Jay Greer
08-02-2006, 01:24 AM
Since there seems to be a bit of confusion regarding laid decks, I offer these humble notes.
How a deck will best be laid dependends on the structure beneith it.
The traditional deck for a boat some thirty feet on deck or more, often, consisted of bronze X strapping in way of the mast partners and a cedar or eastern white pine underlayment of bead edged T&G.
This was most often overlaid with canvas set in shellack. Covering boards were, on best built boats, connected by hook scarfs. The reason for this was that, a boat deck was built to work in harmony with the hull beneith it. The strong sorrounding ring of the covering boards, in conjunction with the other strengthening components of the deck structure, acted like the rings around the domes of classic Roman and Italian domes. The ring is a strength component in resisting the deflection of the arched deck beams in conjunction with the forces created by the driven cotten caulking in the deck seams.
These structural forces resist both wracking and hogging of the hull structure and materialy add to the stiffness of the boat while adding the least amount of weight per square foot of deck area.
Modern hulls do not necessarily need this form of construction if they are either built of strip planking or of epoxy saturation methods of construction. However, the elimination of traditional deck caulking can lead to moisture invasion if meticulous sealing of edge grain and plank under layment bedding are not adhered to. More often than not, the modern teak deck will last only a fourth to a third of the time that a traditional deck will. The cost of rebuilding of such decks can be nearly twice to three times the cost of a traditional laid deck. This is due to the extensive labor involved with the removal of the decking which, most often, requires the removal of the sub deck as well. Often, there is also rot involvment in beams or sheer clamp components as well.
The traditional laid deck is best laid of strakes that are nearly square in cross section and stand a quarter of an inch or so obove the covering boards. This will insure that there is plenty of material for resurfacing over the years to come and channels water more efficinently to the lee scuppers. Decks of this type are laid with V shaped caulking seams in order to easily accept the driven caulking cotton. It is the cotton caulking and not the seam compound that insures a tight deck. If one is planning to use traditional oil based seam compound. There are still a few on the market. "Jeffreys Marine Glue" is one and Pettit also makes appropriate oil based seam coumpounds. Heating the material in a double boiler will allow it to be poured into the caulking gun more easily. Seams should be taped off primed with a mixture of bee's wax and turpentine prior to driving the cotton caulking. On light decks caulking cotton can be forced in with a seam wheel followed by driving with a light iron and mallet. The cotton should then be primed again with the bees wax and turpentine mixture. Once it has set up, the seams can be payed with oil based compound. Often a run over with a stiff putty knife will assist in setting the paying. Once the seams have set up sufficiently, the tape can be removed. Oil based seam compound applied in this manner will last for many years. Should a crack open up, it is a simple matter to run a hot iron down it which, will melt the compound back in place.
If one chooses to use one of the modern polysulfied compounds that are currently on the market, the seams should be prepared with a square fillister rabet and not caulked with cotton. However, one should then be willing to accept the fact that the deck will not be as rigid as a caulked one would be. And, once a seam separates, it is not so easily repaired.
JG
How a deck will best be laid dependends on the structure beneith it.
The traditional deck for a boat some thirty feet on deck or more, often, consisted of bronze X strapping in way of the mast partners and a cedar or eastern white pine underlayment of bead edged T&G.
This was most often overlaid with canvas set in shellack. Covering boards were, on best built boats, connected by hook scarfs. The reason for this was that, a boat deck was built to work in harmony with the hull beneith it. The strong sorrounding ring of the covering boards, in conjunction with the other strengthening components of the deck structure, acted like the rings around the domes of classic Roman and Italian domes. The ring is a strength component in resisting the deflection of the arched deck beams in conjunction with the forces created by the driven cotten caulking in the deck seams.
These structural forces resist both wracking and hogging of the hull structure and materialy add to the stiffness of the boat while adding the least amount of weight per square foot of deck area.
Modern hulls do not necessarily need this form of construction if they are either built of strip planking or of epoxy saturation methods of construction. However, the elimination of traditional deck caulking can lead to moisture invasion if meticulous sealing of edge grain and plank under layment bedding are not adhered to. More often than not, the modern teak deck will last only a fourth to a third of the time that a traditional deck will. The cost of rebuilding of such decks can be nearly twice to three times the cost of a traditional laid deck. This is due to the extensive labor involved with the removal of the decking which, most often, requires the removal of the sub deck as well. Often, there is also rot involvment in beams or sheer clamp components as well.
The traditional laid deck is best laid of strakes that are nearly square in cross section and stand a quarter of an inch or so obove the covering boards. This will insure that there is plenty of material for resurfacing over the years to come and channels water more efficinently to the lee scuppers. Decks of this type are laid with V shaped caulking seams in order to easily accept the driven caulking cotton. It is the cotton caulking and not the seam compound that insures a tight deck. If one is planning to use traditional oil based seam compound. There are still a few on the market. "Jeffreys Marine Glue" is one and Pettit also makes appropriate oil based seam coumpounds. Heating the material in a double boiler will allow it to be poured into the caulking gun more easily. Seams should be taped off primed with a mixture of bee's wax and turpentine prior to driving the cotton caulking. On light decks caulking cotton can be forced in with a seam wheel followed by driving with a light iron and mallet. The cotton should then be primed again with the bees wax and turpentine mixture. Once it has set up, the seams can be payed with oil based compound. Often a run over with a stiff putty knife will assist in setting the paying. Once the seams have set up sufficiently, the tape can be removed. Oil based seam compound applied in this manner will last for many years. Should a crack open up, it is a simple matter to run a hot iron down it which, will melt the compound back in place.
If one chooses to use one of the modern polysulfied compounds that are currently on the market, the seams should be prepared with a square fillister rabet and not caulked with cotton. However, one should then be willing to accept the fact that the deck will not be as rigid as a caulked one would be. And, once a seam separates, it is not so easily repaired.
JG