Anti Fouling on a canal - yes no or need to read up?

[symondo]

Im just curious...

Ive only experience of anti fouling in salt water

is anti fouling needed in fresh water - is it any different?

Im also wondering if there are rules as to the type of anti fouling used on a canal system?

Specifically the caledonian canal.

 

[Trundlebug]

Antifouling is needed in fresh water, but it lasts longer on the whole. I tend to haul out every 2 years especially if (as is usually the case) I've done a mix of cruising fresh and salt water areas.

Without antifouling you will get small fw barnacles and long slime weed.

Boats that constantly alternate between fw and sw don't need to antifoul because the types of growth in each area don't like the other type of water. Generally a light scrub sorts it out.

 

[Quandary]

My berth is on the Crinan Canal (Scottish Canals, same rules as Caley, ie none.) I use Gaelforce, (rebadged Flag) cheap stuff but does ok, we spend about 8-10 weeks at sea so I do renew it each year. I suspect I could manage without anything. The advantage the Caley has over the Crinan is much purer water, here with the peat white AF goes brown very quickly so we use dark colours. For the saildrive leg I use lanolin wax (Propshield) which lasts about three years, the prop itself is polished to a shine and keeps itself clean.
A much bigger issue is anodes, zinc turns to an ineffective passivated coating rapidly in fresh water, while magnesium dissolves in about three to four weeks in the sea, best and most popular would be aluminium but the range of special shapes is limited so I have to use zinc supplemented by a zinc hanging anode wired back to the leg which I clean with sandpaper every 3-4 weeks. The little zinc anodes on the prop still go as quickly as in salt water but the leg anode lasts for ever under its coating.

 

[Bru]

Never, technically speaking, antifouled a canal boat in 20 odd years on the cut

Mind you, we did paint the hulls with bituminous black paint which was pretty foul stuff so I suppose really we did

Then again, we only used bituminous paint 'cos we couldn't get traditional coal tar any more!

On the early GP boats we owned, we didn't even have that protection and I don't recall getting any barnacles or other growth of that nature. Just a fringe of weed around the waterline which the ducks would peck off, usually about 4:30am in the morning for breakfast which could get rather annoying!

 

[NormanS]

I used to be six months at Sea, then six months in the Caley Canal. I still antifouled every year, but didn't get any fouling in either.

 

[Momac]

My experience on fresh water (R Trent) with occasional salty trips suggests very little in the way of antifouling is required . So best use harder antifoul which will probably remain looking okay a long time.
Something like this..............
https://premiermarinepaints.co.uk/buy/premier-one-can-semi-hard-antifouling-yacht-boat-paint/13
.