Stage 5: Decking begins on the new St Mawes Ferry
The wooden ferry, which will carry 100 passengers between Falmouth and St Mawes 364 days of the year, is very traditional in design but at the forefront of technology. The current St Mawes Ferry has a traditional pine deck - several pine planks, corked and sealed. But for the new ferry, Cockwells has plumped for a composite deck - two layers of plywood, cut specifically to fit the deck space with lapped joints and then sheathed in epoxy and glass.
Mash Derrick, Cockwells in-house designer, said the plywood sheets are actually cut to size on the deck itself, before they are glued to each other for strength.
He said: "A 'dry fit' of the deck is laid first. This involves 50 sheets of marine plywood being laid over the beams in two layers. The first layer is laid and cut to shape right up to the deck edge. This layer is screwed down to ensure a tight and accurate fit. Then the second layer of sheets is overlaid covering the seams of the first layer. These sheets are also screwed down and them trimmed. Each sheet is numbered and removed like a giant jigsaw puzzle."
When the plywood is ready to be fitted permanently, the underside of the first layer is painted to maintain the wood's condition then epoxy resin is used to glue the plywood down on to the beams as well as each layer of plywood to each other. The resin is never used before this stage as it becomes difficult to trim and shape the plywood pieces after they have been glued together.
Mash said the sheathing of the deck is a little like wallpapering a room. "The glass fibre comes in rolls and is cloth-like in texture. We lay it over the plywood, then it's wetted out with the epoxy resin. Large trowels are used to remove the excess resin and air bubbles. It's left for a couple of hours and is then ready to paint, " he said.
"There are two main reasons for using this method. The first is to increase strength, stiffness and durability of the deck, and the second is to provide a watertight deck as required by regulations from the Maritime and Coastguard Agency," Mash explained.
The 70.5 metre squared area should take two weeks to complete. The ferry will then be ready for the fitting of its superstructure - the deckhouse and wheelhouse.