Hard Antifoul

[Stemar]

The hard work is almost complete, so it's time to think about paint.

Jazzcat lives on a drying mooring in Portsmouth Harbour, so she spends a couple of hours every tide sitting in the mud. I've never found eroding antifoul to do anything, so I'm resigned to scrubbing off a few times a season, and I'm hoping a hard antifoul will give some protection and not wash off after a couple of jet washings.

My plan is a coat or two of primer plus two coats of hard antifoul. Any recommendations as to which might work well? Or should I just go for the cheapest of the Seajet/Hempel/Jotun or whatever that I've actually heard of?

 

[Boathook]

Go for the cheapest and report back later in the year and end of season as to how it has worked.

 

[Snowgoose-1]

The hard work is almost complete, so it's time to think about paint.

Jazzcat lives on a drying mooring in Portsmouth Harbour, so she spends a couple of hours every tide sitting in the mud. I've never found eroding antifoul to do anything, so I'm resigned to scrubbing off a few times a season, and I'm hoping a hard antifoul will give some protection and not wash off after a couple of jet washings.

My plan is a coat or two of primer plus two coats of hard antifoul. Any recommendations as to which might work well? Or should I just go for the cheapest of the Seajet/Hempel/Jotun or whatever that I've actually heard of?

£89 Hempel Hard 2.5l
£110 International Ultra 300 Hard
There are others but probably look expensive.

I have used Hempel Hard for a number of years now with good results. Two thick coats lasts two seasons. You may need to shop around for best prices.

 

[Stemar]

Thanks,

Supplementary question: How much should I allow per coat?

Jazzcat's an 8m Catalac, a fairly heavily built catamaran with a beam of just over 4m and a draft of 75cm.

Edit: corrected beam

 

[Boathook]

You possibly have 14 square metres of hull to cover as a guesstimate, so it would vary as to the coverage of the antifoul.

 

[Snowgoose-1]

Just to add to Boathook's advice.

I would think that 2.5l would be fine for two good coats.

 

[dancrane]

I used Seajet on my Achilles 24, which sat deep in Solent mud twice per day for years.

As I think you said in the other antifoul thread, the mud clung to the hull and the barnacles in the mud were happy to settle on the hull. My boat had spent previous years at Fareham (state of antifoul unknown) and my first summer with her (2019) in the Itchen mud. Getting the barnacles off before relaunch in March 2020 was days of unpleasant toil...

...but despite selling the boat in September 2020, I kept an eye on her for the new owner for 12 months before he could ship her to Germany. During that year the boat was unused, and when she came out in September 2021 I was surprised how easily the chaps with jetwashers shifted the barnacles.

Obviously the patch of grey there is the un-jetwashed area behind the hoist strap. But below the waterline is clean blue, given 15 minutes with the jetwash, after 18 months in grotty Solent tidal river mud. The keel was rough as can be and I'm not surprised it couldn't be cleaned.

So even though nothing will keep a hull spotless if it's parked in mud, the not-too-costly Seajet prevents the critters getting an immovable grip, assuming that when the boat's high and dry, you're prepared for a work-out with a stiff brush, or much better, if you have a jetwasher.

 

[Farmer Piles]

I have used the Hempel for a couple of years now and it worked well. That said, I was in my local chandlers this week and he reckoned that the Seajet has the edge down here in the Fal.
My cunning plan is to use the Seajet, also a bit cheaper, but I have a bit of Hempel left over from last year and to use that somewhere below the waterline for comparison.

 

[Stemar]

Must admit that I like the price of the Seajet stuff.

Does anybody know what the Thinner A is? Not sure if I need any, I don't plan on thinning it, but I'd hate to pay £15 for what is effectively just white spirit!

 

[Snowgoose-1]

Thinners no1 is usually white spirit.
Thinners no 3 is usually antifoul Thinners

 

[dancrane]

BIt of drift, but I was looking last night at cordless pressure-washers. There aren't very many, and the best of them seem to be far too gutless for even the lightest work I'm imagining here - shifting fairly recent growth from an antifouled hull on occasional days when we're dried-out, which wouldn't have to be problematic or arduous for cats or bilge keelers.

Considering lots of tool manufacturers have applied multiple 18v batteries to applications where 18v isn't sufficient, it's a surprise there isn't a really high-output Bosch/DeWalt/ Milwaukee 36v or 54v jetwasher...

...most of us have the batteries from one of these makers' other tools...nice if they'd make a dedicated barnacle-detachment sprayer.

 

[Stemar]

I'm lucky my club - Hardway in Portsmouth Harbour - has scrubbing grids and pressure washers available, and power if I decide I'd rather use my own, though theirs are so much more powerful so for a few pounds, I'm not sure why I would. They were so popular locally that we've had to stop non-members using them because the members couldn't get bookings.

Blatant plug: It's a great club for DIY sailors with decent food and probably the cheapest bar for miles but, unsurprisingly, there's a waiting list to join.