Is blacking just bituminous paint

[truckcab79]

As per title really. I need blacking for the space under the floors. Any reason not to use a quality bituminous paint such as Bostik. Is something like Teac just subject to the ‘boat tax’ at about twice the price?  When I search for hull blacking most of the results are for generic bituminous paints with hull blacking as just one of their uses.  Can’t see anything on spec sheets that would suggest otherwise.  

[blackrose]

Since blacking marketed for boats only lasts 2 or 3 years before it needs redoing I really can't imagine that bituminous paint not branded as boat blacking could possibly not last as long (or be any worse).

 

I'm pretty sure a hundred years ago there was no such thing as boat blacking and it was all just bitumen. These days of course some manufacturers have focused in on the boat market where they can charge a premium for what's likely to be the same stuff. I know some of them claim their products have enhanced diesel resistance, etc, but it's starting from a fairly low base and in my experience it doesn't do what it says on the tin.

 

I used to spend a lot of time and effort prepping the hull and put on 2 coats of Rylards Rytex followed by 2 coats of Rylards premium but it still only lasted 3 years, so I wouldn't worry too much about it because whatever bitumen based product you apply you'll be back out the water in a few years anyway.

 

The only time is really worth putting a lot of time and effort into prepping & painting the undersides is if you're using a better paint system like epoxy. Then it really pays to do it properly following the technical data sheet to the letter. But if you're using bitumen just slap it on and don't worry about it.

Edited November 13, 2023 by blackrose

[TandC]

You're talking about your cabin bilges - which with luck, you don't want to see again...   I used SML Paint's "Bilge paint" - it applied very easily with roller and brush for the nooks and crannies.  It dries very quickly allowing you to get a good couple of coats on and dry.   PLenty of ventilation and a mask.

 

It was a lot easier to apply than blackjack/bitumen (ive done it twice previously using bitumen on different boats), leaves a much better finish, doesn't stink of tar for weeks and arguably is a modern solution.  Can't remember the cost but it wasn't a lot to get coverage for two coats. 

 

 

[truckcab79]

18 minutes ago, TandC said:

You're talking about your cabin bilges - which with luck, you don't want to see again...   I used SML Paint's "Bilge paint" - it applied very easily with roller and brush for the nooks and crannies.  It dries very quickly allowing you to get a good couple of coats on and dry.   PLenty of ventilation and a mask.

 

It was a lot easier to apply than blackjack/bitumen (ive done it twice previously using bitumen on different boats), leaves a much better finish, doesn't stink of tar for weeks and arguably is a modern solution.  Can't remember the cost but it wasn't a lot to get coverage for two coats. 

 

 

It’s under the whole cabin floor and It’s already been blacked, probably when built so I believe has to be used again rather than painted.  I will need to do the bilge and gas locker but same there also.  

Funnily enough just Googled again and The Nareowboat that James built came up and he’s using the Bostik stuff. Think I’ll go with that.  Original blacking seems to have lasted over 40 years so it’ll probably do a few more. Will all be getting wire brushed and vactan’d first though there very little sign of rust. Cross supports look a bit scaly but nothing that a knotted wheel won’t get rid of.  

Edited November 13, 2023 by truckcab79

[TandC]

Ah in which case yes, crack on and slap it on!   I used Toolstation "BlackJack" last time - held up to the general moisture of condensation etc fine.   It's a bastard to get off with a wire brush tho as it gets hot and melts.

 

 

[truckcab79]

11 minutes ago, TandC said:

Ah in which case yes, crack on and slap it on!   I used Toolstation "BlackJack" last time - held up to the general moisture of condensation etc fine.   It's a bastard to get off with a wire brush tho as it gets hot and melts.

 

 

 Cheers. Already purchased. Less than £30 a 5 ltr tin can’t really go wrong. It’s only topping up what’s there which miraculously after all this time seems pretty much all intact. 
 

The ballast mostly seems to sit on a thin layer of felt and then blacking. Bearing in mind the bow drains under the length of the floor to the bilge at the rear you’d think the layers and the fact it must never fully dry out would be a recipe for severe rust but seems in very good condition thus far. 🤞

[Arthur Marshall]

The bow of mine drained via a pipe to the engine bilge rather than down the length of the cabin bilge. Are you sure yours doesn't? The cabin bilge never got wet.

The boat sank, though, when it rained so much while I had flu and couldn't get to the boat the rear bilge filled up and down it went. The auto bilge pump failed like they always do. I welded up the drain hole at the front and raised the deck above the waterline.

[TandC]

If you're able to - removing the felt entirely, repainting, and then putting the slabs down onto something to raise them off the baseplate would be a better solution to allow some airflow under to help the bilges dry.  Old hosepipe, thick tile spacers, scrap UPVC etc are all good.    Having a wet through bilge like that is pretty uncommon now. 

[truckcab79]

1 hour ago, TandC said:

If you're able to - removing the felt entirely, repainting, and then putting the slabs down onto something to raise them off the baseplate would be a better solution to allow some airflow under to help the bilges dry.  Old hosepipe, thick tile spacers, scrap UPVC etc are all good.    Having a wet through bilge like that is pretty uncommon now. 

Yep. That’s the plan.  I’m taking all the felt out. The ballast is classic old school broken slabs so rough enough to not have many places of contact against the floor steel.  It’ll be going back on 5mm tile spacers as I have loads of them 

 

I thought I’d read that Springers had a central tube through which the water ran front to back and I’m sure the design changed over time but mine is just all open.  

 

Many thanks. 

18 hours ago, Arthur Marshall said:

The bow of mine drained via a pipe to the engine bilge rather than down the length of the cabin bilge. Are you sure yours doesn't? The cabin bilge never got wet.

The boat sank, though, when it rained so much while I had flu and couldn't get to the boat the rear bilge filled up and down it went. The auto bilge pump failed like they always do. I welded up the drain hole at the front and raised the deck above the waterline.

Cheers.  No. Mine is definitely open. Have a look in my pictures in the build blog section. Don’t be fooled by the central ‘box section’ in the pics. It’s open C channel.  Unless it changes as we take the floor up but can’t see why it would.  
 

Good point on the pump.  I test mine every time we go to the boat. Normally weekly but a second one probably wouldn’t go amiss. 

Edited November 15, 2023 by truckcab79

[magnetman]

If the bilge is liable to get wet it seems to me that paint would be a bad idea as it will form moisture traps unless the coating is 100% perfect. 

 

I'd scrape and vacuum all the loose rust orf and ensure good air flow then leave it unpainted. 

 

If you can get it perfectly clean then maybe worth painting. Good luck. 

 

 

 

If the bilge is liable to get wet it seems to me that paint would be a bad idea as it will form moisture traps unless the coating is 100% perfect. 

 

I'd scrape and vacuum all the loose rust orf and ensure good air flow then leave it unpainted. 

 

If you can get it perfectly clean then maybe worth painting. Good luck. 

 

 

 

 

 

ETA do it twicewice !

[truckcab79]

18 minutes ago, magnetman said:

If the bilge is liable to get wet it seems to me that paint would be a bad idea as it will form moisture traps unless the coating is 100% perfect. 

 

I'd scrape and vacuum all the loose rust orf and ensure good air flow then leave it unpainted. 

 

If you can get it perfectly clean then maybe worth painting. Good luck. 

 

 

 

If the bilge is liable to get wet it seems to me that paint would be a bad idea as it will form moisture traps unless the coating is 100% perfect. 

 

I'd scrape and vacuum all the loose rust orf and ensure good air flow then leave it unpainted. 

 

If you can get it perfectly clean then maybe worth painting. Good luck. 

 

 

 

 

 

ETA do it twicewice !

It’s definitely not being painted.  It’s already been painted with red oxide and then bitumen in the past. Probably just once when it was new I suspect. So long as I can get it dry enough in this weather it’ll be getting another coat of bitumen. 
 

And it’s not ‘liable’ to get wet.   It will definitely get wet 😂 as it’s the only way out for rainwater that enters the bow, to exit. Seems to have worked well enough for 40 odd years thankfully.  👍

Edited November 15, 2023 by truckcab79

[magnetman]

I'd block up the drains and make a sump for a pump in the well deck. 

[truckcab79]

Just now, magnetman said:

I'd block up the drains and make a sump for a pump in the well deck. 

Will have a look at that. Bow is pretty tiny though.  Not sure I’ll find space.  Not lifted boards there yet mind. Could well be loads of space under for all

I know. Good idea. 👍

[beerbeerbeerbeerbeer]

1 minute ago, truckcab79 said:

It’s definitely not being painted.  It’s already been painted with red oxide and then bitumen in the past. Probably just once when it was new I suspect. So long as I can get it dry enough in this weather it’ll be getting another coat of bitumen

Sounds to me like you’ve the same under your floor as I have/had under mine. And my bilges drain as yours do.

On top of my iron/steel ballast I had chicken wire with rock wool laid on top. It had become a right mess over the decades,

 

Where able, I have removed everything. 
I had some over plating done and permanently removed ballast where I could,

there seemed to be a layer of primer in good shape so I’ve left it at that,

There is an area under the water tank in the bow that I reblacked. 

Where I could I cleared the lumber holes and water will run to the stern,

There are now large inspection boards I can lift up in the back of the cabin,

and I’ve left plenty of gaps for air to flow,

 

as you say, it’s surprising how under all the mess the steel is in good shape,
 

 

 

[TandC]

Cratch cover??

 

It must make it a bit miserable inside if you've always got a load of moisture coming in from the bow and running under your feet ... 

 

 

[truckcab79]

40 minutes ago, TandC said:

Cratch cover??

 

It must make it a bit miserable inside if you've always got a load of moisture coming in from the bow and running under your feet ... 

 

 

Yep. It’ll be getting covered.  Tonneau probably rather than cratch. Same for the rear.  

[truckcab79]

3 hours ago, TandC said:

Cratch cover??

 

It must make it a bit miserable inside if you've always got a load of moisture coming in from the bow and running under your feet ... 

 

 

As far as miserable is concerned the boat is old, but new to us.  As far as I can tell timber floor etc is original.  Some localised rot where water was getting in through a hole in the front bulkhead and not surprisingly around the shower area but other than that and having started cutting it out I can confirm it’s all amazingly solid so I don’t think it’s ever caused any issues.  
 

I’ll be putting timber floors down and using a heavy DPM so in effect the moisture is sealed into the space below the floor and can’t really cause any issue.   

Edited November 15, 2023 by truckcab79

[magnetman]

Also Springers have a reputation for being made of gasometer steel.

 

I'm not all that sure why gasometer steel would be better than other types of steel but it is an enduring legend and of course there was quite a signifcant problem in the steel market in the late 70s. Everyone knows that R, S and T reg cars collapsed fairly quickly. The rust got in there.

 

It could have been a mafia thing. One must not be too overt with accusing the mafia because they know where one lives.

 

Boats, while having thicker steel in general, can escape the obvious 'I can put my hand through that hole in the wing there' issue associated with cars but it is definitely Cool if boats were made from gasometer steel.

 

The metallurgists will be all over this but I bet gasometer steel is far better than normal "we bought it from some Italian guy with a yankie accent in 1976" type steel.

 

Its all in the microstructure. They do it deliberately.

 

I think Sam Springer knew what he was doing.

 

[truckcab79]

Certainly seems to with ours.  Very impressed with how well it’s fared.  

[harrybsmith]

Many people make a bilge paint, Withams being my preferred one, seems really good quality and is immersion rated

 

[truckcab79]

1 hour ago, harrybsmith said:

Many people make a bilge paint, Withams being my preferred one, seems really good quality and is immersion rated

 

But none for application over bitumen as in my case as far as I’ve found.