2.7 mm steel plate thickness

[David Mack]

4 hours ago, Neil2 said:

Bear in mind that sea going boats are generally built as light as practicable  - to be faster, more efficient, greater payload etc. but they also tend to be better protected against rust.  The plating can be as thin as you like if you don't let rust get a hold.  OTOH narrrowboats have to be inherently heavy to pull them down in the water as they are basically just a steel box so there's no real incentive to use "thin" plate unless it's on cost grounds and a jumbo baseplate can avoid the need for ballast - even more internal space.  The use of thick plating has created the tendency to associate thicker plating with better corrosion resistance, which is true up to a point, but it doesn't mean a boat built with 1/8 plate or even 1/16 is unsafe, so long as the hull is protected and maintained.   

 

And seagoing boats don't spend most of their lives dragging along the sides and bottom of the waterway, so will suffer less damage to their hull paintwork, and less wear on the steel.

[X Alan W]

A lot of "Lumpy water boats are built with more/closer spaced frames so the plating can be thinner ( more support) some navy ships are built with light /for size plate & end up looking like starving orphans or the late built "Dustbin NB's " It would ta ke a good blow to puncture 2.7mm plate if in decent condition

[Alan de Enfield]

30 minutes ago, X Alan W said:

A lot of "Lumpy water boats are built with more/closer spaced frames so the plating can be thinner ( more support) some navy ships are built with light /for size plate & end up looking like starving orphans or the late built "Dustbin NB's " It would ta ke a good blow to puncture 2.7mm plate if in decent condition

Agreed.

Car body panels tend to be 0.6 - 0.8mm thick (depending on manufacturer) and they can take quite a beating, yes they can get crumpled and dented, but it takes a lot to actually 'rip' them.

Now image a piece of steel 4x thicker.

 

Take a piece of 2.5 or 3mm plate steel and try and bend it, hit it with a hammer or belt it with a hammer & chisel - its much tougher than you may think.

The 'industry' has led everyone to believe that it has to be thick - it doesn't.

Edited August 7, 2018 by Alan de Enfield

[crosser]

springers are not alot more than 3mm and look how many of them are still going strong..  people do panic ...  ive seen a few sunken narrowboats and only a tiny amount are from damaged hull...  and cant think of the last springer i saw sunk from hull corrosion or hull damage.. nearly always rainwater or stern gland failure..

 

[Kieron G]

My boat is similar age and also 1/8 inch construction.  I had to cut sections out and fit plates in where water had sat inside for years and corroded through ( when the boat was derelict on hard standing ) . Never had a survey but I know there is some pitting inside the hull. The important thing for me is that I can access the inside of the hull in all areas. I insure 3rd party with basic boat insurance at a level where I can use tidal waters to access the inland waterways which I often do.