Rusted bottom plate help & GRP top advice required

[Waistcoat]

Hi all,

 

Now first of all, I realise I need my hands slapped for buying without a survey, but I only did so after seeing the paperwork for the overplating and my severe lacking of funds at the time. (Also, everytime I tried to buy a boat and arrange a survey, someone would keep buying it as is and I missed out)

 

She's a 1978 - 27ft narrowboat of steel hull construction with a GRP top (2 section design). LT1 engine (single cylinder).

 

I've basically stripped the whole interior out and removed the floor to find the hull floor (baseplate) extremely damp and rusted to bits. After scraping all the flaked off rust i came across glints of silver.

I'm organising a survey once she's craned out, but wonder if this is the overplating and the original has corroded away completely?

As I have her stripped back, what's likely the best course of action in terms of the baseplate?

 

As for the GRP top, I've got to unbolt and remove, so that I can grind back and treat the gunwales and weld steel angles (upstands) on each side, so the GRP top can be joined with a buytl rubber sealant for expansion/contraction issues. An overlap skirt will be created over the upstand, which should prevent water entry.

Does this sound about right? Based on reading various threads, etc.

Also if I wanted to extend the GRP top over the front cockpit to have extra cabin space for some of a bed, what's the best way to do this? Can even be done?

 

I would overplate the GRP top, but I don't have 3K knocking about, let alone 7K!

Would also post photos, but all seem over 2MB.

 

Basically any constructive advice would be much appreciated, as I've already been told off by my dad and that was enough...

 

Many thanks,

Captain stupid

[Alan de Enfield]

7 hours ago, Waistcoat said:

As I have her stripped back, what's likely the best course of action in terms of the baseplate?

Cleaned, use 'rust remover / converter' and paint with Bilge paint.

 

7 hours ago, Waistcoat said:

As for the GRP top, I've got to unbolt and remove, so that I can grind back and treat the gunwales and weld steel angles (upstands) on each side, so the GRP top can be joined with a buytl rubber sealant for expansion/contraction issues. An overlap skirt will be created over the upstand, which should prevent water entry.

Perfect.

 

7 hours ago, Waistcoat said:

I'm organising a survey once she's craned out,

Its a 'catch-22' situation as you will need a 'good survey report' to get insurance on a 40 year old boat - if the survey is 'bad' then you will need to do the work and then have another survey to satisfy the insurance company. There is another possibility - insure the boat 3rd party only which is sufficient cover to allow you to get a licence, and will not require a survey.

 

7 hours ago, Waistcoat said:

Basically any constructive advice would be much appreciated

If you are basically refitting from scratch - very carefully read the Boat Safety Certificate requirements (you need a BSS certificate to get a licence). This will list pretty much everything you need to do for wiring, piping, etc etc. It won't tell you how to do it but it will tell you what the examiner needs to see when he does the examination.

Are you intending to liveaboard ? If so then there are different rules about who can legally work on the gas system (for example)

[Waistcoat]

Hi Alan,

 

Thanks for all your info. I doubt the survey would of uncovered the rust on the inside of the baseplate - if I'd of had one done when bought (least I keep telling myself that to feel better *gulp*)

21 minutes ago, Alan de Enfield said:

Cleaned, use 'rust remover / converter' and paint with Bilge paint.

I hear Vatcan is a good product, and also using a yacht primer afterwards. Should I use red oxide then Bilge paint? (Note that the floor is wet from years of condensation and a leaky roof, not as a running bilge).

 

32 minutes ago, Alan de Enfield said:

ts a 'catch-22' situation as you will need a 'good survey report' to get insurance on a 40 year old boat

It was last surveyed within 5 years, where various works including the overplating of 5-6mm steel were carried out following results.

So I have insurance for this year, but will need a new survey for the next 5 years.

 

35 minutes ago, Alan de Enfield said:

If you are basically refitting from scratch - very carefully read the Boat Safety Certificate requirements

It's got a current BSC till 2020, but will likely renew for safety's sake. Great advice on following the  requirements btw. Would it best to carry out once I've got the plumbing in, spray foamed the interior and set up the electrics before boarding up?

 

Some more questions

 

Would spray foam be ok on the baseplate to prevent future condensation issues?

Is it worth it on a GRP top, was looking at 30mm thick.

 

Would it be worth having further steel plating welded onto the overplating from the inside? (If this would even work).

 

Many thanks for all your advice, really appreciate it. ?

[Alan de Enfield]

2 minutes ago, Waistcoat said:

Would spray foam be ok on the baseplate to prevent future condensation issues?

Is it worth it on a GRP top, was looking at 30mm thick.

 

Would it be worth having further steel plating welded onto the overplating from the inside? (If this would even work).

Best not to 'foam' the base plate - if you get a water leak (either from the canal or your internal plumbing) you need to be able to get it out. Leave an inspection (pump-out) hatch in the floor near the rear if the boat cabin so you can check for any build up of water.

 

Small boats and overplating do not 'sit-well' the additional weight becomes a high percentage of the boat weight and make it sit much lower in the water - so low that water can enter thru hull fittings, engine vents etc. A few years ago a small 23 foot boat (I think) sank on the Thames because it had been overplated without consideration to the additional weight - add a couple of people and a dog and down it went.

 

http://narrowboatworld.com/4925-thames-narrowboat-sinking

[WotEver]

18 minutes ago, Waistcoat said:

Would it best to carry out once I've got the plumbing in, spray foamed the interior and set up the electrics before boarding up?

Best to not hide the electrics too much as it makes future alterations much more difficult. Certainly you can run some of the main heavy feeds behind the panelling but it’s also good to have feeds running in a trough below the gunwales for easy accessibility. 

 

Gas pipes must be surface mounted so that the entire run is accessible to the BSS examiner. If you run any water pipes behind panels ensure that there are no hidden joints, or that the panels are easily removable. 

 

I’d also run a spare pair of heavy duty cables the entire length of the boat - you never know when you might want 12V power up front for something. 

 

Wire the 230V as radials - no need for a ring, and it’s actually more difficult to achieve. 

[Waistcoat]

Wow, so much information. Absolute legend!

I'll try and put some photos up once I can shrink there size.

 

Hopefully getting her craned out this weekend and hardstanding

38 minutes ago, Alan de Enfield said:

Best not to 'foam' the base plate - if you get a water leak (either from the canal or your internal plumbing) you need to be able to get it out. Leave an inspection (pump-out) hatch in the floor near the rear if the boat cabin so you can check for any build up of water.

 

Small boats and overplating do not 'sit-well' the additional weight becomes a high percentage of the boat weight and make it sit much lower in the water - so low that water can enter thru hull fittings, engine vents etc. A few years ago a small 23 foot boat (I think) sank on the Thames because it had been overplated without consideration to the additional weight - add a couple of people and a dog and down it went.

 

http://narrowboatworld.com/4925-thames-narrowboat-sinking

Yes, I did worry about the foam on the floor and possible leaks, good advice.

Some works occured after the previous survey, which included raising some of the entry/exit holes along the side.

 

I've also removed a fair bit of heavy interior and replacing with a bit more lightweight.

[Boater Sam]

Did the overplating include a new baseplate? Often I have found that refooting is described as an overplate job and the baseplate is not done. Scaling rust often looks worse than it is, 10mm of scale equates to 1mm of steel lost roughly. I would doubt you have scraped off 10mm.

[Sea Dog]

9 hours ago, Waistcoat said:

 

I've basically stripped the whole interior out and removed the floor to find the hull floor (baseplate) extremely damp and rusted to bits. After scraping all the flaked off rust i came across glints of silver.

I'm organising a survey once she's craned out, but wonder if this is the overplating and the original has corroded away completely?

As I have her stripped back, what's likely the best course of action in terms of the baseplate?

Overplating is more frequently required on the side than the usually thicker and less exposed baseplate.  Do you know it was the baseplate that was overplated or have you assumed?  Many folk here have found a rusty mess under their floors and survived - steel produces rust at many times the thickness of the metal converted, so it looks a lot worse than it often is.  Your forthcoming survey will give you the answer, but I offer this as a glimmer of hope in the meantime.

 

[Mad Harold]

I too bought my boat without a survey,for the same reason as you.[Missing out because there was someone else willing to buy without a survey]

The nearest dry dock was not available for seven weeks so I took the risk and bought.When I had it surveyed,it was found to be satisfactory for comprehensive insurance cover.[Not a brilliant survey report,but generally ok]

My only regret is not being a member of CNF before buying,because I would have been much better informed about the ins and outs of buying a boat thanks to the vast amount of information generously contributed by members.

Please keep us informed of your progress,it could be useful to others in er the same boat.   Best of luck.

[Waistcoat]

1 hour ago, Sea Dog said:

Do you know it was the baseplate that was overplated or have you assumed?

The guy that sold it to me said he saw the plating all made up and the boat was simply lowered in and welded on. Other than that I don't know. So yes assuming. The new shiny steel I saw become visible as most of the rust has been scraped away seemed to look flat and brand new.

 

The odd thing was it looked like this new looking steel was attached to the boat ribs/cross sections (or whatever they are called) running across sections of the floor of the boat. I need to fully clear out near these ribs this weekend to confirm that.

 

If that's the case, does that mean the baseplate may have been redone? Just wondered why the residual rusted steel would still be there? I'm new to all this though.

 

Note - Was about 10 to 12mm thick rust taken off the floor.

 

Thanks for the Glimmer and the advice, really appreciate it! ?

[Waistcoat]

2 hours ago, WotEver said:

Best to not hide the electrics too much as it makes future alterations much more difficult.

Thanks for this 'Wotever' and the other info given.

 

Also, I best look that up Furness. I'm keeping a photo record, sequence of works and a detailed price list. That way I can help someone else who gets in the same predicament. Also, if I ever sell it in the future, I can show the potential purchaser that everything has been done properly and they won't get messed about.

41 minutes ago, Furness said:

My only regret is not being a member of CNF before buying,because I would have been much better informed about the ins and outs of buying a boat

[Tacet]

10 hours ago, Waistcoat said:

 

 

As for the GRP top, I've got to unbolt and remove, so that I can grind back and treat the gunwales and weld steel angles (upstands) on each side, so the GRP top can be joined with a buytl rubber sealant for expansion/contraction issues. An overlap skirt will be created over the upstand, which should prevent water entry.

 

 

A question really. If you are lifting the cabin off, can the angle/upstand be welded on such that it is inside the cabin even if behind the linings?  It would weather better.

 

   

 

[Waistcoat]

As the boat is a cruiser and so the cabin is not huge, I was looking to extend the roof area above the front cockpit like a permanent cratch cover with a little opening window at the front.

 

This would likely need to be GRP also, I'm trying to work out the best way to do this, perhaps having to buy a moulded section and then join and seal to the original roof end. Unless anyone has any ideas or think it's going to be a total failure?

 

This was so I could mount a bed end within the front cockpit (I will have to work out how best to still be able to refill the water tank, as the access point is there). Then the bed would overhang and be mounted on a frame, with underneath storage available.

[Boater Sam]

It would be a rare and mammoth job to remove the original baseplate and weld a new one to all the transverse stiffening angles, very unlikely as the boat would have to totally stripped to do it.

So your bottom plate sounds to be not so bad if it is not pitted too badly underneath, it may have lost not much more than its mill scale inside.

[Waistcoat]

12 minutes ago, Tacet said:

If you are lifting the cabin off, can the angle/upstand be welded on such that it is inside the cabin even if behind the linings? 

That was the plan, unless someone has a opinion to prove otherwise, I'm always open to beneficial suggestions. ?

2 minutes ago, Boater Sam said:

it may have lost not much more than its mill scale inside.

I bloomin hope so. 

[Waistcoat]

Yet another question (sorry!).

If you can visualise the idea...

 

I was looking to build a galley which would have a circle in the centre walkway, due to the curved units on both sides.

A slightly pitched tiled floor area with a grill and soak away/sump in the middle.

 

Then a shower head above the walkway circle with a spiral feed pipe with which to hang a curtain rail on, allowing me to pull totally around when in use. (All very fancy pants, and meant to save on space as cabin is small). I'm just worried about the condensation! Is there a possible extractor fan type option I could place directly overhead to counteract this?

 

This is going to all cost, but it's ok if I do bits every month.

[Mike Hurley]

12 volt extractor fans are common on Motor homes and caravans so probably loads on ebay.

[ditchcrawler]

4 hours ago, Waistcoat said:

Yet another question (sorry!).

If you can visualise the idea...

 

I was looking to build a galley which would have a circle in the centre walkway, due to the curved units on both sides.

A slightly pitched tiled floor area with a grill and soak away/sump in the middle.

 

Then a shower head above the walkway circle with a spiral feed pipe with which to hang a curtain rail on, allowing me to pull totally around when in use. (All very fancy pants, and meant to save on space as cabin is small). I'm just worried about the condensation! Is there a possible extractor fan type option I could place directly overhead to counteract this?

 

This is going to all cost, but it's ok if I do bits every month.

Sounds an interesting idea, just dont try frying the bacon at the same time, the fat spits

[Waistcoat]

46 minutes ago, ditchcrawler said:

Sounds an interesting idea, just dont try frying the bacon at the same time, the fat spits

I was more thinking of washing up and then rinishing the dishes off while I'm in there! ?