back to the vasa museum

[pilvikki]

i've always liked the vasa ship, from the first time i was on it in 1965; which now sounds crazy for you're not even allowed to use a flash to take pictures of it, never mind tramping all over. they've expanding the museum further and there are more artifacts on display with the original in a glass case and a replica next to it. then they have made a ....um, what would you call it..? ok, there is an iron pipe you can lift to demonstrate how much a musket weighs. and never mind carry it! how the bloody hell do you aim something that heavy?

the sip's hull was 60 cm thick to withstand connon blasts, which sailed right through anything 3" thick and oak... most guys were killed not by the cannon balls, but the wood splinters they shattered. to add more carnage, the canonballs were not always round balls, but had spikes inserted for maximum damage. nasty business...



they replaced the rusted out iron bolts with iron bolts when they put her together ("world's biggest jigsaw puzzle"), but now they're damaging the wood with rust, so the thousands of them are being replaced with steel bolts. how the rust is damaging wood, i don't get, but will look that up, being the nosy sort.

ah, the website's a bit better now: http://www.vasamuseet.se/en/visit/vasa-in-one-hour

[yogi]

That's one hella ship that Vasa is. I can see rust staining the wood but I'm not sure it would actually deteriorate it. Stainless steel bolts would look pretty, so that would be my first choice. What could it be? $10/ bolt? Cheap, considering.

[pilvikki]

I asked about the rust and it softens the wood, which then loosens the bolts. then I found it on their page:

The bolts holding Vasa together are corroding and thereby weakening the ship's structure. To improve structural stability, we are now replacing around 5000 bolts. The work is reckoned to be finished by late 2017.

Vasa was originally held together with iron rivets which corroded away during the hundreds of years of burial. In order to raise and give structural stability to the ship, more than 500 mild-steel bolts were inserted into the original rivet holes in the 1960s.

Over time, the bolts have corroded and the ship has deformed. The corrosion weakens the bolts and they have deformed along with the ship. Corroding iron also causes chemical reactions in the wood which can result in loss of wood strength.

some bolts are 6' long....

[yogi]

There may be other solutions, but anything I do around the house that faces the weather needs to have stainless steel underpinnings. Doing that to Vasa would take away from it's authentic look, but it would preserve it's structure. I'm certain there are plastic bolts just as strong as steel. I guess it all depends on how serious they are about preserving things.

[pilvikki]

just thought of something: since they've recovered 98% of the ship, i'm wondering why none of wood didn't float up and away...? it's mostly black oak.

[yogi]

I can't imagine a wooden boat holding itself together after being submerged for such a long time. The engineers who orchestrated that feat were geniuses. Then again, they recovered 98% of what was there. Was it all there?

Does black oak actually float? Yes, here's why: https://www.mansfieldct.org/Schools/MMS ... ensity.htm

[pilvikki]

ah, I tried looking it up, but failed. thanks! black oak, I think was at .75 or so, so... why did none of it float away?

well, it was loaded for bear, but at least its boat out to have wandered away... maybe it was all well stowed and nothing actually broke away before being water logged?

[yogi]

Apparently even rusty bolts will hold a boat together. If the underwater currents are not too strong, there would be no reason for the boat to fall apart. The big question in my mind is why it did not fall apart when they retrieved it. THAT is a small miracle.

[pilvikki]

well, they tunnelled beneath and used heavy duty pipes, 6 I think?, to keep it from breaking up. so I suppose the rusty bolts still held?