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Archiver > Mariners > 2004-08 > 1091531162


From: "Cameron" <>
Subject: RE: [Mar] Copper-bottomed
Date: Tue, 3 Aug 2004 21:06:02 +1000
In-Reply-To: <71apg05ojp8c01qrda4529pskkmsudom1l@4ax.com>


Hello Paul,

Thanks for this - a most interesting account!

All the best

Sybil

-----Original Message-----
From: Paul Benyon [mailto:]
Sent: Sunday, 1 August 2004 6:33 PM
To:
Subject: Re: [Mar] Copper-bottomed

Hi Sybil

I understand that the idea of a copper bottom was originally to act as
a defence against the Teredo worm and at the same time reduce the
resistance caused by the various weeds etc which grow on the bottom of
vessels thus reducing the speed of the vessel through the water.

This being the case I would have thought that the copper sheets would
have covered most of the areas of the vessel which were submerged for
most of the time. A very expensive operation, with the Navy
invariably removing the copper from the ships it sold and always from
vessels which went to be broken up - this for many years after its
introduction as an almost standard feature in the 1780s.

As it happened the copper bottom did nothing to keep out the worm,
which found the shelter provided by the copper much to its liking.
What kept the worm out was the hot tar and felt that was used on the
hulls to act as an insulation from the copper, presumably to prevent
contact with any iron objects and the consequent deterioration caused
by the chemical interaction between the two. It took the loss of 4
ships-of-the-line and 3,500 men to discover this.

However, reports from commanding officers suggested that vessels
fitted with copper bottoms handled much better, presumably at the time
when they would normally be growing weed etc. on the bottoms and their
performance would be expected to deteriorate ?

My thanks to Alexandre Monteiro who provided much of this information
on another list, excepting he doesn't specifically answer your
question, and hence my supposition as to how much of the hull was
covered with copper.

Regards

Paul

On Sat, 31 Jul 2004 22:48:37 +1000, "Cameron" <>
wrote:

>Hello,
>
>Can anyone help me with this question please?
>
>If a ship is being sheathed in copper in the mid-1780s, how much of the
>ship does the copper cover?
>
>Does it extend above the water-line?
>
>Best wishes
>
>Sybil Cameron
>
>
>
>
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