VicS
Well-Known Member
Re: H2S ..... wasn\'t me that first said H2S ....
H2S is formed in anaerobic conditions when (certain) bacteria "attack" the sulphates in the water to obtain oxygen.
It is the first step in a chain of events that is now causing problems with preserved wooden ships. There is a lot of info that you can find by Googling about the Vasa which sank in Stockholm Harbour in 1628, the lagest part of a centuary later than the loss of the Mary Rose but with many similarities. It was raised in remarkable condition in 1961 and has been restored rather than merely preserved like the MR.
The good condition is attributed to low temperatures and high pollution levels but the conditions led to H2S being produced and absorbed deeply into the timbers. Subsequent decompostion of the H2S deposited elemental sulphur in the wood. Once raised oxidation of the sulphur, catalysed by iron from the rusting fastenings, has lead to the formation of large quantities of sulphuric acid within the wood which now threatens the ship. In the short term attempts are, I believe, being made to neutralise the acid already formed but reseach into a long term solution is ongoing. The latest idea that I have heard of is to chelate the iron to prevent further oxidation of sulphur occuring.
The MR is now of course suffering from the same problems.
Apologies to everyone for deviating so far off the original topic and also if it is something you already new about.
If you or any one else did not know about it then, as mentioned earlier, there is loads to find on various websites, not only about the sulphur problem but about the history of the Vasa, her sinking, her recovery and her restoration. A big difference to the amount of information about the MR, at least the amount I've been able to find!
Apologies also for any inaccuracies that may have crept into the above and for not now being able to give urls for the Vasa webites.
H2S is formed in anaerobic conditions when (certain) bacteria "attack" the sulphates in the water to obtain oxygen.
It is the first step in a chain of events that is now causing problems with preserved wooden ships. There is a lot of info that you can find by Googling about the Vasa which sank in Stockholm Harbour in 1628, the lagest part of a centuary later than the loss of the Mary Rose but with many similarities. It was raised in remarkable condition in 1961 and has been restored rather than merely preserved like the MR.
The good condition is attributed to low temperatures and high pollution levels but the conditions led to H2S being produced and absorbed deeply into the timbers. Subsequent decompostion of the H2S deposited elemental sulphur in the wood. Once raised oxidation of the sulphur, catalysed by iron from the rusting fastenings, has lead to the formation of large quantities of sulphuric acid within the wood which now threatens the ship. In the short term attempts are, I believe, being made to neutralise the acid already formed but reseach into a long term solution is ongoing. The latest idea that I have heard of is to chelate the iron to prevent further oxidation of sulphur occuring.
The MR is now of course suffering from the same problems.
Apologies to everyone for deviating so far off the original topic and also if it is something you already new about.
If you or any one else did not know about it then, as mentioned earlier, there is loads to find on various websites, not only about the sulphur problem but about the history of the Vasa, her sinking, her recovery and her restoration. A big difference to the amount of information about the MR, at least the amount I've been able to find!
Apologies also for any inaccuracies that may have crept into the above and for not now being able to give urls for the Vasa webites.
