Grown frames

Hi i have just started a rebuild on a 20 ft Porthleven cove boat.
Her construction is both grown & steamed frames, which both need replacing along with 3 planks.
I am looking for any info with regards to the replacment of the grown frames as i have never done this before.
Regards Mark

 

Ah, grown frames, young fellah me lad...
A long, long history - going back to Elizabethan times. There was an official post created by that strange lady 'With the heart of a man...'
Chaps would wander through the English forests looking for suitably shaped timbers (branches, roots, etc) and hammer a 'royal tag' in them ready for future harvest. For a non-royal ship builder to remove them was punishable by hanging. These timbers were used to build the various fleets which faced those dreadful foreigners - the Spanish, French and Dutch...
As you probably know, many of those same timbers can still be seen in some of the older houses, barns and churches along ther English coastline as roofing beams and trusses (after the fleets had been broken up, or wrecked.)
However to answer your question - how do you replace them - if that was the question: Contact your local Forestry Commission (with hardwood forests in its care), or country estates with friendly gamekeepers/warreners or what have you, and ask if you can have a squint at what's available. Explain your needs - and with luck you'll get a sympathetic hearing. However freshly gleaned 'shapes' will need at least a year's seasoning before use. But, rest assured - grown shapes are up to 300 percent stronger/more reliable than steamed or laminated ribs.
Alternatively - have a tour of local timber yards and saw mills. You can often find the ideal shape tossed in a corner as 'scrap', which eventually will be converted to 'logs'.
A lengthy process either way - but worth the time and trouble - and you learn a lot of practical knowledge about timbers and their use.

 

I have managed to find a good tree or two for the timber & there be no royal tags on um,as they have fallen in the tidal river im reconing they will be well salted & also "wreckers rights" a cornish tradition to have what the lord provides.As well as this being a good source of free wood its also from the same place the boats timbers originaly came from.
The problem I am anticipating is in the fitting due to bevle of the planks, I have made fore & aft templates of the futtocks but wonderd if there was a better way to get um to fit snug to the planks better than "guesworks the best work.
Kind regards Mark

 

Mark - there is - or was when I was in the UK - a strange tool/gadget which I found invaluable for awkward templates - especially when refitting timbers to existing 'shells'. Can't think of its name (if I ever knew it) but it is a base plate of metal about half an inch thick with hundreds of steel pegs in ranks which can be pushed through to copy shape of object its laid against. It comes in squares - oblongs - and handy foot long, 2 inch wide strips. Probably called a 'template maker'
Other than that - I used strips of plasticine pressed against the desired shape, and used that as a 'rough' template - then sandpapered until a perfect fit.

 

They use to have "crook farms" . The trees where tied or chained to make them grow in appropiate curves. American Indians made bows with that method.

 

The tool for copying shapes is called a contour gauge. They'r available from woodworking shops. Mine cost about ten bucks for a twelve inch one. they now come in plastic, which is great for the marine environment.

BTW, if youre using waterlogged (cured?) wood you may want to look into using PEG ... poly ethylene glycol ... it replaces the water in the wood cells and works as a preservatinve. Works for green wood as well. It's the stuff they use on the ancient sunken vessels that they've beeen hauling from the brine. The first I heard of it was the Scandenavian vessels they found. Been thinking abut using it, but still researching. It comes in a variety of molecular weights ... goes from liquid to wax as the size of the molecule increases. Trying to get some formulations as we speak.