Nelson & His World

Discussion on the life and times of Admiral Lord Nelson
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 Post subject: Batavia-ship in trouble
PostPosted: Fri Jul 27, 2012 3:54 pm 
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Joined: Sun Feb 17, 2008 12:28 pm
Posts: 145
In another thread on this forum, I informed you about the Batavia yard http://www.bataviawerf.nl/who-are-we.html
and my unfortunately, too short time, as volunteer working there.

In the local news last week a message appeared from Willem Vos, the gentleman who built the Batavia, that he wanted her taken into a dry dock as soon as possible. Reason for that is, that the Oak wood, she is made off, is starting to rot away. That means the part of wood, which is in contact with the water she is in. Since she has been launched in 1995, she has only been about seventeen years lying in the water. It seems a rather short time for a wooden ship. I can imagine the same thing happening to Nelson’s ships. How many years could they remain in the water, before they had to be repaired, so they could go back into the water again. Or did the copper plates on the bottom of the ship protected the wood for/against rotting away.

I am sorry if this question has been asked before, but my eye-side is still causing problems, so I still have difficulty reading.

Sylvia


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 Post subject: Re: Batavia-ship in trouble
PostPosted: Sat Jul 28, 2012 11:48 am 
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Joined: Sat Feb 23, 2008 9:11 am
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Location: Stockholm, Sweden
Hello Sylvia,

Sorry to hear about the problems with Batavia and that she is showing signs of rot, which might be from various reasons.

Seventeen years is actually quite a long time before a wooden ship needs to be refitted. The ships of the British fleet, and those of other nations both before and after the Napoleonic Wars, went in for periodic refits throughout their lives. Those on the Victory, for example, were about ten or so years apart, although many of these were largely needed due to repair battle damage and to make improvements. However, they could also be required because of age, stress of weather, as well as rotting timbers. Refits were classified as small, middling, and large or great, depending on the damage to be repaired. It was also very expensive, and in today's figures could be the equivalent of several millions of pounds. Spending on defence has never been cheap, especially in war time!

Rot was a major factor requiring a docking, but it was very often caused by fresh water rather than salt, the water seeping down through the hull from above. During the reign of Charles ll, Samuel Pepy's the Secretary of the navy, paid one of his visits to, I believe, Chatham Dockyard, and reported that toadstools were growing in the holds of several ships moored there. This was obviously due to rot, but it may have been caused by fresh, i.e. rain, water finding it's way down through the timbers. So, the problem is not a new one! One idea that shipwright's often used to reduce it was to leave small spaces in the internal hull timbers, into which salt was packed. I'm not sure how much effect this had, but it shows what lengths they went to in order to alleviate the problem.

It would seem that rot often set in during construction, perhaps though the use of green timber or that which was damp internally, and there were instances of ships being condemned after just a few years due to this. Oak timber for shipbuilding was not normally considered suitable unless it was at least 100 years old, but obviously there were instances when much younger timber was used, and this may have been a factor. I don't know how old the timber was that was used on Batavia but, with the scarcity of grown oak today, I doubt it was anywhere near that age. For some time now other woods have been found to replaced it. One of these is an African wood called iroko, which was seen some years ago as the ideal substitute. Of latter years, however, it would seem as though it has not been found to have the same properties as oak, and has been causing problems, and perhaps rot. Iroko has been used in the replacement many of of Victory's timbers, but I believe it is now thought not to have been a good solution.

Coppering had not been thought of when the original Batavia was at sea, it being first invented in about 1760. Even then there were problems, primarily by the use of iron bolts, causing an electrolytic action between the two metals. When this was understood, copper bolts were substituted, and the problem diminished. Coppering ships in earnest then commenced at about the time of the American War of Independence. Victory was first coppered in about 1780 and thereafter was re-coppered, I think two or three times. The idea of coppering was actually to rid ship's hulls of the teredo worm, which was picked up in tropical waters, and which caused damage by burrowing into the timbers. I don't think it prevented rot, and there are many instances where ships timbers were actually rotting behind it, and probably thus one reason why ships were re-coppered during their lifetime.

I don't know what was used below the waterline on the present Batavia, perhaps modern marine growth retardant (and environmentally acceptable) paints. The original could have been treated with all sorts of horrible concoctions to preserve the timbers! One problem could just be that she is moored alongside. Strange as it may seem, but vessels that actually go to sea appear to last longer, largely because they have to be maintained and be made seaworthy to a certain standard.

I hope they manage to rectify the problem.

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Kester.


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