Survey Complications, The 'O' word again and pitted baseplate

[Mikexx]

Happy Ending,

 

The sellers came down £7000 for the repairs, but with the repairs quoted at £10,000 it still wasn't going to be worth my while!

 

However, I called a boatyard back home who had over-plated areas on the waterline on my previous project of a boat.

 

They did a really good welding job and it was great to be in the yard with them last summer, on calling them they gave me a far more cost effective quote which meant I was able to make it all work and i'm over the moon to have the work being done by a yard that I know and trust.

 

A great conclusion.

 

Steel has a density of ~8,000 kg/m^3 so the addition of 6mm steel will add a nominal 5cm / 2" to the draft. I would assess where the port holes are whether they should be moved.

[Jak]

Very pleased to hear it's worked out for you. Happy boating!

[cutsurfer]

 

A great conclusion.

 

Steel has a density of ~8,000 kg/m^3 so the addition of 6mm steel will add a nominal 5cm / 2" to the draft. I would assess where the port holes are whether they should be moved.

Thank you, that's useful to know, I think the only close call will be the deck drains but I have a few boards that I think will be fairly easy to left up and remove ballast from :-)

[Neil2]

In practice it seems to work out quite a bit less than 2" depending on the shape of the boat at the waterline. It helps If the uxter plate isn't included (in the overplating). Obviously you wait until she's back in the water first and keep your fingers crossed. Removing ballast can be a horrible job.

[Mikexx]

In practice it seems to work out quite a bit less than 2" depending on the shape of the boat at the waterline. It helps If the uxter plate isn't included (in the overplating). Obviously you wait until she's back in the water first and keep your fingers crossed. Removing ballast can be a horrible job.

 

Obviously 48mm is less than 2" and I was assuming the whole of the bottom would be plated.

 

I have little knowledge why a boat would have ballast unless it was listing without it.

[Alan de Enfield]

 

Obviously 48mm is less than 2" and I was assuming the whole of the bottom would be plated.

 

I have little knowledge why a boat would have ballast unless it was listing without it.

 

A boat has 'ballast' to increase the 'under-water'; weight.

Without it the top (above water line) is heavier than that below the water line and it turns 'turtle' (up side down)

 

If you add (say) 2 tons of extra metal, then you can in theory remove 2 tons of ballast.

My last NB had a 13mm thick base plate and because of the 'extra weight' it required very little in the way of ballast, so, the floor was lower and the head room greater.

 

Even 'huge' super tankers have to travel, either full of cargo - or - 'in ballast' where they pump millions of litres of sea water into the tanks to simulate being 'loaded' and to ensure the 'bottom' is heavier than the 'top'

[Mikexx]

 

A boat has 'ballast' to increase the 'under-water'; weight.

Without it the top (above water line) is heavier than that below the water line and it turns 'turtle' (up side down)

 

If you add (say) 2 tons of extra metal, then you can in theory remove 2 tons of ballast.

My last NB had a 13mm thick base plate and because of the 'extra weight' it required very little in the way of ballast, so, the floor was lower and the head room greater.

 

Even 'huge' super tankers have to travel, either full of cargo - or - 'in ballast' where they pump millions of litres of sea water into the tanks to simulate being 'loaded' and to ensure the 'bottom' is heavier than the 'top'

 

Thanks, and after looking up more about ballasting I feel a little wiser.

 

I would imagine that removing the floor to remove any ballast would be a serious affair.

 

I was aware that empty tankers are filled with sea water from old articles citing pollution from the practice and even the odd historical explosion through mists and consequential static discharge.

[Neil2]

 

Thanks, and after looking up more about ballasting I feel a little wiser.

 

I would imagine that removing the floor to remove any ballast would be a serious affair.

 

I was aware that empty tankers are filled with sea water from old articles citing pollution from the practice and even the odd historical explosion through mists and consequential static discharge.

 

You raise an interesting point actually.

 

The reason narrowboats are/were routinely ballasted is to pull them down in the water to get under low bridges and also to create enough clearance for the bigger props that narrowboats tend to have compared to grp cruisers, for example. Ballasting was more of an issue in the days when boats were generally more lightly built than today, and I suspect than a lot of modern boats with their 10mm baseplates and heavier fit outs don't carry that much ballast at all. Some still see it as a good thing as movable ballast can be employed to adjust trim, though that argument won't carry much weight (sorry) with anyone who has ever tried to move concrete slabs around on a narrowboat...