How to remove algae and what antifoul to use

[Adetheheat]

How do I remove small amounts algae from hull? Would a pressure wash do it? With algae remover fluid I suppose I just spray it on then scrub off the algae?
For antifoul paint are they all similar ? It's just that some are 90 pounds a tin but others are 50 pounds.
Thanks

 

[ChromeDome]

A high pressure washer with a rotary  nozzle very soon after lifting out, should do. As in before it dries out.

At least do this before considering all sorts of miracle chemistry at fantasy prices

 

[AndrewB]

Yes, pressure washer. But if you are cheapskate, the stuff can just be scrubbed off, either out or in the water (its mostly close to the waterline). But if its barnacles, you will have to scrape. (It's odd how one year the fouling is bad, another it is light. Sometimes weed, sometimes barnacle, sometimes worm).

There are different types of antifouling, with different prices. Cruising yachts tend to use self-eroding, which is at the cheaper end of the scale, even so big variations between brands. One can only assume that cost reflects effectiveness: but in my experience, that is a maybe. As a general rule, the more you use your boat and take it to different waters, the less the fouling. That's my policy, use the cheapest brands and keep the boat moving.

Someone will be along soon who swears by Coppercoat, an expensive but 'once in a lifetime' antifouling. Judging by the remarks here, it seems to work for some people, but not for others.

Given the frequency that the issue of best antifouling arises, and the variety of opinions, you should definitely do a search here on this topic to look at older threads on this subject.

 

[LittleSister]

AndrewB mentions there are different basic types, two of them, of antifouling -
1) Self- eroding antifouling is fairly soft, and works by gradually being worn away to reveal fresh material in order to be effective. Mainly used by cruising sailing yachts and slower motorboats (it's not good for high speed craft). Reduces, but does not eliminate, the gradual build-up of old antifouling on the hull, which adds weight and friction).
2) Hard antifouling is hard, and works by the 'poison' in the paint gradually leaching out. Tends to be used by racing yachts and fast motorboats. Smooth hard surface gives less friction and can tolerate high speeds, but the old paint has to sooner or later be removed (grim job) to avoid build up of old paint.

There are versions of the above for sea water and for fresh water (inland waterways).

Note that anti-fouling is toxic to you and to wildlife. Avoid eating, smoking etc.; avoid as far as possible) getting it on your skin; and definitely do not dry sand it to remove old anti-fouling, don't dump paint on the ground or into water.

You need to apply a suitable underwater primer coat first if you are changing from one type to the other, don't know what the old type is, or you are applying anti-fouling to bare GRP or other hull material. You need to remove any flaking or bubbled old antifouling (and prime any resulting bare patches) before overpainting. Follow instructions about temperature, how many coats, etc., and minimum and maximum times before the boat is put in the water.)

In terms of which type/brand, I'd recommend that in the first instance you avoid the very cheapest 'bargain' brands, stick to well known brands (e.g International, Hempel, Jotun) and buy their basic, rather than premium versions. No anti-fouling is completely effective, the type and amount of fouling varies place to place and year to year. Ideally ask people in the area you keep/use your boat in (via this forum or talking to locals) what they use/recommend. See how you get on, and you might be satisfied or want to try something different next year..

 

[Fairlineboat]

Use a high pressure hose to get the algae off and depends where you are and what money you want to spend really depends on what antifouling. When I wanted to do my boat I checked with this website. The great UK antifouling test for cruising yachts - Practical Boat Owner and also asked in my local marina shop what they recommended. I also would use Antifouling Primer.