Building And Assembly Of Hull - Garboard Sheathing & Painting

The sheathing of the backbone and garboard promoted slight feelings of anxiety at the prospect of handling what were to be large areas of glass fibre fabric, the reality proved otherwise. I prepared in a methodical organised manner trimming the fabric carefully in-situ and smoothing out by hand before applying the epoxy with a wide spatula. This I found easy to handle by not rucking or moving the fabric and effectively dispelling any trapped air bubbles. I worked quickly without rushing and achieved an excellent result.

I then applied a layer of epoxy mixed with phenolic micro-balloons to fill the weave of the fabric and flush out any variations in level where the fabric overlapped. When set, I used an orbital sander to flat the surface off before applying further filler to any indentations or imperfections. A final sanding achieved an excellent result. I cut the aperture for the outboard motor then filled up any remaining holes or imperfections in the remaining planking before sanding the entire hull, finally finishing by hand. I always aim for perfection which of course is impossible, however in doing so a very acceptable result can be achieved which, to the untrained eye looks perfect.

The only remaining job to carry out before painting is the fitting of the keel band. I decided to use a preformed radiused brass keel band for the stem followed by 3 mm flat bar 316 stainless steel for the remainder of the keel and centre board sides. I also decided to cap the sloping aft section of the keel down to where it meets the garboard. I jointed the different sections to withstand any lateral forces that may be applied. They were drilled, countersunk and screwed down with A4 marine quality stainless steel screws on a continuous bed of Sikaflex 291i marine adhesive-sealant.

The finished garboard, sheathed, filled and faired. Note the outboard

motor aperture and the stainless steel keel band - brass on the stem. 

Jointing detail of each section of stainless steel keel band.

Research revealed that the paint system required was to prove more costly and work intensive than I had anticipated. I estimated that there would be periods when the boat is in the water for up to two weeks at a time. It soon became clear that a carefully planned and applied paint system would be required to withstand the rigours of immersion, particularly in sea water. I chose to use Hempel’s paints. Studying their on line product data together with advice given by their technical department, I decided on the following regime. Firstly I applied a sealing coat of Hempel’s Light Primer, a two-component epoxy high build solvent based primer, thinned with the specified Hempel’s thinner by a ratio of 20%. I then applied a further three coats thinned only slightly to assist application. I lightly sanded down between each coat with a very fine paper then sponged down clean to remove any fine particles. I then applied masking tape at 100 mm above the designed water line, measuring up from the jig then joining the marks with a laser level. Another coat of Light Primer was applied and whilst still tacky a coat of Blake’s Under Water Primer. Then followed three coats of True Blue Hempel’s Hard Racing Antifoul, finished by a white 50mm wide band of Hempel’s Hard Racing Boot Top. I also applied the same paint regime to the inside of the centre board case. From the Boot Top up I applied three coats of Hempel’s Brilliant Gloss finished approximately 50 mm from the gunwales to allow for the good adhesion of further woodwork. After completion of the boat I will paint in un-painted or damaged areas before re-coating the planking down to the Boot Top.