Blacking frequency

[Top cat]

I know this is a bit like asking "How long is a piece of string" but I'm intersted in people's opinion and experience of how frequently they have thier boats blacked. Do you measure it in elapsed time or hours of use, time spent ice breaking?

Our boat had two coats of bitumen blacking three years ago. Last summer when we were on clear water it looked OK but you never really know till you scrape it.

So what's the consensus every other year or longer? What's worked for you?

 

Thanks

 

Top Cat

[NB Lola]

When I first got our boat it was clear from the survey that the previous owner had not blacked it often enough. So, we had it taken out and blacked. 12 months later it was hauled out again and the blacking need going over again. 12 months later, hauled out again and this time the blacking was in good order but as it was out we did it again, three coats of bitumin. This time it will be 18 months since the last blacking. Observation shows the waterline blacking still looks good but it will be hauled and re-done. I guess I am going to settle for 18 months as hauling also allows a good inspection of the nether regions.

[Leo No2]

2 years for me because I then have the opportunity to look closely at other parts of the hull that I cannot normally see. This year (October) we discovered little blisters in part of the blacking which you could not see even on clear water (top of the Basingstoke and it is very clear there). The little blisters had done no damage and were caused, we think, by the previous blacking company only putting on one coat (3 promised) and putting it back in the water when it was perhaps still wet - too late to go back and complain I am afraid. If I had left it another year I don't know what damage may have happened. OTOH there's a boat in Stoke Bruerne that's not been out for a full five years and is still floating but it does look as if it hasn't been out. I am advised that two part epoxy blacking will last 10 or so years but I'd still want to see the parts that I can't otherwise - trying to find something to rhyme with Hienekin but it's too early on a Sunday!

[Québec]

I suspect there is no consensus, though I reckon if there was one it'd be something like not less than two years, no more than four. It'll depend on the state of the blacking. When we bought the boat the blacking had been done by the brokers at their marina. It was a poor job, and was breaking up within the year. We then did it ourselves and 30 months later it's still in pretty good nick except, as might be expected, along the waterline, so we're going to re-black it in May, and will look to see how much, if any ,of the current blacking can reasonably be left on.

 

Others will no doubt have their own views.

[The Pipe]

2 pack epoxy when new 10000 miles god knows how many locks repainted and re-blacked after 12 years very slight pitting in one spot. Anodes also changed after 12 years as well. She's blacked to the gunnel, no paint on the hull.

In those 12 years the boat came out 3 times just to have a look and we did nothing.

Make your own judgment on how often you should be blacking and consider the quality of the product and the application.

[Rod a mod from Tod]

Ours looks like it is in need of doing, just coming up to 3 years. Our first blacking after being done post survey.

 

Hope OP doesn't mind slight de-rail but i am wondering what sort of preping the steelwork may need. Most yard advertise power wash but is that enough. I notice at the front of the boat were we have rubbed blacking off entering lock etc we are down to metal which rusts over. Do these areas need a good wire brushing or something similar before blacking.

[The Pipe]

Ours looks like it is in need of doing, just coming up to 3 years. Our first blacking after being done post survey.

 

Hope OP doesn't mind slight de-rail but i am wondering what sort of preping the steelwork may need. Most yard advertise power wash but is that enough. I notice at the front of the boat were we have rubbed blacking off entering lock etc we are down to metal which rusts over. Do these areas need a good wire brushing or something similar before blacking.

Total abrading of hull to give a key and all corrosion removed.

[Top cat]

Ours looks like it is in need of doing, just coming up to 3 years. Our first blacking after being done post survey.

 

Hope OP doesn't mind slight de-rail but i am wondering what sort of preping the steelwork may need. Most yard advertise power wash but is that enough. I notice at the front of the boat were we have rubbed blacking off entering lock etc we are down to metal which rusts over. Do these areas need a good wire brushing or something similar before blacking.

Thank you for raising that, a good point, one I will raise with the boatyard.

 

From what I'm reading here it looks like it's time we got it done.

 

TC

[Guest]

I've always understood at least every 3 years ideally definitely never more than 4 but I know some boaters who do their boats annually in the spring of every year.

 

I also know of boats that haven't been done for 10 years and are still afloat! - but gawd knows what they are like at and below the waterline.

[Captain Fizz]

I tend to go for every two years.

We are blacked to the gunnels so are able to touch up above the waterline as required

[Ex- Member]

2 pack epoxy when new 10000 miles god knows how many locks repainted and re-blacked after 12 years very slight pitting in one spot. Anodes also changed after 12 years as well. She's blacked to the gunnel, no paint on the hull.

In those 12 years the boat came out 3 times just to have a look and we did nothing.

Make your own judgment on how often you should be blacking and consider the quality of the product and the application.

 

Hi Jim

 

That's good to know, we've recently applied 6 varying coats of Jotun 2 pack epoxy, the application rendered is said to last 14 years barring scrapes/damage so it seems your coating performed as well, can you recall how many coats?

[Paul C]

We were advised, every 2 years to check the underwater hull gear and every 4 years for our 2k blacking.

[The Pipe]

The Dog House, on 12 Jan 2014 - 11:25 AM, said:

I've always understood at least every 3 years ideally definitely never more than 4 but I know some boaters who do their boats annually in the spring of every year.

 

I also know of boats that haven't been done for 10 years and are still afloat! - but gawd knows what they are like at and below the waterline.

Perfect in my case.

[Guest]

Perfect in my case.

 

Sorry yes I wasn't being clear - the boats I was referring to have been done with nothing more than std. blacking - not the stuff yours has been done with.

[The Pipe]

Julynian, on 12 Jan 2014 - 11:49 AM, said:

 

Hi Jim

 

That's good to know, we've recently applied 6 varying coats of Jotun 2 pack epoxy, the application rendered is said to last 14 years barring scrapes/damage so it seems your coating performed as well, can you recall how many coats?

3 coats when built and another 3 coats when re-blacked most of which went on top of the first lot which was abraded to provide a key, it takes quite an effort to abraid 2 pack to get a key it may have been cheaper to have shot blasted back to bare metal.

When I get around to shot blasting the boat in Holland to remove all the filler and turn it to what was described as an "old honest boat" i.e. with dents. I may consider something like this stuff.

http://www.leighspaintsonline.co.uk/epigrip-m922tg123-two-pack-epoxy-glass-flake-38-p.asp

 

Edited January 12, 2014 by Jim Evans

[Ex- Member]

3 coats when built and another 3 coats when re-blacked most of which went on top of the first lot which was abraded to provide a key, it takes quite an effort to abraid 2 pack to get a key it may have been cheaper to have shot blasted back to bare metal.

 

Yeah it's a damned hard paint that's for sure. I would have done as you did, if the original 2 pack was applied to a shot blasted surface, I imagine it would have been on a new build anyway.

 

We were lucky with the weather so had a barrier primer on within 2 hours of the shot blaster finishing. A further coat of jotun primer + 2 josamastic 87 + 2 hard top. I'll probably have the boat out in 5 years for a quick look unless some dramatic occurrence happens below the waterline prior to that. I've had a few quite heavy scrapes and some paint is marked above the waterline, on close inspection it hasn't actually noticeably removed any paint and the marks can be rubbed off.

 

Brilliant paint, I'm not at all surprised your's lasted so well.

[Timleech]

Paint makers recommendations that I have seen are 2 years for bitumen paints, 3 years for tar paints. For 2-pack paints, it's really down to whether there has been any abrasion to break the paint film.

 

Tim

[The Pipe]

 

Yeah it's a damned hard paint that's for sure. I would have done as you did, if the original 2 pack was applied to a shot blasted surface, I imagine it would have been on a new build anyway.

 

We were lucky with the weather so had a barrier primer on within 2 hours of the shot blaster finishing. A further coat of jotun primer + 2 josamastic 87 + 2 hard top. I'll probably have the boat out in 5 years for a quick look unless some dramatic occurrence happens below the waterline prior to that. I've had a few quite heavy scrapes and some paint is marked above the waterline, on close inspection it hasn't actually noticeably removed any paint and the marks can be rubbed off.

 

Brilliant paint, I'm not at all surprised your's lasted so well.

It will last I had mine out 3 times thinking it might need doing and just said why bother it would be a waste of time and put it back. After 12 years she was still good and the bits I've knocked of were protected by the anodes, I question if anodes are actually worth while with 2 pack as they only reduced to about 2/3 of original material in 12 years, we replaced them anyway. I could have just patched in bits but I had an extra guard welded on and other changes and with the re-paint you might as well tart everything up.

[frangar]

My boat was grit blasted and painted including the 6mm base plate with comastic 22 years ago on the advice of my surveyor...two pack wasn't really understood by canal based yards then! The boat is now 31 years old and on the last hull survey a couple of years ago hasn't lost anything more since my purchase survey....I recoat with comastic every two years....we are lucky at debdale in that they have a ultra high power pressure washer and good access to the baseplate.

 

Cheers

 

Gareth

[peterboat]

Hi same here every 2 years with comastic after a good pressure wash. I apply 3 coats then leave 48 hours or more before putting back in the water

[Bee]

Anodes and epoxy, I have 2 pack on the hull and to be honest I don`t think the anodes really do much except for the little ones on the rudder and the ones by the bronze prop, as for keying the surface of existing two pack, I think it might be best to try an orbital sander, that's what I will try next time. wire brushing seems to polish the stuff.

[Chalky]

The hull was grit blasted when new and coated with 2 pack epoxy. It comes out every 4 years and each time there's no change in the hull. Anodes were half used up last time (after 8 years) so the coating seems to be working.

[Detling]

Slighly off topic but related .

 

Anodes are there to protect against electrolytic action between dissimilar metals. They do not prevent rust, but do prevent the propeller eroding by glavanic action, they erode first and they also protect things like bearings which also are not steel and being more noble would corrode first. Iy you want to see what corrosion can occur wrap a bit of copper wire around a shackle and hang it over the side for three months, then see whats left of the copper wire if any. That is why you use steel/galvanised wire to secure a shackle pin.

[luggsy]

what is the cost of 2 pack, say on a 58ft narrow boat ?

[Ex- Member]

what is the cost of 2 pack, say on a 58ft narrow boat ?

 

Depends on how much you use, there are several different application you can choose to do. I can give you a guide in relation to ours.

 

60 f/t x 10/6 wide beam, all Jotun 2 pack. 1 coat barrier primer 1 coat primer, 2 coats jotamastic 87 and 2 coats hard top Paint cost £700 expected protection 14 years.

 

Shot blasting £450

 

brushes rollers trays £50

 

Total cost DIY £1200

 

Shot blasting is highly recommended. The Jotun website has lots of info. We purchased from this company. https://www.smlmarinepaints.co.uk/home they were the best price at the time June last year.