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History's Hinge - 'Ain Jalut

[moneypenny]

Doc, you said maybe there were no survivors of the wreck. Am I correct that if there had been survivors and they made it to a location where they could report the wreck, and salvors were sent out, that they would have salvaged as many cannons and anchors as they could since the water is so shallow?  Or would they only have concerned themselves with cargo and valuables?
moneypenny

[Diving Doc]

In the New World the cannon and anchor were worth their weight in gold and a whole lot easier to recover than the scattered treasure using Indian divers. I imagine the starboard side of the ship was visible at low water for a very long time after the disaster. Seems almost certain, even if they went for the treasure first, they still would have salvaged the anchors and cannon, if anyone knew where it was.

French cartographers wrote in the 1750's of ship wrecks they had sighted years before as still being visible. Apparently this location was lost if there were survivors.

Doc

[Diving Doc]

An interesting picture of the protective bronze hawse. This shipboard item was the fairlead for the anchor line and prevented chaffing the rode in two. Very useful, I would say. This was found and left in the area of the Port Bower anchor.
Doc

[moneypenny]

Doc,  isn't it amazing that something from over 300 yrs. ago can lie there and not degrade at all since it is not near a more noble metal, and thus doesn't degrade on the sea bottom?  Looks like it was just put there a few years ago, huh?   
Moneypenny

[Diving Doc]

Moneypenny,
It appears that the quality of the alloy of this casting was very good indeed although it does show some corrosion from electrolysis.
Regards,
Doc

[Solomon]

This reminded me of a story regarding corrosion:
Iron pillar withstands corrosion for 1,600 years

Solomon

[Diving Doc]

What an amazing story Solomon! You are just so full of wonderful true tales.

I digress,
I answered Moneypenny much too quickly. The Spanish, since they usually used lead plating on the hulls of their ships, had to use bronze gudgeons and pintles or suffer the misfortune of having their rudders fall off because the lead created a battery with the sea and destroyed iron fittings. The light corrosion on the bronze fitting pictured would suggest the interaction with a nobler metal, silver perhaps. Time will tell.
Cheers,
Doc

[Diving Doc]

This picture illustrates the sheathing with the antifouling between the hull. Pretty rotten old ship she was. The sheathing looks almost new. I carefully recovered the hull with sand after taking the picture. Note too the line of old tar caulking standing proud. The entire inside of the hull had been tarred. The Spanish had a huge pitch lake in Trinidad.
Doc

[moneypenny]

Going back one post to the info on the metal of the hawse pipe, Doc, you stated:
 "The light corrosion on the bronze fitting pictured would suggest the interaction with a nobler metal, silver perhaps."   
Are you saying that the fact that the bronze is corroded at all is because of being near a nobler metal? Does that mean that if it wasn't near a nobler metal, it would have remained in as good a condition as it was before sinking?
   And yeah, I bet you hope that nobler metal is silver! 
moneypenny

[Diving Doc]

I recall a bronze cannon recently recovered in the UK by NAS. The part that was exposed to the surf was polished away to fine finish but the part that was buried retained the decorations. Moneypenny, it all depends on the correctness of the alloy. Sometimes old bronze cannon were recast and sometimes they used Church Bells. In cases like these there were a lot of impurities and if left in the sea a lot of corrosion would occur.

[Diving Doc]

What could be more exciting than looking down and seeing this when all you were looking for was lobsters?
Cheers,
Doc

[Diving Doc]

I have already mentioned the use of thin lead sheeting by the Spanish on their vessels in the New World. Let me give you an example. This is a piece of lead sheeting formed to cover a 90 degree corner. Since I found this in close proximity to the rudder gudgeons I assume that it might have covered it. My hand gives a size comparison and I do have large hands.
Doc

[Sovereign]

Doc, I can see that using lead had some simple advantages, in that it was maleable and so on, but don't yachts use lead ingots on the hull, as anodes, precisely because they corrode?
Thanks!

[Diving Doc]

They sure do but they have something that the Spanish never had, an electrical system needing grounding. The lead sheeting worked well enough if applied when the vessel was new but in this case it is obvious that the vessel was worm eaten prior to the anti-fouling and application of cedar (?) sheathing and then the lead. There were pieces of lead sheeting everywhere in the vicinity. As long as the Spanish used bronze ftg.s it worked well. The accounts of Spanish ships losing their rudders are numerous, the why of not using iron ftg.s on a lead plated vessel.
Cheers,
Doc

[moneypenny]

Excuse me gentlemen, but I must insert my 2 cents here. As a sailor, I am fairly familiar with the chart of metal activity, and must say that it is ZINC, not lead that is used as an anode under boats to be used up.  Lead is actually a bit higher on the chart right next to copper, and it is above iron, so is less reactive than any of those 3.  In fact, many sailboats have lead keels, and we wouldn't want them being constantly eaten by electrolysis.      Please forgive the interruption. 
moneypenny