Jump to content

Best rust treatment for Hull floor


Rainyday

Featured Posts

Hi, looking for advice please! First boat. I've managed to lift the soggy half of the floor and the unbelievably heavy waste tank. Before putting down marine ply (as the ballast are damp so I want to put good stuff over) I should probably treat the rusty floor. 

The hull had a good survey last year albeit just tested from the exterior. How do I stop rust in its tracks? Best and simplest way please! 

 

Which is the brand that you spray/paint over and it hardens the rust without you needing to remove it first? 

If you could give me a stepped process and links to a UK store would be unbelievably helpful. Trying to do this outside the hours of my day job! And would like to move in next month ?

 

Thanks! 

 

PS. I heard fertan was good but downside you have to wash away with water. 

Pps. Prefer non-toxic option if possible 

IMG_20190113_175247.jpg

IMG_20190113_175303.jpg

Link to comment
Share on other sites

Are you going to be able to access the entire baseplate? If not, i would just clean up the area you can see and perhaps just coat with bitumen. Having one area of well maintained baseplate won't make a lot of difference. 

Link to comment
Share on other sites

First it needs to dry out,  then you have to attack it with a grinder /wire wheel or similar...then let it dry again as there will be moisture behind the rust.

Then use Vactan or Owatrol oil  if that is the way you want to go, this time of year leave at least 48  hours or more before overcoat ing  with several layers of bilge paint.

Link to comment
Share on other sites

11 minutes ago, BWM said:

Are you going to be able to access the entire baseplate? If not, i would just clean up the area you can see and perhaps just coat with bitumen. Having one area of well maintained baseplate won't make a lot of difference. 

I will check under other parts of the floor and make some holes for ventilation (is that a good idea or fuels rust!?) but this is the part where floors were damp, from bathroom and back to heating system. The rest is dry and hopefully doesn't need this attention. 

Boat built in 1994 by a good builder but there was a lot of condensation and past leaks without much maintenance. 

Link to comment
Share on other sites

22 minutes ago, Narrow newbie said:

I will check under other parts of the floor and make some holes for ventilation (is that a good idea or fuels rust!?) but this is the part where floors were damp, from bathroom and back to heating system. The rest is dry and hopefully doesn't need this attention. 

Boat built in 1994 by a good builder but there was a lot of condensation and past leaks without much maintenance. 

If the rust is only in that area then it would definitely be worth taking care of. Clean back with a scraper and then with an angle grinder/knotted cup brush, allow to dry and then apply rust converter. My preference would be coovar but it isn't cheap, use as the directions and the overcoat with bilge paint within the specified time-that is most important as you don't rub down between coats and rely on chemical bonding. 

Link to comment
Share on other sites

I don't know the other brands mentioned but Kurust gets my vote for definable patches - for me bitumen is only reliable if you can get a clean dust free prepared floor surface a bit like you can achieve externally on the hull - therefore usually not worth the effort internally as it wont adhere 100% and then traps water which defeats the object.

Edited by Halsey
Link to comment
Share on other sites

Looks like you're in the 'getting worse before it gets better' stage. Hats off for tackling it. Angle grinder / wire wheel thingy would probably make a mess in the rest of the boat but I think I would lift the ballast, allow it to dry a bit, clean up the steel as well as you can, probably with a scraper to remove what looks like scale in the pics then Vactan. Not sure if you need to paint on top. If you could lift the ballast blocks a bit so they aren't on the steel that would be good but you haven't got much height to play with, even putting a washer or thin nut under each corner of each block might help. When you relay the floor I wouldn't use marine ply, just exterior ply will be fine. Most water collects right at the back of the boat and that could be worth a look at if you can face it. Any ventilation that you can get under there will be good. Dry steel will not rust so anything you can do to help that will be good.

Link to comment
Share on other sites

5 hours ago, Bee said:

Not sure if you need to paint on top. If you could lift the ballast blocks a bit so they aren't on the steel that would be good but you haven't got much height to play with, even putting a washer or thin nut under each corner of each block might help.

Short cut lengths of mains cable work well. They don’t rust and they’re ‘rubbery’. 

Link to comment
Share on other sites

1 hour ago, WotEver said:

Short cut lengths of mains cable work well. They don’t rust and they’re ‘rubbery’. 

I have heard of that, and the other one is those cross shaped plastic tile spacers, which lift the bricks/slabs up a couple of millimetres.

Edited by Guest
Link to comment
Share on other sites

Thanks so much for all of your excellent tips. Really helps my motivation too! I hadn't thought about lifting the ballast but after today's visit to the boat, glad the rust is drying but it's clear just how damp the blocks are so I will do as you suggest and put something rubbery underneath ? I'll also try moving them around. next thing on the shoppinglist: crowbar. The project just keeps growing. ?

IMG_20190120_145715.jpg

  • Greenie 1
Link to comment
Share on other sites

Folk worry about rust, keeps them awake at night.  Old boats often had poured concrete or loose gravel ballast, which one wet never really dries out, most are still afloat.

!0mm of heavy rust scale equates to about 1mm of lost steel, I doubt that the rust on your baseplate is more than 2 or 3 mm thick.

Sleep easy.

Vactan is good.

I use neat phosphoric acid, that's what Kurust, Jenolite and other rust converters (and Coca Cola!) contain, its cheap by the gallon.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.