the keel stringers are sitka spruce 35x45mm so we doubled up the 35x22 stringers that we use everywhere else by glueing them together with spabond. we found it easiest to do the glueing in situ. and instead of using a lot of clamps we hold the two 35x22s together with plastic nails whilst curing. the nice thing about the plastic nails is that they sand of really easy and it doesn’t matter if you cut them with a saw or plane. also they don’t corrode.
on the pictures below you can see the keelstringers after they were glued in and bevelled to receive the keel panels.
towards the stern of the hull the keel kicks up and meets the single longitudinal stringers that run parallel to the waterline.