This is an introduction to serious repair work for reinforcing and strengthening your boat!
I will use our current Lugger Katerina in this instance to illustrate how we rectified a lot of very bad so called ‘repair work‘ by previous owners to the inside of the hull. Looking at the nature of the damage around the centre plate casing and the trunk of the rudder housing, this corresponded with external Keel / Hull area damage. It became evident that this was caused by the boat taking to ground on a drying out mooring over a period of time, constantly banging and rolling. The centre plate had obviously loosened and was partly hanging down which stuck in and caused the boat to pivot and twist, hence the cracking up of the centre plate casing. She was not as advertised ‘in need of some cleaning up, but ready to sail’! But I am not deterred, having made this sort of repair many times, and the finished result is well worth the effort as you can see from our Dragon Drascombe fleet in the Southern Ionian.
The first job was to thoroughly clean and strip out the boat of fittings. We had already first-fixed some of JLJ’s new Iroko joinery so as to get all the fixing holes made before starting on the repair work. This is now removed, to improve access to avoid fouling the joinery with resin and to avoid having to mask it before the full spray work can commence.
Next to investigate what looked like glass fibre repairs around the rudder trunk and some loose corners of mat on the floor. When you get started the events open out before your very eyes. It was no effort at all to lift and cut out these ‘Surface repairs’
The hull surface was totally contaminated, old flaking paint, no sign of any prepping back or cleaning to provide a ‘key’ to help adhere the new resin and mat to the hull surface. If you’re going to do the job, don’t do it like this!
This led Matt and myself to investigate the centre plate area. What a mess! Both sides, the forward and aft truck areas again cocooned in masses of badly applied resin and non saturated mat, with lots of the mat standing off the casing sides. All had to be removed, prised off, cut through with a multi-tool, ground back with a sander, but all necessary before even contemplating a plan of action.
We have now got to the stage where only sound material is left. It is so critical not only to abrade back the glass/resin surface but to be meticulous in the cleaning of the existing surface of the 45 year hull which will be contaminated and oxidised with age and salt water, plus varying contaminants.
Whilst undertaking this aspect of the work we uncovered the ubiquitous issues arising around one’s centre plate pivot pin, not a pretty sight I may add. This I will cover is a separate page of How to Do It.
So, we are ready to start. This work is better attacked by 2 persons, one stippling the mat pieces with the resin whilst the other lays them up in the boat.
Number one thing to remember when you’re working with a catalysed Polyester resin is that the ideal working temperature is around 18 to 20C. This means the laminating resin also has to be at that temperature. So be very organised before kicking off to allow time for everything to come up to working temperature!
Have a working area set up near by where you can safely have you materials laid out before commencement of mixing the resin. Did someone ask what’s the calculator for? It is so important to add the correct proportion of catalyst to the pre-activated Polyester resin and we’re using the marked, graduated disposable 500 mm cups to do this.
Matt had the job of laying up in the boat. We had marked out the area of work – there is no point spreading it all over the boat, work to a plan.
I had a ‘wetting out’ board ready and 3 palette smaller boards that Matt could have beside him in the boat with just 4 to 5 pieces of mat on in an open fold.
For wetting the mat out, use a paint brush that has been trimmed to a stubby format and use a stippling action to force the resin into the mat structure. Do this until you loose the white colour of the mat, turn it over and apply again.
Be systematic when laying the mat sections, always use small strips rather than big pieces of mat, you can overlap and then come from the other end horizontally, thus giving a better build up and this gives more strength.
You will note from the video of the wetting out procedure I was doing, the similar method is used for ‘laying up the matting’. Apply resin to the area to be worked on, have the palette board ready with just 4 or 5 strip pieces to be applied, lay the wetted and saturated strip in place and stipple more resin into its surface. The next piece then overlaps the first and so on.
These pictures illustrate, firstly how important it is to throughly impregnate the mat with the lay up resin. Secondly the result is a translucent smooth effect where the matting has been applied and this has totally formed an amalgam, fully bonding with its initial layers. This is in stark contrast with the early pics of the previous repair work where the glass matting was lifting off the hull of the boat.
This is the finished result of the work around the rudder trunk. All the mat is saturated, no loose fibres sticking out and the matting has been extended up the trunk and onto the floor so giving a spread of strength.
Be aware, this is not an easy material to prepare and use. If you mix too much catalyst it will react and get very hot. Always dispose of mixed resin container cups into a steel can or bucket and not with domestic waste. Brushes and equipment must be cleaned with ‘Gun wash’ from automotive suppliers (it is also called Standard Thinners), again highly combustible so keep away from your area of work and outside the building, locked up.
This is our finished repair work before painting.
To complete our glass/resin repairs the bilge area is prepared and given 2 coats of Danboline protective paint, a very good, hard wearing bilge paint. Such a contrast to how it was!
However, there is more work to be done. Part 2 of this article deals with repairs to the hull itself.