The act of antifouling

[Rum_Pirate]

I have my trimaran on a trailer at the moment.

It has been anti fouled before and the hulls are clean, well very little of the original antifouling is left.
May give them a wipe down with acetone.

How do you maintain the line of the antifouling to get the masking tape in position?

Do you have a preference as to the make and width of the masking tape?

What is the best way to set about prepping and anti fouling the hulls?

 

[rotrax]

If you Trimaran is too sit in the water foe extended periods it will need AF.

If it will be mostly on the trailer when not sailing, why bother?

 

[Rum_Pirate]

If you Trimaran is too sit in the water foe extended periods it will need AF.

If it will be mostly on the trailer when not sailing, why bother?

I am too lazy to lower mast and haul out and relaunch each week.

So in November it goes in and comes out in end of June for hurricane season, thus needs anti fouling.
The heat here really encourages the growths on the hull.

 

[srm]

Some hulls may have a scribed line moulded in to the gel coat for the waterline. Otherwise lightly tack the masking tape using the old antifouling as a guide, adjusting by eye until you like the line. Then push the tape down firmly along the edge you will be painting to.

No preference to brand of tape, whatever the local store has. Narrower is easier to keep straight on the curved surfaces of a hull, wider protects the topsides better from the paint. Remove the tape as soon as you can, if left for a day or so it can be difficult to get off, and after a week or more becomes an almost permanent feature. A few bits that had been left on for a couple of weeks during a multi coat epoxy application were still on the hull after almost a year of sailing. I thought the sea would remove the last few difficult pieces but no such luck.

 

[Chiara’s slave]

The boat is quite easy to tape up, very little 3D curvature. Though remember that you’ll be using nearly 60 metres of tape, a 50m roll WILL run out, you can imagine how I’m so sure? You’ve got a reasonable looking waterline there, I liked to do the floats first, then open up, chock the floats, pull the trailer out and do the main hull. Wind the jockey wheel right down, chock the float transoms tightly, wind the jockey wheel right up, chock the float bows and pull the trailer clear with the wheel at half height.

 

[johnalison]

I've never taped or antifouled a trimaran, and I don't think I want to. My a/f edge is usually just above my eye level, so it is fairly easy to run about 5' of tape from the part stuck to the boat and smooth it onto the boat with my eye more or less in line and get an accurate mark. It is easier to do it in long sections rather than in short bits. I use blue tape because I sometimes have to leave it a few days, but generally narrower tape is easier to curve.

 

[Chiara’s slave]

I've never taped or antifouled a trimaran, and I don't think I want to. My a/f edge is usually just above my eye level, so it is fairly easy to run about 5' of tape from the part stuck to the boat and smooth it onto the boat with my eye more or less in line and get an accurate mark. It is easier to do it in long sections rather than in short bits. I use blue tape because I sometimes have to leave it a few days, but generally narrower tape is easier to curve.

I’ve done it more than twice, as the saying goes. Its the sane as any other boat but 3 times as much tape, and lower. The wetted surface area is usually less than other similar length boats so the actual time with a roller is a bit less. The pratting around with the trailer is probably no slower than allowing yours to dry, then moving the props, or dropping one at a time, with the paint drying in the sun. Best of all, no boatyard staff involved at any time, recovery, propping or relaunch.

 

[Boathook]

I would just follow the existing antifoul line. It does seem from the picture that there might have been a boot top or is it just the waterline ?
Regarding masking tape I would use a reasonable quality one as they can be left on for a few days (in the UK) and still come of cleanly.
Allow enough tape as you do waste some around the bows and sterns.

 

[Bodach na mara]

You don't say what type of antifouling you are using, but I have never used anything other than water to wash the hull before applying new stuff. Acetone is not advisable. It's expensive. It evaporates too fast to do anything. The vapour is very unpleasant.
So for washing the hull I use two squeezy mops, one to wet the hull and the other has scotchbrite pads glued on to abrade the old antifouling. If a hose is available you can dispense with one of the squeezy mops.

 

[Rum_Pirate]

I would just follow the existing antifoul line. It does seem from the picture that there might have been a boot top or is it just the waterline ?
Regarding masking tape I would use a reasonable quality one as they can be left on for a few days (in the UK) and still come of cleanly.
Allow enough tape as you do waste some around the bows and sterns.

No boot top, so simpler.

 

[Boathook]

@Rum_Pirate just follow existing lines.

 

[Rum_Pirate]

@Rum_Pirate just follow existing lines.

Plan to do that but was thinking of adding a 1mm or so to ensure that the original antifouling does not 'peep' out.

 

[Chiara’s slave]

And pay some serious attention to that rudder blade. Any roughness will promote ventilation. That is truly alarming whilst trying to bear off under pressure.

 

[Rum_Pirate]

What is the active ingredient in your anti fouling?

The one I bought has Cuprous Oxide 33.6%

 

[Chiara’s slave]

The warning on the can is promising.

 

[Daydream believer]

I do not bother with tape. I can cut a line following the old paint very easily. I recall one year doing one half of our club committee boat. I had cut the paint to the line before they had finished taping the other side. Even then they had leeching under the cheepo tape. But then I have cut enough georgian window panes in over the years to learn how to do it.

 

[Cardinal]

I find that „frog“ tape works very well and sticks well but peels off easily with no leeching of a/f apparent.

 

[LiftyK]

Use blue painters tape. 3M brand is good. The reason is that it removes easily. I once left regular tape on for longer than I should have done and it took forever to scrape off the residual adhesive. Never again. With the blue tape, I'm relaxed about antifouling.

 

[Neeves]

Rum Pirate - my romantic ideas of your location is somewhere with an everlasting warm climate. A bit like a 365 Sydney.

I have a suspicion you might find sourcing fancy expensive tape something of a challenge.

If it is warm than the AF will dry quickly - and our practice with quick drying paint is to use the cheapest masking tape available, we buy a pack of 6 rolls. As mentioned you will use a lot of tape - buying cheap tape means you can buy a bit extra - running out of tape is a pain. Josephine applies the tape by eye and I apply the AF with a roller. I can get 2 generous coats on a 38' cat in a day and at the end of the day we remove the tape.

If you leave cheap tape on overnight and if it rains or is subject to dew then when you come to remove the tape - the adhesive stays on the hull and is a devil to remove (turps -which also removes the new AF).

I'd suggest pushing the 'waterline' up as if you are leaving the tri in the water than you will get scum line and a higher 'waterline' will hide the scum. We simply add a black boot top - with a black AF (and red AF for the hull).

So...Josephine masks the top of the boot top, I roller the boot top, 2 coats (the bottom edge does not matter - it will have tape for the edge later and the hull AF will overlap, Josephine waits till the boot top is touch dry and applies the tape for the hull AF - I roller paint the whole underwater hull. We remove all the tape at the end of the day. If we have any hull AF left at the end of the day - extra on the water line and leading edges of rudders and keels.

Josepheline always looks very smart at the end of AF - its all very satisfying.

If its very hot - paint the hot sides of the yacht early in the day trying to paint the sides that are in the shade.

Sea Hawk have a decent reputation.

In general - better paints have more copper. If you skimp on coating thickness (a common issue, people tend to eke the paint out) the paint will not last long. Its not a guarantee but more expensive paints offer better performance than cheap ones. Most of the 'top of the range' from each of the major suppliers are similar in performance. Most companies offer a paint coverage guide - its really crude - but check it out and if you find you paint is lasting longer, you are using less than recommended when you apply, than suggested - your coverage might be a bit thin.

Many here would suggest they are getting a 2 years AF life - but it varies, a lot. Keeping your yacht next to a floating reef (or mooring minder) is a recipe for early fouling.

Jonathan

I note Chiara's comment about hard AF. Ablative paints, I think, are designed around sedate sailing and your sailing might be a tad faster. An ablative paint might not last too long if you scream about the waters at 15 knots. Maybe have a word with Chiara, on what they use, and ask Sea Hawk for a recommendation (that's part reason they have a technical department).

 

[Chiara’s slave]

Hopefully thats a hard racing antifoul? That way you can scrub it without scrubbing off the paint. On your boat that is a pleasure to do, get your crew to help by bribing them with beer.