Bottom Blacking

[Daftmare]

We are having the blacking done on the boat in June (before repaint). Taking it back to Newbury as the cost is half of what Pyrford charge on the R. Wey.

 

I really thought that they blacked the BOTTOM of the boat. Turns out they don't? Just the sides below the water line.

 

Just shows how little I know............

 

Jo.

[Nickhlx]

We are having the blacking done on the boat in June (before repaint). Taking it back to Newbury as the cost is half of what Pyrford charge on the R. Wey.

 

I really thought that they blacked the BOTTOM of the boat. Turns out they don't? Just the sides below the water line.

 

Just shows how little I know............

 

Jo.

 

If its only the sides that (most) have done..... - I think the issue is that the bottom gets "scraped" naturally pretty quickly and there is little point in also blacking that as well, although I am sure many do..... - then would it be an option to D-I-Y it yourself for just the craneage cost ? A possible additional benefit might be that it does get fully dry / cured between coats and the full number of coats specified / quoted for does get done. A messy job though from what I have heard, but protective clothing isn't too prohibitive - how about a blacking party ?

 

Nick

[WJM]

It is also to do with the oxygen content of the water two feet down. It is only the highly oxygenated water near the surface that poses a threat to the metal. If you look at an old sunken steel boat you will see that everything above and just under the surface rusts but deeper down the steel is actually preserved by its immersion. Sinking steel boats is a method of preserving them.

[Guest]

I have to admit (even though thinking about it it is logical) I'd never appreciated blacking didn't include the actual hull bottom - makes the prospect of going DIY more appealing....less to paint...

[JonL]

"Sinking steel boats is a method of preserving them"

 

An interesting concept - might be OK for the steel but kind of ruins everything else !

[Victor Vectis]

"Sinking steel boats is a method of preserving them"

 

Well it worked for the Titanic........................sort of

[Daftmare]

If its only the sides that (most) have done..... - I think the issue is that the bottom gets "scraped" naturally pretty quickly and there is little point in also blacking that as well, although I am sure many do..... - then would it be an option to D-I-Y it yourself for just the craneage cost ? A possible additional benefit might be that it does get fully dry / cured between coats and the full number of coats specified / quoted for does get done. A messy job though from what I have heard, but protective clothing isn't too prohibitive - how about a blacking party ?

 

Nick

 

 

Hi Nick, we have thought of doing it ourselves, for all of 10 seconds....

 

We are bringing her back to Newbury during Whitsun week, so perhaps we can meet up - a party perhaps, but not a blacking party!

 

Jo

[Nickhlx]

Hi Nick, we have thought of doing it ourselves, for all of 10 seconds....

 

We are bringing her back to Newbury during Whitsun week, so perhaps we can meet up - a party perhaps, but not a blacking party!

 

Jo

 

 

Sounds like you have greater experience than me on blacking, or have seen it being done ( which I will watch before I decide !)

 

Certainly up for a meet up sometime around then / accompany you for a stretch / even crew (steer) for a bit if you both can't really "afford" the time off ?

( not quite up to doing the locking though yet)

 

Nick

[Chertsey]

Interestingly, when Andante was blacked in Newbury (at All Aboard Marine IIRC) in 2005, they did do the bottom, although I subsequently realised that this is unusual.

[Tim Lewis]

Hi Nick, we have thought of doing it ourselves, for all of 10 seconds....

 

We are bringing her back to Newbury during Whitsun week, so perhaps we can meet up - a party perhaps, but not a blacking party!

 

Jo

 

Not quite sure what you are afraid of, if you are only painting from the waterline sides only two people can put on a coat in a couple of hours. As others have said its waiting for it to dry that makes it a long job.

 

Of course good prepataion is essential but a good pressure wash and wire bushing any scale shouldn't take more tha half a day.

 

Tim

[blackrose]

Takes me a full day to pressure wash and another full day to wire brush my boat but I'm doing it on my own. Two days of prep and a coat of blacking each day for 3 days plus another one around the waterline. 24 - 48 hours to dry before it goes back in the water and that's it, I'm knackered!

 

I did think about doing the baseplate until I got under my 12' widebeam and had a look. No thanks! It looks the size of a tennis court from underneath. The rust I was worried about on the baseplate turned out to be light surface gingering which just brushed off with my hand. However, don't forget to black the counter (uxter) plate and the baseplate at the bow if it's the kind that curves upwards toward the waterline.

Edited May 7, 2011 by blackrose

[nb Innisfree]

Takes me a full day to pressure wash and another full day to wire brush my boat but I'm doing it on my own. Two days of prep and a coat of blacking each day for 3 days plus another one around the waterline. 24 - 48 hours to dry before it goes back in the water and that's it, I'm knackered!

 

I did think about doing the baseplate until I got under my 12' widebeam and had a look. No thanks! It looks the size of a tennis court from underneath. The rust I was worried about on the baseplate turned out to be light surface gingering which just brushed off with my hand. However, don't forget to black the counter (uxter) plate and the baseplate at the bow if it's the kind that curves upwards toward the waterline.

 

Considering it's near the waterline and daylight I'm always surprised how good the blacking is on the uxter plate, better than anywhere else.

[Daftmare]

Not quite sure what you are afraid of, if you are only painting from the waterline sides only two people can put on a coat in a couple of hours. As others have said its waiting for it to dry that makes it a long job.

 

Of course good prepataion is essential but a good pressure wash and wire bushing any scale shouldn't take more tha half a day.

 

Tim

 

 

Hi Tim

Not afraid at all, in fact if I got organised I am sure it would be fun - its just time management really. Happy to leave it to the experts. Sounds like the bottom may get blacked after all, at All-Aboard!

 

Jo.

[Dominic M]

We are having the blacking done on the boat in June (before repaint). Taking it back to Newbury as the cost is half of what Pyrford charge on the R. Wey.

 

I really thought that they blacked the BOTTOM of the boat. Turns out they don't? Just the sides below the water line.

 

Just shows how little I know............

 

Jo.

Hi Jo,

 

In an ideal world you should black the bottom plate. I know all the arguments about it being scraped off on the canal bed, but the few boats I have seen where this has been done have bottom plates in significantly better condition 10 years down the line. The reason most boats are not blacked on the bottom is historical bad practice and because it is impossible to do in many dry docks. Putting it on hard standing is the answer, and then having an interim lift so that you can get to the two bits that were sitting on the bostocks. It will cost you more, but how much do you value your boat?

 

It is not just about oxidising. Blacking the bottom plate will reduce galvanic corrosion.

[Daftmare]

Hi Jo,

 

In an ideal world you should black the bottom plate. I know all the arguments about it being scraped off on the canal bed, but the few boats I have seen where this has been done have bottom plates in significantly better condition 10 years down the line. The reason most boats are not blacked on the bottom is historical bad practice and because it is impossible to do in many dry docks. Putting it on hard standing is the answer, and then having an interim lift so that you can get to the two bits that were sitting on the bostocks. It will cost you more, but how much do you value your boat?

 

It is not just about oxidising. Blacking the bottom plate will reduce galvanic corrosion.

 

Thanks Dominic

I will check with Paul Hutley to see what he usually does, and go from there...

 

Jo.

[Tony Brooks]

 

It is not just about oxidising. Blacking the bottom plate will reduce galvanic corrosion.

 

 

 

Or possibly concentrates it on any parts where the blacking is missing.

[Steilsteven]

Returned to our mooring yesterday following a diy docking at Newbury with PETRA.

No, we didn't paint the bottom plates just as we didn't last time, three years ago.

PETRA has curved chines and these get painted to just beyond where they meet the bottom plate, the stern swims get painted to the same extent as do the bows. Upon inspecting the bottom plates, they appear to be as smooth as they were six years ago when she was in for her pre purchase survey in Holland and there was no evidence of electrolitic reaction anywhere on the hull ( she is fitted with a galvanic isolator ) even though she has been connected to shore power for most of that time. I believe that the bottom plates are at least eight years old, so I'm convinced that painting them would be wasted effort and expence. Having said that, if she was to spend most of her time in salt or brackish water I would.

 

As an aside for those who choose to diy, the Mrs has discovered the best method for removing bitumous paint from your skin, Johnson's baby oil!

It instantly dissolves the stuff and then just wipes off.

 

Keith

Edited May 10, 2011 by Steilsteven

[Grace and Favour]

snippity>>

 

As an aside for those who choose to diy, the Mrs has discovered the best method for removing bitumous paint from your skin, Johnson's baby oil!

It instantly dissolves the stuff and then just wipes off.

 

Keith

 

Have you thought about starting a 'Beauty tips' thread with this (excellent) piece of advice

[RLWP]

Not quite sure what you are afraid of, if you are only painting from the waterline sides only two people can put on a coat in a couple of hours. As others have said its waiting for it to dry that makes it a long job.

 

<snip>

 

Tim

 

Of course, while you are waiting, you can sort out and repaint your tunnel bands

 

Richard

[Dominic M]

Returned to our mooring yesterday following a diy docking at Newbury with PETRA.

No, we didn't paint the bottom plates just as we didn't last time, three years ago.

PETRA has curved chines and these get painted to just beyond where they meet the bottom plate, the stern swims get painted to the same extent as do the bows. Upon inspecting the bottom plates, they appear to be as smooth as they were six years ago when she was in for her pre purchase survey in Holland and there was no evidence of electrolitic reaction anywhere on the hull ( she is fitted with a galvanic isolator ) even though she has been connected to shore power for most of that time. I believe that the bottom plates are at least eight years old, so I'm convinced that painting them would be wasted effort and expence. Having said that, if she was to spend most of her time in salt or brackish water I would.

 

As an aside for those who choose to diy, the Mrs has discovered the best method for removing bitumous paint from your skin, Johnson's baby oil!

It instantly dissolves the stuff and then just wipes off.

 

Keith

Three years ago I was involved in the prospective sale of a 10 year old boat. The sale collapsed when taking it out of the water revealed extensive galvanic corrosion. The boat had no 240v system, and never had had. So it must have come from a third party external source. So, if the bottom plate had been protected, the damage would have been greatly limited if not prevented. Just because your boat has a GI doesn't therefore mean that it is immune from galvanic corrosion.

 

At the end of the day, it's up to the individual boat owner as to whether they black the bottom plate or not. However, a number of surveyors recommend this, and from what I've seen, it is a benefit to do so. It certainly won't harm the boat. I believe the Royal Navy treat the bottom of all their craft, so maybe they know something too. Whether salt water or fresh, the argument about a bottom plate being away from the area where an air and water mix causes corrosion still holds true, so whether brine or not is irrelevant.

Edited May 10, 2011 by Dominic M

[Nickhlx]

Three years ago I was involved in the prospective sale of a 10 year old boat. The sale collapsed when taking it out of the water revealed extensive galvanic corrosion. The boat had no 240v system, and never had had. So it must of come from a third party external source. So, if the bottom plate had been protected, the damage would have been greatly limited if not prevented. Just because your boat has a GI doesn't therefore mean that it is immune from galvanic corrosion.

 

At the end of the day, it's up to the individual boat owner as to whether they black the bottom plate or not. However, a number of surveyors recommend this, and from what I've seen, it is a benefit to do so. It certainly won't harm the boat. I believe the Royal Navy treat the bottom of all their craft, so maybe they know something too. Whether salt water or fresh, the argument about a bottom plate being away from the area where an air and water mix causes corrosion still holds true, so whether brine or not is irrelevant.

 

 

I also heard a story about a boat that had no shoreline power but was apparently between two boats that did - one ( or both ?) had a serious problem and was deemed to have caused the corrosion that this boat, stuck in the middle, had suffered, even though it was not electrically connected to those on each side of it ..

 

Nick