Eclectic thinking - heart of the National 12's philosophy
by Jeremy Carey 26 Feb 2013 07:29 GMT
Stand B28, 2-3 March 2013
Tim Gatti's brand new 1936 Uffa Fox designed National 12, Uffa King © Tim Gatti
The National 12 class is steeped in history, yet at the same time is at the forefront of dinghy design and development. This year's RYA Dinghy Show will perhaps be the best opportunity ever to see the depth and breadth of thinking in a class with an obvious passion for these 12foot dinghies. On the stand we have two of the latest built boats from opposite ends of the classes thinking.
Firstly, having not yet even had the chance to hit the water in N3541 'Gruffalo'. Passionate boat restorer and sailor, Tim Gatti will be displaying his brand new 1936 Uffa Fox Designed Uffa King.
In Tim's words:
"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."
And so, nearly two years later, the photo above gives you a gentle tempt at what should be a stunning portrayal of traditional boat building skills. Having yet to see it myself, I'm champing at the bit to feast my eyes on this contrasting work of modern and traditional history.
To contrast N3541, the National 12 stand will also be displaying N3543 'DB Cooper' the most recent development in the cutting edge of design within the class. Over recent years Jo Richards' 'Dead Cat Bounce' design 12 has been taking most of the glory and the new thinking on this latest 'Hijack' design by designer Dave Hollom, has taken a quite radical approach from the thinking that has previously dominated the lines of 12s.
Dave Hollom's approach to 'Hijack'
'Hijack' represents a completely different approach to dinghy design. Whereas, current dinghy design invariably utilises a U section this design uses a V section.
Contrary to popular opinion, a U section does not necessarily represent the minimum wetted area for a given volume. It depends on the other design criteria and taking these into account, the V section may well end up with less wetted area. A V section also has less wave drag for a given beam/depth ratio and also has the advantage of having less waterline beam, within the rise of floor measurement, which reduces the sections naturally low wave drag even further.
Whilst the design utilises a V shaped midsection this blends into a pronounced U at the bow and a soft U at the stern. The idea here is to put more buoyancy into the ends raising the prismatic which reduces wave drag at most of the speeds we are interested in. Normally, a rise in prismatic is accompanied by a coarsening of the waterlines but, because of the narrower waterline beam the bow waterlines are no coarser than those of U sectioned boats.
Reducing wave drag, besides allowing the boat to sail faster at displacement speeds, also allows the boat to reach planing speed sooner and because V sections are better planing sections than U sections (when did you last see a planing powerboat that was not V sectioned) the boat should stay on the plane longer.
There are other advantages too numerous to list here but include being able to fully raise the centreboard on the run, with a consequent reduction in drag, and having more grip when stalled before the start which enables more room to be made to leeward.
The shape is a culmination of many years of development and has also been used on my aptly named International 14 'Departure', which has achieved considerable success, and also on my One Metre 'Arrival' amongst a number of successful designs all of which have proved fast.
So, with these two completely eclectic new boats on the stand this weekend at the RYA Dinghy Show, why not drop by and see the vast range of options available to suit all pockets for those who just love to sail a delightfully responsive and rewarding dinghy.