27 years of Half Ton designs

THE EVOLUTION OF OUR HALF TON DESIGNS FROM 1966 to 1993.

I have been fortunate to have had the opportunity to design yachts aimed at the Half Ton rating limit from the very beginning to the very end of the Half Ton era, but until now I have never looked back at this collection of designs to see what they have in  common, other than being Half Tonners.
Many of my fellow IOR designers have had tremendous successes in this sphere of design and some, having produced winning boats, have adopted a theme and/or strategy of steady development in their ongoing work.

Looking at my own efforts now, through the prism of reflection, I wonder if my apparent scattergun approach to a supposedly ‘level’ problem was the right one. This journey of trying to remember the why’s and wherefore’s of design processes has been a head scratching time. I hope you enjoy my ‘logic’, as best I can remember it!
A key driver of any race boat design project, however, is – ‘just how much of a race boat is it going to be’? If the answer is pure, no holds barred race machine, then the answer to that question is clinical and simply comes down to the designers interpretation of the rule and the expected conditions of the primary event. If however the design is to be coloured by a dual purpose role and or fulfilment of production building techniques, the answer is anything but clinically pure.

Some of these 14 designs of mine, covering 27 years, fall into the pure race boat slot while others are heavily influenced by a dual purpose requirement. There is a third category too – which is the ‘I don’t give a damn about the rule – let’s just design a fast boat’.

REVERSE is our 1966 offering. Designed to the RORC rule she is pure racer. Totally inspired by Illingworth and Primrose with a little van de Stadt thrown in on the spade rudder department. I was surprised, looking back, just how narrow the design is and by the choice of wheel steering at the front of the cockpit- Outlaw style.

Our next design, the Banham 29, drawn in early 1970 is our first attempt to interpret the brand new IOR. But being a grp production design she is ultra conservative. A moderately heavy, short waterline boat with a big rig, the builders required a dual purpose boat with good accommodation. We managed to keep weight out of the bow, however, with an empty fore peak. Slightly against expectations, this design performed best in a breeze – probably due to a big lead keel, very firm sections and a wide waterline.

And then in 1971 came Strawberry Fields. A very different beast altogether from which three further designs were derived in quick succession. Strawberry Fields was the epitome of a racing machine. Completely empty from the mast forward, she had tubular alloy pipe cots set as far aft as possible, a minimal galley, a bucket for a toilet and no floorboards. To get down below you dropped through a hatch in the bridgedeck. There was no companionway hatch or steps or even fore hatch. All too heavy. Storage below was exclusively courtesy of store bought plastic bins!

I poured over the, still new, IOR rule book for hours developing her lines and came up with, what I believed at the time, was a unique double hull form aft of the keel extending aft almost to the transom. It was designed to have the same effect as the bustle developed by Sparkman  &Stephens, but instead of being faired in with distorted buttock lines it was more canoe shape grafted onto the bottom of a shallow main hull. It’s main purpose, however, was to get displacement aft and to trick the measurement rules into thinking the boat had a shorter sailing length than it actually did. The effective ‘measured’ length equated to a waterline of 23ft, but in reality the hull extended nearly two feet further aft. This together with a very wide full stern gave the design a very long sailing length albeit married to a short overall length. The bow is ultra fine with max beam well aft. In order to extract the most out of the measurement points we adopted a chine amidships combined with an almost bizarrely narrow waterline. After the plug was constructed, rule changes made to IOR cost us dearly in regard to the chine and the ultra narrow waterline, so when she was launched in early ‘72, we had to slice a fair amount of sail area out of the genoas. She did prove to be an excellent heavy air boat, but certainly lacked upwind and downwind area for light airs.

After the rule changes hit us so hard we did a follow up boat, No Expectations, and addressed the chine ‘ penalty’ by running it right aft to the transom. That technically made it a hard chine boat so we could keep the beam measurement right to the edge of the chine. There was nothing we could do however about the waterline beam problem, but we did extend the waterline back even further by bringing the rudder up from underneath the bustle to behind it. It seemed to work pretty well, but as is so often the case the two boats never sailed against each other. In fact that is a historical element of this entire half ton development. I know of no situation where any of these designs have sailed against each other!

Helier Skelter in ‘73 was arguably more rule friendly. We gave up on the chines and narrow waterline, but kept the superfine entry, full stern and beam aft shape. The bustle became a bit more conventional and the displacement went up considerably so we could gain some sail area. It was our first foray into fractional rigs too seeing that you could gain ‘free’ sail area under the rule. Once again she was completely stripped out and the high freeboard allowed the deck to be almost flat with no coach roof.

Strawberry Dragon was essentially similar, but with a fully fitted interior, coach roof and displacement increase to match. We also pinched in the stern a little bit for reasons I cannot remember! Later in life this boat cruised half way around the world and now lives in Australia.

In 1976 we drew the Eliminator 32 for E Boat builders Production Yachts. Hull wise the Eliminator was created to get everything out of the fast changing IOR, but in reality when you give a high volume hull to a production boatyard they want you to fill it with interior. We tried all the tricks to get the best of both worlds with all the primary berths aft and the galley, chart table and engine forward, but it all still weighed a lot and virtually all the owners plumped for the fully lined interiors and Treadmaster on the deck. Rating this dual purpose cruiser/ racer configuration fairly was where IOR really fell apart. The fitted out boat weighed 20 per cent more than the designed stripped boat and yet the rating was higher!  It was impossible to explain this ‘logic’ to the bewildered owners. The fitted out Eliminator’s did eventually have their glory days, but not until the advent of CHS and IRC. Our choice of extreme fractional rig with giant mainsail and very short foot headsails didn’t help either – particularly as we elected for an ultra simple single spreader, runner free, swept back rig. The sailmakers and sailors were struggling to get the best out of the set up for upwind performance. Team Sails got the hang of it though taking an Eliminator to an overall win in the Tomatin Trophy.

We also pushed the rule hard in the hull shape department with billiard table flat sections running from stem to stern, lots of beam, narrow waterline, wide, flat  stern sections and only minimal distortions around the aft girths. Under IOR the design really came into its own when stripped out below and fitted with a no compromise rig complete with runners, checkstays and in-line shrouds.

The design was further developed in 1979 with Existential using the hull and deck mouldings from the Eliminator, but extending the stern to give a truly massive overall length of 34ft. Needless to say this ‘freebie’ only survived for two season of IOR racing. In common with the Eliminator the forward waterlines are completely straight giving a fine entry.

Our first ‘non-rule’ Half Tonner was Eagle in 1978. This was a deliberate attempt to take the Eliminator concept , but take out the rule inspired flats. We made the bow even finer and veed and the stern as full as possible. To ‘pay’ for this in IOR terms we went for virtually no overhang at the stern and a transom hung rudder. Once again a fractional swept back spreader rig was employed. This basic design went on to be very adaptable with daggerboard, lifting keel, long keel and even winged bilge keels. As an IOR Half Tonner I don’t think the theory was ever tested. Looking back now the design philosophy had much in common with the S&S designed Columbine of 1972. I suppose this is how influences creep into designs.

Probably our biggest rule pushing Half Tonner was the 1980 Extrovert 33. Intended as an aluminium semi production boat, a couple were also built in plywood. The multi chine shape is perfect for exploiting the measurement points in IOR and we pushed the measurement points around the stern with a big crease that we had used very successfully on the mini ton Silver Dream Racer.

In 1980 we also developed the Grace design for an Italian builder, but this was very different again as part of the brief was to make the design road legal for towing so the beam was limited to 2.5 metres. Also required by the builders was a fitted out interior and lifting keel and rudder. This concept was quite a challenge and in order to help it rate Half Ton we looked once again at the double hull design  aft ( previously seen on No Expectations in ‘72)  to give maximum sailing length with minimum measured length. As the boat is light, long and narrow, the rig is necessarily small, but effective.

The North 26 (actually just under 27ft long) was drawn in 1981 with only half an eye on the rule. She was to be ultra light, ultra fair and capable of planning. We just made sure the IOR measurement points fell on the chines and pretty much left everything else to take care of itself. As an IOR racer it pretty much proved that a boat like this can win, but it’s impossible to make an all rounder IOR boat without exploiting all of the idiosyncrasies of the rule.

Next up in 1982 was our Half Tonner for racing on the Arabian Gulf – hence the name – Gulf 30. This is unashamedly a light air design. Light displacement, short waterline and big rig. The high cg keel is to help with weight concentration necessary in the ‘sloppy’ seas of the region. For good performance in a breeze the stern is full, but in this design it is balanced with a fuller bow to help reaching and running speed.

In 1985 came Lightning – basically a development of our Eliminator design which we still felt had plenty of potential. The main differences in the design were in the bow area where the sections were much softer.

Our final tilt at an IOR Half Tonner came right at the end of the IOR era in 1993 with Platinum. It was slightly tongue in cheek as the owner’s primary interest was to race JOG and this series had, by then, gone over to CHS. We decided to make the key points of the design work as a CHS racer, but to keep the overall package within certain IOR parameters. This meant, for example, employing a small bow overhang – upright bows rate very badly under IOR, a combined fractional (for IOR) and masthead ( for CHS) rig and interchangeable keels – one low cg and one shallow IOR keel.

And so the journey came to an end with the demise of IOR in 1994. I hope you have enjoyed this summary. It made me realise that there was potentially so much more ‘story’ per boat, but that will have to be for another time! I hope the drawings I have selected make sense with the words!

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