N3541 Gruffalo

[National 12 Webmaster]

The life of N3541 Gruffalo.   Design: Uffa King, designed by: Uffa Fox in 1936

[Tim Gatti]

I started work on 'Gruffalo' in 2011, while I was a student at the International Boatbuilding Training College in Oulton Broad. My original intention was just to loft the lines of her hull, but as her shape developed on the lofting floor it seemed only right that I should carry through the process and actually build her, for the challenges of constructing a traditional clinker or lapstrake hull in this age of epoxy, plywood and plastic are the ultimate test of one's skill, patience and understanding.
I hope the following database entries will provide a background to the stages of the build process for coming to an understanding of how these boats were traditionally put together has been a real journey of enlightenment for me.
Stage 1: Lofting** - drawing out the lines of the boat full size on the lofting floor (**a term thought to derive from the large loft often built above the working area of a boatshed for this purpose)
Luckily, the Uffa King is one of the few early National 12 designs that still survives in print and the NTOA had a set of the original Yachting World drawings that were produced by Uffa Fox for people who wanted to build the boat at home.  The only line drawings I had to work from was a small set which can be found online on the N12 website.  By scaling up these drawings and combining them with dimensions from the home-build plans, I was able to develop a full size lines-plan and then work backwards to develop a full Table of Offsets for the design.
The Table of Offsets is simply a series of vertical and horizontal reference points, rather like a map reference, which with given dimensions, can be plotted on a grid to create the shapes of the hull when viewed from different points. Typically from this data it should be possible to draw out a Profile Plan - the hull viewed from the side; a Body Plan - the hull viewed from the bow through to the stern in sections, and a Half-Breadth plan - one half of the hull viewed from underneath showing the various waterlines and shape. (Only one half is drawn from the centreline out,as the other half will be a mirror image of it).
This stage took about two weeks to complete with another two days being spent transferring all the grids and lines to mylar film to preserve it for posterity!

[Tim Gatti]

Stage 2: Station moulds, templates and bevel boards
With the lofting complete the full-size drawings are then used as a basis to make the moulds which will determine the shape of the finished hull.
Made in softwood, or sometimes MDF, they will be erected at set positions or 'stations' along the backbone (keel & hog) of the boat and braced in position.
The attached photos show a station mould under construction, its shape having been 'lifted' from the lofting floor by laying nail heads along the shape required, then laying the mould timber
on top and pressing down hard.  The impressions of the nail heads left in the timber are then joined and 'faired' using a flexible batten, and the mould cut to shape. The process is normally carried out
for one half of the mould and a mirror image is then copied onto the other half resulting in a symmetrical pattern.

At the same time, MDF templates were made of the outline shape of key components like the centre-board case, stem, stern and quarter knees, the keel etc which would be used to cut and construct these items at a later date.
Other information taken from the lofting floor, using a bevel guage, were the bevels that would be needed to be cut into the stem and hog rebates to accommodate the planking,
as well as those that would be needed to be planed on the outer edges of the station moulds to reflect the correct curvature of the planking around them.

[Tim Gatti]

I WILL continue (in hindsight!) this build-log but in the meantime here's a photo of the nearly completed 'Gruffalo' at the RYA Dinghy Exhibition this weekend. (Photo by Jeremy Carey)



Just the thwarts to finish off, hull to varnish, floor boards to fit plus rudder and centre-plate to fabricate - oh, and proper rigging to install!



Expect to see her on the water at the Vintage Inland Champs in June, if not before.



Tim

[Tim Gatti]

Photo of 'Gruffalo' prior to launch and maiden sail on Tuesday 25th June 2013 at Yeadon Tarn W Yorks. 
The first Uffa King to be built for over 50 years.
Photo courtesy of Howard Chadwick

[Tim Gatti]

And under sail...
Thanks again to HC

[Tim Gatti]

View from aft - note crew waiting patiently with mugs of tea and stressed helm's attention elsewhere.
Sort your priorities Tim!

[Tim Gatti]

'Gruffalo' with Tim Gatti and crew Gill Bilton, on her way to winning Race 3 on Day 1 of the Inland Vintage Championships 29th June 2013.
(Thanks to John Cheetham for the lovely pic.)

[Tim Gatti]

And a beautiful photo courtesy of Kevan Bloor with 'Gruffalo' bolt upright on the beat - Gill Bilton doing a great job as crew in her first race in a National 12.