This is the second of my talks in the USA. It focuses a bit more on construction and some of the methods that can be used to keep a boat light and simple, but very strong and stiff.
It also discusses how there is a “creep” in boatbuilding and design that increases the weight of boats way over what is really needed for a strong structure.
The talk does discuss the sizes of normal boatbuilding joints and how I generally think scarf joining plywood is a waste of effort (unless you like that sort of thing!)
This diagram will make some of the talk more clear. It shows how all plywood joint sizes evolve from the plywood thickness and are simple multiples of that thickness (“t” in the diagram). If two different thicknesses of ply are used they only need to be the right size for the thinner ply.
Note that the epoxy fillet is made with a high strength gluing additive – not a low density powder.
These are for plywood joins only. If doing timber scarfs for spars and other high strength applications then the scarfs usually need to be 8 times the thickness of the timber.
Also the fillets have a limitation that as the boat gets bigger they become too big and expensive and it becomes cheaper to either do them in timber or make smaller fillets and glass them with biaxial glass.
Making plywood joints bigger than what is specified above is a waste of materials and labour and makes the boat heavier than it needs to be.
Anyway … cut to the chase again – this talk is about 40 minutes and is the second of the three. Click on the play arrow or download below
Or you can download here
Talk on Boat Structures and Design Part 1 – Portland OR
Further information can be found:
The PDRacer that helped formulate a lot of thing thinking about performance with low cost
Making sailboat rigs work better – mostly lug, lateen and sprit boomed rigs, but relevance to all cheap sailboat rigs.
