Hull maintenance
by Alan Scott
Having an old Hartley built in 1974 it does need some maintenance. The boat as seen several owners and has been racing for most of it sailing life. The entire cabin has been rebuilt and refurbished but the hull has not been touched much since it was built. The outside skin is also been dynal sheathed with fibreglass. The paint used to cover the hull was a Weather Shield enamel and has been touched up over the years. However, recently water has penetrated the keelson and weakened the screw holes holding the steel skid plate that was screwed to the bottom. Also leaks were developing along the second chine join around the end of the boat trailer. The water was penetrating through the paint and then the glue. There are still many boat owners with similar aged boats and so I thought it would be useful to document and discuss the repairs I am making.
The first step was to pull the boat onto its side using the mast to hold the boat down while I send it back to problem areas on the whole. Once the boat was securely held down are used to small chisel to scrape away the paint along the second chine seem. The glue in the joint was quite powdery and was able to scrape this out quite easily to about 4 mm deep. I then used Northane epoxy glue to re-glue this seem. While doing this I found some old screws that obviously been used to hold that section of the plywood down. That all practically rushed about you may use suppliers to try and pull their heads out I just broke off easily. I then use the glue again to fill the holes and make the scene secure again. See Photo 1.
The next step was to remove skid plates and try and repair the skeg. Can a cheque from nails and screws using a thin chisel. Again several nails and screws were found and were easily removed due to deterioration of the wood around them. I then waited for the wood to try and used to hand plane to try and even up the surface. It was found that was several layers of which would which had forced elimination of the wood and one major groove caused by skid damage (see Photo 2)
As there was considerable wood exposed and exposed the edge of the fibreglass. It will be necessary to seal the wood with Northane wood sealant especially those areas next to the fibreglass. Then the holes cruise will be filled by Northane Epoxy filler before undercoat is supplied.
Before in the coat can be applied the entire surface needs to be sanded back and all bumps cruise evened off so that the undercoat can effectively fill make surface smooth (see Photo 3).
With the wood areas now treated and sealed it was time to prepare the surface for the epoxy undercoat. As the hull is old it was evident that there were a number of areas with plywood is either walked a bit between the frames creating large depressions. One amidships along the second port chine and the other near the stern halfway between the skeg and first chine. These depressions were watertight but they would affect the flow of water over the hull. There are a number of ways to fix this but as my time and equipment is limited decided to use the epoxy filler to fill in the depressions. This meant a lot of sanding and refilling after about five coats of filler I finally got a smooth consistent surface even though I did not have the time to cut back the painter’s much as I’d like.
The next step was to put on the Northane undercoat. The Northane two-part epoxy products takes a while to get used to, is essential to get the right amount of thinning agent in the mix viscosity allows easy application. My first mistake was to mix too much quantity up, as it started to solidify before I finished applying the paint which led to serious runs. So the first tip is; don’t mix too much up initially or if you do fill it down with their thinning agent. This undercoat goes on very easily with a roller.
After several attempts at applying the final colour coat, I realised it was a lot easier using a fine roller then the brush over such a large area the entire hull. A good coat can be applied by brush but the mixture must be very thin which as involves applying lots of coats and extensive time taken to paint the boat. Using the roller thicker coat can be applied initially reducing time and effort painting such a large area.
To cut down costs only purchased enough two-part epoxy final colour to cover the wooded areas of the hull. This means basically slightly up the first panel below the deck. Two-part epoxy has the advantage of being and so if there were any finer holes in seam still epoxy paint should maintain a dry boat. Above the waterline used the one part epoxy or with the paint which is easy to apply broke brush or roller and much cheaper. Not waterproof but mostly above the line and so was easily applied on by brush
However, it is a lot cheaper if you don’t have to send back the paint we do it again due to the paint not drying before the heavy dew. As you can see by the pictures I cannot put my boat under the cover of the carport and I applied a colour coat too late in the evening one day and condensation overnight destroyed final finish of the colour coat requiring it to be cut back and painted again. So if you are doing work outside make sure you do all your painting in the first half of the day.
Finally, after the hull was done I was able to right the boat put it back on the trailer and finish off the last 300 meals below the deck. Course allow the boat to be put under the protection and so could be done at my leisure. This was the single part colour which was easily applied by brush make the job a lot easier.