Blacking & the relevance of the base plate

[Alan de Enfield]

4 minutes ago, rusty69 said:

70 foot boat, 2 people. Usually manage some gloss and the baseplate too (although ot appears we may be wasting time and money with this bit) 

We pay a yard to do it - maybe they extend it by a day to have a 'weekly' turnaround of their dry dock ?

Goes in Friday evening, start Saturday 7 am, comes out Friday evening and the next one slips in - pump-out dock and the next one is ready for starting Saturday 7am

[rusty69]

1 minute ago, Alan de Enfield said:

We pay a yard to do it - maybe they extend it by a day to have a 'weekly' turnaround of their dry dock ?

Could be, although I would expect the extra day at the end to give max drying time.

[dor]

41 minutes ago, Alan de Enfield said:

To do 'the job' properly takes 7 days and 3 coats of blacking.

Not only are you taking up someones trailer / dock for 7 days but you have quite a lot of labour and materials.

Whilst I cannot remember the exact order of things  this is something like (from when ours went in) This was Early June.

Day 1- 7:00am - hull jet wash and dry off, then wire brush any loose flakes, jet wash and allow to dry off

Day 2 - 1st coat, and paint any of the awkward spots around prop, up weed hatch, etc etc.

Day 3 - 24 hours drying

Day 4 - repeat of day 2 (2nd coat)

Day 5 - repeat of day 3

Day 6 - repeat of day 2 (3rd coat)

Day 7 dry-off and re launch late afternoon.

 

 

THat is pretty much what I do.   Three coats Intertuf, brushed on not rollered.  I believe the 24 hours between coats and, more importantly, at least 24 hours after the last coat before it goes into the water.

I don't two-pack as most of my boating is on the Shroppie system and the Shroppie shelf goes through two pack just as easily as decent bitumen.

Too many boatyards roller on two coats, often on the same day, then back in the water as soon as it is touch dry.  It's worth doing it yourself and take a week over it.

I've seen a lot of boats pulled out of the water, plenty with deep pitting or general corrosion on the sides, but the only boats I have seen with a problem with the bottom plate is 20+ year old boats with thin plate to start with.

[rusty69]

2 minutes ago, dor said:

Too many boatyards roller on two coats, often on the same day, then back in the water as soon as it is touch dry.  It's worth doing it yourself and take a week over it.

Agree with this. We use Rylards Premium which suggest relaunch time at 10 degrees C is a minimum of 48 hrs after final coat.

[Stilllearning]

Each to their own: I used to book the dry dock for 2 days in summer, on the first morning in the dock, pressure wash the hull almost before the dock was empty and remove the accumulated aquatic growth and mud, but almost no rust at all. This stage was the most important: a really thorough pressure wash using very high pressure and temperature removed everything that had to come off.

Wait for the hull to dry, brush off by hand any bits that needed extra attention (almost never needed to do this stage). Get the first coat of bitumen on that first afternoon/evening, leave to dry overnight. Sleep onboard, always remembering to take care getting on and off as it's a long way down.

Second day get on two more coats, leave to dry overnight, then fill the dock on morning of third day.

A roller does the job perfectly well, after doing all the fiddle bits in the corners etc with a brush.

Cheap as chips, as they say, and done for the next two years.

When sold, there was no significant pitting on a 15 year old hull that was almost permanently on shore power in a marina rammed full of other boats.

But as I said, each to their own.

oh, and I never touched the base plate

Edited July 3, 2017 by Stilllearning
Added a bit more

[MtB]

On 12/01/2017 at 09:55, Numpty said:

 

So it begs the question if and only if the base plate does not need blacking why do we need to do the hull other than for esthetics; are we just putting a surface on to scrape off again?

 

 

I think the best place to start is by thinking about what you mean by 'need'. 

There is plenty of anecdotal evidence (my own boat included) that 10mm baseplates last 30 years+ without blacking. But if you want to preserve your boat 'as new' and combat every sign of age degradation then blacking the base every year is probably a Good Idea.

My own view is that the intended life of a narrow boat from new is about 30-40 years, and if the baseplate lasts that long, it has done its job. Once your boat it that old, new fashions in boats will have arrived, the interior will be hopelessly dated, and it will be time to buy another new boat surely? 

If you are still alive. 

 

[mrsmelly]

1 hour ago, rusty69 said:

We normally 

 

Day 1.Scrape and pressure wash

Day 2. 1st coat blacking

Day 3.2nd coat blacking 

Day 4. 3rd coat blacking

Day 5.drying p

Day 6.refloat (48 hrs after last coat) 

Day 7. Get drunk and celebrate that we don't have to do it again for two years. 

 

70 foot boat, 2 people. Usually manage some gloss and the baseplate too (although ot appears we may be wasting time and money with this bit) 

Just to put a bit more interest into this. I bought a colecraft some years ago that the owner had owned for eighteen years and it had NEVER been out the water, blacked or anything so we agreed a peanuts price as both vendor and I thought it would probably need extensive plating though the waterline looked good. I took it straight up to Johnie Pinders at tardebigge for hull survey after buying it and to have any work done. The base plate and sides were all six mill. The worst pitting and wear took the boat down to 5.7 mil so nearly new and needed nowt done. Its a 1981 and still going strong with the bloke who bought it from me.

[rusty69]

14 minutes ago, mrsmelly said:

Just to put a bit more interest into this. I bought a colecraft some years ago that the owner had owned for eighteen years and it had NEVER been out the water, blacked or anything so we agreed a peanuts price as both vendor and I thought it would probably need extensive plating though the waterline looked good. I took it straight up to Johnie Pinders at tardebigge for hull survey after buying it and to have any work done. The base plate and sides were all six mill. The worst pitting and wear took the boat down to 5.7 mil so nearly new and needed nowt done. Its a 1981 and still going strong with the bloke who bought it from me.

Bargain. 

 

I often wonder whether blacking is worth the bother, or just save the money and go for an overplate when required, particularly as a lot of the corrosion is said to occur from the inside. 

[mrsmelly]

1 minute ago, rusty69 said:

Bargain. 

 

I often wonder whether blacking is worth the bother, or just save the money and go for an overplate when required, particularly as a lot of the corrosion is said to occur from the inside. 

Its a hard one to call I still black my boats every 2ish years. I have seen knackered ten years old hulls and fab 40 year old hulls. I believe its partly due to the water the boat is moored in and partly quality of the steel not that I would know anything about different waters or different steel in all honesty.

[rusty69]

6 minutes ago, mrsmelly said:

Its a hard one to call I still black my boats every 2ish years

Same here, but I guess ours will need welding at some point,as its getting on to 40 years old (survey next year,so fingers crossed)

[Machpoint005]

1 hour ago, mrsmelly said:

>>  I believe it's partly due to the water the boat is moored in, and partly quality of the steel.

I'd tend to agree. Our 22+ year old Colecraft was probably built with half-decent (British Steel) materials to start with, but our home water doesn't seem to be corrosive. 

[Tom766]

Ahh, thats where all the money goes

[WotEver]

10 hours ago, Murflynn said:

has no-one told you that freshwater mussels EAT mild steel unless it's been blacked.  

Drat, I missed that lesson. 

[WotEver]

8 hours ago, mrsmelly said:

I have seen knackered ten years old hulls and fab 40 year old hulls.

When the surveyor checked out WotEver (which was marina based on shoreline 24/7 without a GI or IT along with most of the other boats there) he noted minimal pitting anywhere - I think 0.3mm was the deepest - but told me of a 4 year old boat that he'd condemned the previous week. 

Alan had his hull dissolve away over a 12 month period  

I honestly don't know what the answer is. 

[james46]

Hi my boats been overplated i noticed when redoing the ply floor in my boat that the original base plate is rusty on the inside is it worth using inhibitor and painting over or not worth bothering thanks in advance 

[magnetman]

No. 

[Machpoint005]

^^^ what he said.

 

 

[Ewan123]

40 minutes ago, magnetman said:

No. 

 

10 minutes ago, Machpoint005 said:

^^^ what he said.

 

 

 

Could you expand on why it's not worth it?

[Tracy D'arth]

9 hours ago, james46 said:

Hi my boats been overplated i noticed when redoing the ply floor in my boat that the original base plate is rusty on the inside is it worth using inhibitor and painting over or not worth bothering thanks in advance 

No  full stop on the keys?

[james46]

Hi how do you mean on the keys 

[Lily Rose]

possibly a reference to a complete lack of punctuation sometimes making it hard to make sense of what has been written maybe not in your case or maybe it does who knows not me maybe tracy will reply in due course see no full stops

Edited September 14, 2023 by Lily Rose

[Tracy D'arth]

If posters can't write in comprehendible English with the correct punctuation, why should we bother to make useful replies?

The literacy standards on this forum are terrible.

Recent post, "my girlfriend and me" is an example: who is me?

[rusty69]

Full stops are so last century, it's clear where the sentence ends

[Lily Rose]

Methinks commas are as well its perfectly clear without them

[Captain Pegg]

You may wish to pay attention to any areas where there is - or has been - active corrosion. Typically these will be areas subject to internal water leakage.

 

I removed a huge amount of flaky rust from the rear of my cabin bilge when I overhauled the sump and pump system that I have to use due to the low freeboard of my boat.

 

In that case I applied Owatrol to try and squeeze out any remaining trapped water and then applied bilge paint.

 

But be in no doubt that it’s a partially effective treatment at best. On a boat with intermittently welded inverted channel section stiffeners and a keelson you simply can’t treat a lot of the potential moisture traps.

Don’t worry unduly about exposed dry steel that looks like it’s already sat happily with a rusted surface for years.

 

But do remember that the original baseplate still remains an important part of the structure of the boat.