The caulking of the hull
Two shipwrights at work until april 2011.
On october 15th, a team of two shipwrights from the Chantier Bernard has started the caulking of the underside - the part of the hull under the waterline. The caulking of the topsides -above the waterline- has in the meantime already been done.
The caulkers use a 100% traditional technique that consists of closing the seams (sealing) between the board planks with tarred hemp to render them watertight. Two kinds of hemp are used: braided hemp threads ("bitord") and oakum (hemp in bulk).
The caulkers spin the oakum into ropes of different thickness, depending on their final function. The spinning is done by hand and the method is similar to the one used by caulkers at the age of the building of the original Hermione.
The hemp is hammered between the seams of the planking with a mallet and a caulking iron of which the thickness is chosen according to the size of the seam. Multiple threads or cordons of hemp can be necessary to achieve a good sealing of the joints.
This long-term operation takes about 4000 working hours (topsides and underwater hull). Only for the underside, there is about 2400 m (1.5 miles) of seams to caulk...
Once the caulking is finished, the whole hull is grouted to ensure a complete filling of the joints.
