How to get rid of deck algae?

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teensailer

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I have been trying to clean the decks of my joint-owned Swift 18 but there are loads of dark green/black spots all over it. So far the only thing which has worked for getting it out from in between the anti slip is a metal scourer, Even that doesn’t work completely and is not going to manage for the whole deck and cockpit.

So I wondered what other people use for this kind of problem?

Thanks
 
jet wash will get rid in a very satisfying fashion. itll also uncover lots of leaks you didn't know you had. don't point it at obvious weak points.
patio magic will kill it all but wont clean the deck.
i tend to do the (gentle) jet wash route then give it a bit of patio magic after. seems to do the job.
 
Dellquay13 said:
As long as the boat is ashore, the run off isn’t good at all for aquatic life.
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I have used it on teak and taken care not to apply excess. In any case, it is better to paint it on, eg with a deck brush, rather than spray it.

Paint it on at the indicated strength, say 1:5 when there is no risk of rain. You may not see much change for a few days until the green or black washes off at the next rain. It seems to be safe to use on fabrics such as boat canvas.
 
Thanks for the replies. I wasn’t sure the jet wash would do it as it’s not super powerful and it takes a good ten minutes with the scourer to remove a mug size area. Considering the boat sat untouched and uncovered in a Scottish garden for untold years before we got her I think it’s pretty firmly stuck.

Not heard of the ‘patio magic’ before, is that something I could buy from the local gardening centre? I will try to use the jet wash first but it’s been temperamental recently so I didn’t think to use it.

I also wondered if a mould killer spray would do it if left to soak and scrubbed off with a stiff brush?

Cheers
 
teensailer said:
Thanks for the replies. I wasn’t sure the jet wash would do it as it’s not super powerful and it takes a good ten minutes with the scourer to remove a mug size area. Considering the boat sat untouched and uncovered in a Scottish garden for untold years before we got her I think it’s pretty firmly stuck.

Not heard of the ‘patio magic’ before, is that something I could buy from the local gardening centre? I will try to use the jet wash first but it’s been temperamental recently so I didn’t think to use it.

I also wondered if a mould killer spray would do it if left to soak and scrubbed off with a stiff brush?

Cheers
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I used to use something called 3 in 1 mould killer but they changed the formulation and it stopped working and so changed to Patio Magic. There are various similar formulations, especially the stronger Boracol, but Patio Magic is readily available at B&Q or garden centres. From what I remember of my school botany, mould and algae are different, but PM seems to work on both.
 
teensailer said:
Ok cheers, I will retry the jet washer then if it doesn’t work, I’ll go buy some patio magic
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Patio Magic is widely used by a lot of boat owners - including me for past 15 years - and works very well. Paint on (with gloves etc) when there is a day or so of dry weather (like now) and leave for a week and most should be gone.
Easily available from B&Q, garden cans or online.

Ca canny with a jet wash and an old boat, as if powerful enough to remove dirt can also remove bits of boat you don’t want removed.
 
If all else fails some swimming pool chlorine in a liquid form is brilliant for cleaning patios etc. just pour on and use a yard brush to spread -never used on decks but a I guess a 10litre canister would solve issues pdq.
 
teensailer said:
. . . So far the only thing which has worked for getting it out from in between the anti slip is a metal scourer, . . .

Thanks
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I would have thought that a metal scourer will leave a host of tiny scratches in the GRP surface which will subsequently collect dirt, and hence be harder to keep/get clean in future.

I can't add to the previous advice on potential potions and lotions for the task.
 
To clean, first use the jet washer. At the start of the winterseizoen wash the (cleaned) deck with a high concentration of baking powder ( sodium bicarbonate) in a manner that leaves behind the residu. Then cover the boat, and enjoy winter close to the woodburner. This method will prevent algae and the flush off will not harm nature in any way. You May use it in your watertank as well. It kills bacterial and algae, is cheap, and safe for yourself as it is body-own.
 
Me ? Biggest bottle of Mould / Algae killer I can get in Garden shop .... dilute as indicated ....

Pressure wash then >

Spray / brush / roller it on liberally all over ..... leave it to work.

Few days later pressure wash again ... repeat solution to get last remnants off ...

Pressure wash later ...

Oxalic acid to then remove any other marks / stains ... pressure wash after.

I've never painted on and left it ... but may do this next time ... I was always aware of people with bare feet on the deck and if wet - wondered if it could be bad for such feet ?
 
ashtead said:
If all else fails some swimming pool chlorine in a liquid form is brilliant for cleaning patios etc. just pour on and use a yard brush to spread -never used on decks but a I guess a 10litre canister would solve issues pdq.
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Sold online as Sodium Hypochlorite and not overly expensive. I use it on the inevitable winter green that appears on a north facing white wall and it works a treat.

Works a treat too on grp surfaces, but don’t get it on your canvas work. I dilute at approx 5:1. Just apply, go for a coffee, return 30 mins later and hose off.
 
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