Putting a plywood skin on the wooden bones of the deck

A task I was dreading was decking and the attendant 'hardship' of making patterns from thin hardboard to develop the deck panels from 9mm 5 ply, not a British Standard ply but 'Hardwood WBP ( water boil proof glue). It was suggested by the suppliers,Ferguson Timber, Acton, London, that it is likely that it is the same glue as is used in marine grade ply eg. BS 1088 except that the former's provence is not known and the layers of veneer are not of a single piece but rather assembled like a patch work quilt. This, however, is not apparent on the surface layers of the ply and the appearance was perfect. Allowing that there is a considerable price difference, that in my inexperience spoiling a sheet or two from poor workmanship or poorly cut out pattens was/is a distinct possibility and that this whole project is really something of a test bench makes using the cheaper item a reasonable choice.

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Here a single 2450 x 1225mm (8'x4') sheet is bent around the foredeck framwork with some difficulty in getting cramps to have points of purchase due to the overhang which was necessary to get the sheet close to the underlying frame. I suppose I could have use a Spanish windlass but found a stout rope around the sheet and the hull and its looped end over the jaws of a long friction clamp did the job and achieved the required apposition.

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Here interdigitating the side and foredeck panels is tricky and takes a bit of patience getting a reasonable fit as the hardboard pattern on the left shows. Not shown here but there was no attempt to match the ply colour as it is all going to be painted.There was no chamfering of edges here as the beam underneath was  wide enough to provide a good seal for both panels.

However the junction of the deck panels, here seen in the far lower left hand conrner of the lower of the two  pictures, had but a 20mm spar thereunder and so these I chamfered, fore panel overlying rear.

Sikaflex 291 Marine Sealant Trials And Tribulation On The Use Of

This shows the keel housing components seperate and in the order of assembly minus the bottom of the boat which will be between the housing and the lower compression plates. Both larger components are bent as best could be as to as least approach conformity with the bottom of the boat. It is the difference in conformity that require a good spread of 'filler' or sealant and the philosophy is essentially to put on more rather than less.

This shows the bottom of the boat ready to receive the housing. Cleaning is important and the maker of Sikaflex suggest that solvents leaving a residue be avoided. We used isopropyl alcohol, a good general spirit industrial cleaner. It might have been appropriate to have roughed the area with course wire wool but this was omitted. Perhaps somewhere in the back of my mind there was a worry of detritus from such cleaning getting into the proposed work.

The Sikaflex is 'toothpasted' on in runs of approx. 7mm thickness so each of the hole is surruounded.

The messy scene after bolting down with me inside and my friend under the boat. The central plates secured with 6mm ss hex head set screws/nuts and the marginal sections with 5 mm ss cuphead hex. recessed machine screws/nuts.

Pretty much the same situation under the boat. As we worked tightening the sealant bulged from the margins and from the holes yet unfilled with bolts in no uncertain manner. This Sika flex is expensive and it was a shame to see the waste but inevitable if we were to ensure filling of any potential points for water ingress.

This would logically suggest we should have worn gloves and it is advised by the Silaflex makers. However sensible gloves would have made the job impossible, given tactile finess, the shear number of scews to brought into place with attendent washer, spring washer and Nyloc nut, and the time for my friend under the boat to capture the head for me to tighten up. The work as a piece would have failed had the set time been exceeded and as it was it became quite difficult towards the last insertions of screws. Has we had cleaned our hands at short interval with mineral turps we might've not had the dreadful affliction to our hand seen here but time for that would have been lost to the job in hand. Normally the sealant is removable from the hands IF IT HAS NOT YET CURED. Thereafter one has to wait till it can be peeled or falls off from by mechanical means from attrition. Certain web advise suggested using razor blades but this did not appeal. In our case it took THREE DAYS to dissappear. We suffered no ill effects that we could ascertain though it is mentioned that skin reactions can occur. Of course the appearances made us feel like social outcasts.