Medina antifoul questions

[Highndry]

Sorry for all the really basic questions. First Winter as a boat owner so everything is coming around for the first time!

My Medina was anti-fouled with Blakes Broads. I understand that the key to re-antifouling it is to rub down the existing covering with 120 grit wet and dry and rinse before applying a new coat. But how much would I need for a full coat? It seems to be available in 750ml or 2.5l cans.

Also, the lifting keel looks as though it's been painted with Hammerite. Is that likely? There's no corrosion that I can see but she has spent the last several years on lakes.

 

[l'escargot]

The instructions on the back of the tin will give you coverage guidelines in square metres, just work out the rough surface area of the bit of the boat you want to paint - first time is a bit of a guestimate but next time you will know exactly how much you will need.

As for the keel, people paint boats with all sorts of things and it's often just a guessing game to work out what has been used previously. If it's sound and doing the job no problem. If you think it's Hammerite and want to repaint it, try a small test area first with the new paint to see how it goes on.

 

[jakeroyd]

Assuming it's a Hunter Medina it's about the same as my boat (Hunter Ranger 245)
2 coats of Blakes Tiger extra , applied by roller uses about 3.5ltrs.
I buy two 2.5ltr tins one year and 0n2 the next , give or take.
If you Google 'antifouling calculator' you can get a range of estimators online.

It depends also on what you buy and use.
If you were using Cruiser Uno , one 2.5 tin would do (one coat)

It's not IMHO always required to sand the old antifouling.
(if you do do not sand it dry cos it's poisonous)

If the old antifouling is thin and exhausted and reasonably well stuck to the boat you can apply antifoul directly over it.

You could also apply antifouling to the keel.
It's soft so it may wear off where the keel rubs on the keel box but that pretty normal I would say.

Opinions vary madly on the prop.
I used to just antifoul mine until I discovered it would last less than a season and then foul up , so towards the end of the season the boat would motor really slowly.

I have found (for the prop) Hempels Mille Drive to be reasonably effective.
It's an aerosol and uses a primer before topcoat system

You can also shine up your prop (really shiny with the smoothest surface you can get on the owrking part of the blades) and leave it or shine it and apply lanolin greases or specialist products.

All these processes have their Champions and Naysayers. There is probably no perfect protection for the prop.

My suggestion in your first year would be to apply a coat of Cruiser Uno , shine up the prop and go sailing

 

[Highndry]

If you rub something across the antifoul that's already on (a cloth for instance) you get a nice smear of blue dust on the cloth. Is that normal?

 

[jakeroyd]

Yes , I would say so , it's soft and will have dried out if the boat has been out of the water for any length of time

 

[Highndry]

So is there an antifoul that's designed for trailer sailers or does the very fact that she spends more time dry than wet mean I shouldn't be worrying about anti-foul anyway?

 

[Cloven]

If you rub something across the antifoul that's already on (a cloth for instance) you get a nice smear of blue dust on the cloth. Is that normal?

Yes - remember that the antifoul on a cruising boat will be self eroding so any rubbing will release some.

Where are you going to use the boat, freshwater or sea? Blakes Broads sounds like a freshwater antifoul so, unless you are absolutely sure of the previous coating and are re-coating with exactly the same, you will need a primer coat first to ensure there is no incompatibility.

I had a Medina many years ago - great little boats. You are wasting your time with 750mm tins. Its only about 20ft so I would reckon that you should get about 2 coats out of a 2.5l tin.

Obviously comments about the prop above are irrelevant as you will have an outboard.

 

[Highndry]

I'm confident the existing antifoul is Blakes Broads as the previous owner dug the old tin out of the garage to check! Checking the data sheet for the product it is rated for freshwater and saltwater application.

As to where the boat is going to be used, mostly Rutland Water but this year, now that I have some experience of sailing her accompanied only by wife/daughter, I intend pulling her down to the Orwell for a few weekends.

 

[Cloven]

I'm confident the existing antifoul is Blakes Broads as the previous owner dug the old tin out of the garage to check! Checking the data sheet for the product it is rated for freshwater and saltwater application.

As to where the boat is going to be used, mostly Rutland Water but this year, now that I have some experience of sailing her accompanied only by wife/daughter, I intend pulling her down to the Orwell for a few weekends.

Are you intending to leave the boat on the water for any length of time - ie more than a day or so? If not, then you hardly need antifoul, just give the hull a good wash off, preferably with a jet washer, when you have finished using it. On fresh water, all you will get anyway is a layer of slime which will scrub off but do it while the boat is still wet after taking out of the water or it sets like concrete.

I kept mine on a salt water swinging mooring all season so needed good antifoul. We sailed her all around the West Coast of Scotland and as far as the Inner Hebrides, Coll & Tiree.