around the outside of the hole and offered up the new panel a number of times. With some judicious grinding, we achieved a good fit and were keen to get on with bonding the new panel in place. Once the panel was bonded to the skeletal ribs and stringers, we would be able to glass the new panel to the ribs and stringers which would then allow us to remove the wooden tags and glass around the outside of the new panel.
A quick note on terminology - "glass" as a verb is used interchangeably with "laminating" and means laying down layers of cloth (made of you guessed it, glass fibres hence "fibreglass") saturated with a 2-component resin which cures chemically to produce a laminate whose strength depends on the type of resin and the type, number of layers and orientation of the glass cloth. An important step in "glassing" is to prepare the surface which the "glass" will bond to through abrasion to ensure a good mechanical bond. Without this step, the "glass" will simply peel off the existing structure.
"Bonding paste" is essentially glue which is made up of the same 2-component resin used for laminating but this time thickened to form a paste of the desired consistency with an additive, in our case "colloidal silica" which is a white powder.
Alongside the replacement of the damaged panel, we were also working on the required modifications to the boat. We had received a kit from IDBMarine for these modifications divided between the structural reinforcements inside the boat and the improvement to the keel. The materials for each modification were specified as were the quantities of resin and bonding paste required. We were also provided with schematics from David Raison which helped us to understand exactly what was required for each modification.
The first step we had taken back in April was to cut out the elliptical inspection hatch in the forward buoyancy compartment and now we were glassing, it was time to create the lid for this hatch out of the panel we had cut out. This involved glassing a lip around the panel which we would trim to size once we had prepared the edges of the hole inside the boat.
The eagle-eyed among you will note the fabric with the red and blue stripes laying over the area we glassed. This fabric is aptly called "peel-ply". It is impervious to the resin and is peeled off after the resin has cured which leaves behind a lightly textured but even surface which can be glassed over or painted without further preparation.
Next on the modifications list was the addition of a 50mm band to the trailing edge of the keel. Since I would be applying a new antifoul to the keel, I sanded the whole keel including the bulb. We then had to line up the new additional strip with the keel blade which we did with battens and then by tacking it in place with fast-curing body filler which then allowed us to complete the bonding with stronger but much slower curing bonding paste. Each side of the keel was then covered in a layer of glass before the fairing process started with the application of successive layers of watertight epoxy filler.
The pace in the shed was frenetic at times as we cut cloth, mixed resin and bonding paste and applied it all in the right places before it went off. However there were also periods of down time as we waited for the resin or bonding paste we had applied to cure. These times were perfect to sort out some of the smaller side projects that Mini Skippy also needed doing.
The days were long in the shed and progress was fickle - it wasn't always easy to see the amount of time spent sanding and preparing as progress, let alone thinking of all the sanding, preparing and cleaning up still to come!! However, the days flew past and we reached a huge milestone - we finished bonding and glassing the new panel in place. We were going to be able to start work finally on the internal structural modifications!
At first look, some of the modifications seemed very simple but after a little reflection, they still had their intricacies. The first modification we could tackle inside was the additional rib underneath the cockpit. Using the plans, we determined where we needed to position the plywood rib and with some final shaping, we made sure it fit before sanding and bonding in place. Then to reinforce the join, we had to glass as well and this required some fiddly cutting, particularly around the central stringer which has an L-shaped profile.
The next modification on the list was the additional reinforcing skin of cloth on the inside of the hull. This additional layer of cloth inside the hull was designed to limit the propagation of any cracks should damage occur to the structure. However it also required sanding almost the whole inside of the bow to remove the layer of G4 sealant which is applied to the inside skin of the fibreglass to prevent water absorption from the inside out. Andy (aka Mr Dust attacked this job with a decent supply of sanding discs). After sanding came cleaning, to remove the dust generated by the sanding, and after this came cutting since the glass cloth was provided in a single full-width 10m length. The final preparation stage was to cut all the peel-ply to cover the glass cloth....
Because the areas we needed to glass were large and the boat had restricted airflow, the resin was curing very fast inside the boat and so it proved impossible for us to glass the whole bow in one attempt. We decided to break it up into 4 separate areas so that we could apply the peel-ply and paddle-roll sufficiently to remove any air bubbles. This meant it took longer because of the cure time for each section but it meant a quality job.
Next up were the moustache-shaped plywood ribs which would extend the existing transverse rib to meet the side of the hull. Because of the stringer along Mini Skippy's chine, fitting the plywood pieces involved notching the stringer (but not damaging the hull) and also notching the plywood piece before finally being able to slot them in place. We decided to work with templates at first to understand the exact shape we needed and then to transfer the shape onto the plywood ribs before finally bonding them in place and then glassing (routine starting to get familiar?!).
At the front of the boat and also visible in the last photo above are the foam formers for the "omegas" we were also adding alongside the plywood ribs. Together these elements act to stiffen the whole bow section and will hopefully prevent damage in the future resulting from flex in the structure.
It was now time to complete the oval inspection hatch which first involved shaping and sealing the edges of the hole before then positioning and trimming the hatch lid we had made earlier.
With all the modifications now in place, we could move to the finishing stage of the refit. Applying sealants, primers and various different paints.
More on which to follow in Part III
Credits:
Julian Adamson