By Dave Johnston
Weekend 13/14 August 2016
Usually things conspire against us but this week we were dealt a real handful of aces; bright sun, a boatload of divers, sea not too rough or windy (flat as a millpond on Sunday) and excellent visibility of 5-6 m. It was probably the best weekend’s diving on site in many, many years and it enabled us to do a great deal of useful work with ease, speed and accuracy.
Two more datum were installed on timbers around the excavation area to complete the initial set and these were then all measured in to each other and to several existing datum around the site. The excellent visibility made it very quick and easy to move between the points taking measurements. We are also trialing different types of stainless steel eyes to see which are most durable and secure – we have used a combination of stainless steel vine eyes and stainless steel eye-bolts. The latter have a slightly longer and thicker shaft and seem to “bite” into the timber better, though time will tell.
We also tested a special underwater glue called “Underwater Magic” which is designed for underwater repairs to swimming pools etc. but also supposed to work in marine environments. The idea was to see if we could attach stainless plates onto the top of the cannonball pile and onto one of the cannon to give clearly defined, easy to locate monitoring points. Having scrubbed away all the marine growth over a small area to expose clean concretion, the glue, which comes in a standard cartridge was applied. It was very stiff and sticky and it got everywhere, rapidly ruining a pair of diving gloves, but it seemed very reluctant to stick down onto the concretions. Having left it 24 hours to set, one of the fixings seemed reasonably secure though unlikely to withstand much stress from a tight survey tape, the other was already starting to come loose. We live and learn.
Artefact-wise, it was also a very successful weekend. On Saturday yet another pair of dividers were located, surveyed in and recovered. these were in near perfect condition and represented a design which we have not seen before. Very interestingly, this pair were constructed entirely of brass, whereas all other pairs recovered to date have had steel tips for durability (long since corroded away). The centre “pin” of a shoe buckle was also located, surveyed in and recovered. Both of these finds came from inside the hull, showing just how much material is being uncovered. On Sunday, a section of leather shoe was added to the haul.
Most excitingly, wedged between the timbers on the starboard side of the hull, a timber artefact had been noticed on previous dives and conditions allowed a more thorough investigation. The object was cylindrical and some 60 cm long by 15 cm in diameter. Careful hand fanning of the surrounding sediments revealed that one end was solid and the other hollow, that it was hollow at on end and had carved / tuned reinforcing rings on its outside.
Dan, our archaeological advisor identified it as a near perfect powder canister or ‘salt box’, used for transporting charges of gun powder from the powder store to the gun decks. The process of excavation was videoed and the artefact very gently removed, wrapped in a heavy duty plastic bag and goody bag and recovered to the surface where it was further wrapped in a plastic sheet and bound loosely with rope to prevent it collapsing out. Such was the fragility of the artefact that, despite perfect conditions for another dive, the priority was to get it ashore safely and into water to help support it.
Dan recorded the dive which can be found HERE
We hope we can now hand it to The Mary Rose Trust to excavate its contents in a controlled laboratory environment and then start the conservation process. These cartridge cases were usually made of a soft timber like poplar and so is very fragile.
All in all a belter of a weekend!
Photographs by Dan Pascoe/Iain Grant