The Bow Thruster Project - Part 15: Antifouling

We went to go and visit Bandit for the first time this year!

We've still got a while before Bandit is slipped back into the water but we will quickly find ourselves running out of time if we don't crack on and get the jobs done. Today we didn't really have a plan but we quickly decided to begin the antifouling process. Antifouling is a truly horrid stuff. Every time we use this paint, we always get a bad headache. But it has to be done. We got to the marina at about 1030hours and got purchased what we needed in the marina chandlery. We purchased things such as rollers and trays for the paint, masking tape, brushes, cheap boiler suits and some white spirit. Armed with our new bag of bits, it was then time to pop open the paint. We still had half a litre of some antifouling paint we had used two years ago on our previous boat when she was out. It had been sat in the garage but with a good stir, it was as good as new.

We used the masking tape and went around the whole waterline. This ensures a nice clean line after removed at the end. Then we got straight to painting and quickly used up the half litre of paint on the waterline, using a smaller paint brush to apply it as a roller was too big and we didn't want to get any paint on the hull as it's a pain to then remove. I headed over to the chandlery again and purchased a new 2l tin of antifouling. We have always used International Boatguard EU in the colour Navy as it really does do a good job and the colour never fades, unlike other antifoulings we have tried previously.

Then it was time to move onto the underside. This is always the difficult bit to get to and Bandit's hull was no exception. In fact, it was harder to roller the paint on because of the plane lines on the hull. Our Fairline had these but they didn't stop us using the roller. Instead, we had to use a brush on the bits that the roller would not get to.

The transom was somewhat difficult to paint too. We masked off the inch gap around the transom shields for the drives to ensure that the Trilux paint on the drives did not come into contact with the copper-based antifouling paint. I forget the scientific details but I know that they should not touch. Becuase Bandit is quite a big boat, she was not able to be hauled all the way out of the water. This means that I had to get some wellies on and go wading in order to paint the transom.

Something we've decided is that the antifouling line at the stern is far too high. Where the gel coat had been sanded down, we can't bring that line down. It would mean having to get the gel coat redone and that's expensive. So instead we will raise the line from the bow up slightly to even it out a bit. The waterline at the bow is only just above the water so it needs bringing up slightly anyway.

In total, there's one good thick coat of antifouling on the underside of the hull and three on the waterline. There's also one coat on the underside of the trim tabs (we left the top of the tabs polished stainless and won't paint them). We will paint the drives with International Trilux paint in the colour Penta Grey this coming weekend.

She's looking a lot neater now! We're getting there :)

On another note, we've looked at the leaky hydraulic hose on the starboard drive and concluded that it won't be impossible to change it with the drive installed. We had thought that the drive needs to come out in order to replace the hose but it looks doable as is. We will have another think about it and decide whether we do it now or next time. The leak is bad and does need replacing but we really are running out of time now. We will make a decision shortly.

Starting the antifouling at the bow and on the waterline
Antifouling the transom and raised the port drive to look at the hydraulics without causing another leak on the starboard side
Job done!
Job done!
Bow thruster tunnel antifouling and Side Power Q-prop reinstalled
Transom and Eltrim actuators antifouled - now to paint the outdrives


  1. Applied one thick coat of antifouling to the hull underneath
  2. Applied three layers of antifouling on the waterline
  3. Applied one thick coat of antifouling to underside of trim tabs
  4. Applied two thick coats of antifouling to transom and bow of the boat
  5. Reinstalled magnesium anodes to trim tabs after polishing
  6. Looked at the leaky hydraulic hose and will make decision about replacing it shortly


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