UK-Cherub Class

Get Your Heart Racing


Around the 1972 Cherub World Championships

This article was first published in “Sea Spray” Magazine, New Zealand with comments in italics from Jim Champ

The recent Cherub World Championship in Auckland provided a great opportunity to study and compare trends in the class. For a restricted class with a one design sail plan and only limited scope for hull design it was amazing the differences in design, rig and gear, of the boats from different countries and even within countries themselves. Because of big differences in design Cherubs are still rather a “horses for Courses” class. This year's championship proved to be a contest for the “Flatties”.

Top New Zealand Boats (St. Paul [sailed by Steve Marten, now head of Marten Marine, one of the top international high-tech boatbuilders - Net Ed.], Boss-O-Nova) were modified versions of Angel Gabriel and Jennifer Julian designs. Both had about 1/2 inch less keel rocker and chines were also flattened out to run parallel (in elevation) with it, thus having a longer, straighter planing surface. In this respect we seem to be following Australian designs - although our boats still differ from theirs in having curved bottoms, more vee in the bottom at the stern, and more curved gunwales.

Most New Zealand boats racing in the championships were Angel Gabriels (Marten) (13) Whirlydogs (6) Jennifer Julians [designed by Russell Bowler, now of Farr Yacht Design] (4) or Farrs (3) [designed by Bruce Farr of course]. Older boats with more keel rocker (“banana boats”) such as Spencer MkVII or VIII have definitely been superseded by newer designs, indeed there was only one of each of these boats racing.

With large numbers of Cherubs sailing in Australia there are many designs, mostly by professional designers. Of the 12 Australian boats at the Championship, 10 were different designs. However, they were all designed with one aim in mind, to plane early, so they had some similarities. Keel rocker on all boats was very flat from centrecase to stern. All had big transoms by NZ Standards, average chine width here was 3ft 6in with less bottom vee, generally about 3in. Most boats had flat bottoms, with chines kept parallel to keel (in elevation) and each other (in plan). Because of the big sterns, gunwales were fairly parallel, making them big boats.

Ikara was top Aussie competitor finishing 3rd overall. She was designed by her crew Greg Phillips and John Gardner in a rather unorthodox fashion. Their theory was that straight boats are fastest, hence a straight keel and chines in both elevation and plan. A constant and moderate vee was necessary for both downwind speed and control Finally the shortest distance between two points is a straight line thus the flat bottom and plumb topsides to clear the water from the hull quickly and reduce wetted surface. Fourth overall was Zulu II, built by Dave Frazer to his latest design, the main features being the extremely flat keel (2in rocker) and the very full cone shaped bow. Marc VI in sixth place was a two-year old Maurach design, very similar to Ikara. Rock'n'Roll, 12th overall and sister ship Boogie-Woogie, were designed by the boat's builder Ian Peden. Their most notable feature was their fine JJ type bows, not often seen on Australian Boats.

Fourteenth overall and first woman skipper was Jeanine Wilmot [Jeanine was later NZ Javelin South Pacific Champion and is now married to Australia 2 Navigator Hugh Trehearne] in Emu, a sistership to her brother Jamie's boat Jazzer (runner up in the first world Championship). Jazzer was a Ken Beashel (former World 18footer Champion[and later to be chief maintenance man on Australia 2 at the 1983 Americas Cup - Net Ed.], designed and built boat, of rather unusual design. She had a fine bow, with low chines disappearing about 12in back from it. The keel was almost straight from centrecase to stern but had a lot of rocker from the centrecase to the bow. In plan view the chines were more pushed out in the middle than most Australian designs. Another unusual feature was the foredeck which had about 8in of camber under the mast step effectively raising the whole rig 4in.

The two English entries were outclassed. I got the impression that the class there lags well behind in development. Of the two, Jamstrangler sailed by her owner and builder Chris Forman was the most successful finishing 30th overall. She was a conventional boat, designed for easy amateur construction, with her U section bow, straight run aft and moderate vee stern sections. The centrecase was designed to allow the centreplate to slide under the foredeck. [Presumably a Forman 4 - Net Ed..] The other boat, Amphigouri, sailed by Mr and Mrs David Babcock, finished 36th overall. This boat was the most unusual looking at the contest. Being a strictly light weather design, she had a lot (6in) of rocker in the keel, a flat bottom of moderate vee, a very fine bow with gunwales pushed out to 5ft 3in where the skipper sat and pulled in sharply to the small stern. This boat also had a full length centrecase with a pivoting centreplate. [Greg 5 I suspect - Net Ed..]

Performance

It's hard to say what affects the performance of a Cherub most. My opinion is that rig, design (provided its a new one) and skipper are the main factors affecting speed. It was unfortunate that conditions for most of the Championship remained the same, a moderate to fresh sou'westerly and smooth seas. However, the second race was sailed in a light to moderate sou'westerly and it was amazing the way these conditions affected some boats. Flat water and moderate to fresh winds ideally suited the flatter keeled New Zealand boats (St Paul, Boss-O-Nova) and the new Frazer and Marauch hulls (Zulu II, Marc VI, Ikara, Bizarre) whereas those with more than average keel rocker (Omega, Underdog) fared poorly.

The lighter wind in the second race showed some surprising reversals of form. Boats with more than average keel rocker did well, finishing a lot higher than their average placings, e.g. Omega (2) Underdog (11) Amphigouri (10). These conditions definitely didn't suit the Frazer and Marauch boats e.g. Zulu II (31), Bedazzled (38) and Bizarre (36). Although a flat keeled boat, Boss-O-Nova, won. Outstanding boats in these conditions were Boogie-Woogie and Rock'n'Roll. In the invitation race and abandoned first race, held in similar light conditions, they finished first and second respectively both times. In the second race Grant Simmer finished third, while Karen Simmer, who was leading until her crew fell overboard, was disqualified from fourth place [Net Ed. - Grant was navigator on Australia 2 when they won the America's Cup in 1983]. It would have been interesting to see how the big full-bowed, flat bottomed Australian boats handled a choppy sea. I suspect they would have slammed a lot to windward, while downwind they have a reputation for nosediving. New Zealand boats of the AG, JJ and WD designs generally proved to be good all round performers, but Australian boats were faster when they got their preferred conditions. It would seem that in flat water at least, the flatter your keel and fresher the wind, the faster you go, however if the wind doesn't blow you don't go. [Net Ed. - And ain't that the truth!]

Construction and Layout

New Zealand Boats had nothing new to offer in construction and layout. Most were built with a double skin bottom over either one or two stringers aside the keel. The rest were built with single skin bottoms over three stringers aside the keel. Layout was universally the same, all boats had a full height bulkhead 4ft from the stem which encloses the forward buoyancy tank. From this side tanks of varying widths (minimum 6ins) ran aft to the stern. Rolled side tanks are here to stay, most new boats sported them.

Australian ply boats were all built with single skin bottoms over three stringers aside the keel. The layouts varied a lot probably because most were professionally built by different boatbuilders as the four amateur built boats had the same layout as the New Zealanders.

Of the other five ply boats three were built by Dave Frazer. Drumbeat, a four-year old boat, besides the usual bow and side tanks, had am 18in long stern tank. The other two, Zulu and Bedazzled were this season's model and featured a convex false floor, the height of the centrecase top in the middle, sloping down to the chines, and running from the stem back to central sheeting. Side buoyancy tanks ran from here to the stern. Rock'n'Roll had a full height bow tank, wide side tanks, a 2ft long stern tank, and a floor tank running from the bulkhead along the centrecase top to the back of it. All these buoyancy tanks made the cockpit very small.

Three Australian boats were fibreglass. Revolution was first of the Dennis Digham (12-footer fame) production line and only boat on minimum weight (110lb). It was beautifully moulded with a clean interior and conventional bow and side tank layout. However, because of the lack of stringers and frames (it even had an open transom) the hull tended to bend and twist a bit.

The other two boats were moulded by Jamie Wilmot[Australian FD helm at the 1984 Olympics]. Emu was from a mould taken of Jazzer, while Hello Goodbye was a deeper veed version designed by Jamie. Both layouts featured convex false floors to the aft end of the centrecase, with side tanks form there to the stern, and a small stern tank. Decks and mainsheet traveller frame were ply but hulls were stiff and strong although HG weighed around 145lb. Amphigouri was a fibreglass shell with ply decks, side tank and bulkhead. Her layout was conventional except here foretank was only half height. Jamstrangler was a single skin ply boat also with half height fore tank and side tank layout. Construction method used was rather different and for ease of amateur construction was built upside down from decks up. [This would be Chris Forman's inside out method for building the Forman 4. Roughly speaking you started with bulkheads and tank sides, all nice easy bits of straight wood, which meant that the boat was almost its own building jig.] Because of light hull weight, builders are always looking for ways to lighten the hull but retain strength. The general trend is to use, more and more, materials with good strength to weight ratio. Hence ply is getting thinner (1/8in), and lighter and more use is being made of fibreglass, aluminium and stainless steel to replace wooden structural members (e.g. mast post, centrecase bracing, mainsheet traveller, transom bracing etc.

[Its fascinating to note that no mention is made of whether any of the fibreglass boats were of cored construction. Russell Bowlers' 1970 Worlds winning boat had been foam cored, and he had built a foam boat in England in 1971 with a U.K. Sailor. On the other hand I am quite sure Amphigouri would have been solid glass. Even in 1975 when I started sailing Cherubs the significance of the fact that Bowler's boat had been foam cored was quite lost on many of us, and I can remember being quite bemused about what lumps of foam embedded in the bottom of a new glass Forman 4 were supposed to achieve. At least I wasn't the only one to miss the significance!]

Mark Paterson's new boat QSJB [I now own this boat! Net Ed.] (launched a month before the contest) might have been the first to feature a new trend in the search for lighter weight. His boat had no side buoyancy tanks from for'ard bulkhead aft to the mainsheet traveller. This idea has several merits; less weight, can't leak and trap water, fittings can be positioned under the deck, more cockpit space, and easier to right after a capsize. One disadvantage is that a lot more water is trapped when the boat is righted after a capsize. However competition is now so good that if you capsize you're out of the running anyhow.

[All this talk of minimum weight seems to completely miss the point that the layout of the time was pretty poor at resisting rig loads. It wasn't until about six or seven years later that people realised that if you positioned the front bulkhead so that it ran from under the mast step diagonally back to the shrouds then the bulkhead was far more effective at resisting rig loads. When I sailed the (admittedly by then very elderly) QSJB I could reckon to sail in with quite a lot less rig tension than I launched with. Net Ed.]

Gear

Nothing really new was seen gear-wide. However, there were some interesting variations and ideas. Cherubs are now being set up like miniature Flying Dutchmen, this is particularly true of New Zealand boats, most of which had some or all of their adjustments leading back to the skipper's hand. The most common adjustments were jib cunningham[now there's a bit of string that seems to have died out! - Net Ed], mainsail cunningham, kicking strap, mainsail outhaul and mainsail traveller. Australian boats had the same control, but positioned them at various places on the hull and spars, sometimes well out of the skipper's reach. The English boats lacked most sail adjustments, the kicking strap being about their only one.

Spinnaker launchers have proved to be the biggest revolution in the class since their introduction early last season. All New Zealand boats had them but only five Australians. However by the end of the contest all the others were intending to fit them. Both the English boats had them, but instead of the usual fibreglass chute, they had a triangular hole in the foredeck with a roller attached to the underneath of the back edge.

Jib sheeting arrangements were varies. The two main positions being across the deck or along the carlin. Most used the latter method. A few boats were experimenting with barber haulers but they didn't seem to be an advantage. QSJB had three different jib positions, one inside the other, and when using the inside one could point noticeably higher than the rest of the fleet. [Net Ed - in many ways this is one of the biggest changes I've seen in dinghies over the years. When I started sailing Cherubs jib sheet positions on the older boats were getting on for 6 inches outboard of where they are now!] Over the last few seasons jib sheeting positions have been creeping closer to the centreline.

Central sheeting has become almost universal. Only one boat (Zukes) had end boom sheeting and only two had 3/4 sheeting. Most of the others used free running nylon travellers on tubes or X section aluminium track. Two boats (Ikara, Amphigouri) had no travellers at all, relying on the kicking strap to hold the boom down, using the mainsheet to adjust angle. Boss-O-Nova had a semi-circular I section aluminium track going from gunwale to gunwale which doubled as a kicking strap. [Net Ed - and probably mainsheeting systems is *the* biggest change. The problem with centre sheeting was always that as you pulled the sail in the last few degrees always really dragged the boom down, so letting off the mainsheet just a tad in a gust had a huge effect on the shape of the sail. Sail a Laser and you'll see what I mean. So some bright spark invented the mainsheet traveller, which was a great way of ensuring that the helmsman was never quite sure which string he should pull on! The theory was that when you were going upwind you pulled in the mainsheet until the twist was right (often causing the kicker to go slack) and then adjusted the traveller so the angle was right. There were lots of problems associated with this and tacking, especially as you would normally need to pull the traveller to windward of the centreline to get the boom angle right. This meant that there had to be separate “sheets” each side of the boat, and the leeward one had to be left uncleated, and grabbed in a hurry during the middle of a tack. This was clearly not clever. Harken invented a wonderfully ingenious mainsheet traveller that automatically uncleated the leeward sheet, but none of us could afford them, and the hassle was still too great. I can remember building a *rigid* kicker for my Cherub (with help from Needlespar) in an attempt to get round the sail shape problem, but it was never really practical. Wiser heads eventually came up with the two solutions we use today, the mainsheet hoop (or in Cherubs the post, and the fixed bridle, either at stern or centre. In both cases the idea is that the kicker does all the boom tension control, and the mainsheet just pulls sideways. Its odd that the old style of bridle (again look at a Laser) had been around for years. You'd have thought that people might have picked up on the idea sooner. I believe the first was on a Kiwi 470 in the late 70s. We saw it on Flat Stanley in 1980.]

A fairly new innovation was a cam cleat attached to the last mainsheet block, usually mounted on a bracket attached to the back side of the traveller. This allowed the mainsheet to remain cleated while going about. Trapeze adjusters have also caught on fast, over half the fleet had them. Two types were used, the key-hole type and the Vang type. Rob Martin switched to the latter just before the contest and found them a decided advantage, being quicker and easier to adjust.

Compasses were used by a few boats, the most popular being the Suunto dinghy type. The general opinion was that they weren't necessary. However they do help to pick windshifts. Centreplates come in all shapes and sizes. Generally New Zealand boats had shorter, wider plates, about 12-14 in wide and 4ft 3in to 5ft long. The Australians were narrower and longer, about 10 to 12in wide and 4ft9in to 5ft9in (maximum length) long. A good idea, seen on three NSW boats with small for'ard hands, were their spinnaker sheets led through small Riley ratchet blocks.

Masts

The Baverstock 13/4in diameter mast was most popular (75% used them). Most were rigged with a single set of spreaders which pushed sideways about 1in and forward about 3/4 in. The Glenie brothers (Mrs Tiggywinkle) rigged their 1 3/4 with double spreaders and were the only ones using the mast without a stiffener or mast post. The stiffener was a light gauge, snug fitting aluminium tube running internally from base to just above the spreaders[Net Ed - i.e. sleeved]. The mast post was designed and first used by Don Baverstock. It consists of a short length of very heavy gauge aluminium tube fixed to the keel and extending up through the deck 8in. The mast fits snugly over this, resting on the deck. Graeme Bird's moveable mast post was disallowed by the measurement committee. [Net Ed -need some more explanation here. The rules at the time prohibited any kind of adjustment to the rig while sailing, and also specified deck stepped masts. Lowers and prodders hadn't been invented, so low down mast bend was a major problem. The mast post, rigidly attached to the boat, gave exactly the same stiffening effect as a keel stepped mast held rigidly in a gate at deck level. Always struck me as peculiar to permit that but ban the longer mast. The movable mast post was an even more blatant rule evasion as it meant that it was effectively a two piece keel stepped mast. Rigs were generally much less stiff than they are now, and rig tensions were very much lower. Hounds tended to be lower too.]

Steve Marten rigged St Paul and sister ship Antiquary with 17/8 diameter Aitchison light gauge aluminium masts. Double spreaders were used but during the nationals it was found that the mast was bending too much. To correct this a 6in deck mounted post was fitted and stay tension increased. Two boats used Bowler-type home-made masts. Boss-O-Nova's was a 13/4in diameter three tube one rigged with a single set of diamond stays. On the top was an aluminium crane which held the headboard to eliminate mainsail twist. The gooseneck was fixed and the mast swivelled with the boom. Quasar used a 21/4in Bowler-type with nutcracker spreaders, the mast also swivelled with the boom. Steve Mitchell used a 13/4in Riley mast. His was the only one rigged with both diamond stays and spreaders. Wooden masts have almost vanished - only one boat (Zukes) used one in the contest.

Generally the Australian boats were rigged and tuned for one set of conditions. Chiver masts were popular with WA boats. Ikara used a 2in diameter Moth section, with an external stiffening tube on the bottom 2in. [! surely 2 ft - Net Ed] It was rigged with a single set of fixed spreaders. The other three WA boats used 21/4in diameter sections rigged with single sets of spreaders. NSW boats used de Havilland masts. The Wilmots and Simmers boats used light gauge 2in diameter ones rigged with adjustable limited swing spreaders. [Another technical note. In the 60s spreaders were often hinged at the root so that masts could bend more freely - the spreaders then only stiffened the mast sideways, not fore and aft. Later on limited swing spreaders were used. This meant that the mast was initially unrestricted fore and aft by the spreaders until the movement was used up and then the mast stiffened up. This gave a sort of “dual rate spring” effect. This sort of concept has re-emerged with the pre-bent skiff rigs as used on the 49er, except that now we aim for rigs that are stiff initially and then get bendier! - Net Ed] Emu also had a preventer, a short forestay running from the middle of the foredeck to about 6ft up the front of the mast. It was only used in heavy weather, to stop the mast breaking when running flat off with the kite. [i.e. to stop the mast inverting - Net Ed] The other five NSW boats used 21/8in de Havilland masts with single set of spreaders.

All Australian Masts were on the maximum length of 20ft. Amphigouri used a 2in x 2i/2in section aluminium mast (the same section as Foster) made by Stainless Steel Masts Ltd. It was rigged with a single set of limited swing spreaders.

Jamstrangler used one of the legendary Needlespar masts. It was made up of five lengths of machine tapered aluminium tube of varying thickness and diameter. These were slotted together and glued. A plastic sail track was stretched and pop riveted on the back to tension it and hold it together. The maximum diameter was 13/4 in and although it was tapered top and bottom it was fairly heavy. A single set of limited swing spreaders was used to support it.

Booms

Over the last two or three seasons the use of extruded aluminium mast sections for booms have completely replaced the old wooden ones. Now the extruded sections are losing favour because they bend too much. [There was briefly a fashion in the UK for special bendy booms! - Net Ed]The trend now is toward bigger diameter (31/2 in), lighter stiffer booms. St Paul had a 3in x 13/4 in rectangular section Aitchison boom.

Spinnaker Poles

Again aluminium was most popular although some Australian boats and the two English ones used hollow tapered wooden poles. The 11/4in 16gauge aluminium poles used last season bent too much so this season 11/2in diameter 16gauge aluminium was used. Most New Zealand kite poles were double ended, jaws at each end with either sheeves or ss hooks for spinnaker sheets. Length varied from 8ft3in to the 9ft maximum, with most preferring the latter.

Sails

For a class with a one design sail plan there were some interesting differences in sails. [The use of the phrase one design needs explaining. The Cherub rig sails were restricted with maximum luff, leach and foot measurements, plus three cross widths on the mainsail. Area was not measured. Thus all sails were built to the same basic measurements, and were pretty much the same area and planform, but other details were largely unrestricted. Certainly not what we would regard as one-design these days! - Net Ed] Blue Peter sails were by far the most popular (50% used them) with the New Zealand team. Several boats used Hood sails and several others used Hood spinnakers. Three, including winner St. Paul, used Rudling sails, while Boss-O-Nova used a Nalder main and jib, and a Hood kite.

Cassidy sails were used by most WA boats. On NSW boats Miller and Whitworth sails were most popular but several other makes, including Elvstrom and Freshwater, were also used. Australian sails were about 25% dearer than their NZ counterparts. The sails on English boats were of a lower standard in both design and cut than those of NZ or Australia. Amphigouri used Ace of Clubs sails while Jamstrangler used Anderson Aerosails.

Jibs varied slightly from boat to boat due mainly to personal likes and dislikes of owners and makers. Last season Blue Peter jibs had very large foots and no Cunningham holes, cut leaches were also starting to be used. This season their foots got smaller, cunningham holes were back in and cut leeches were universal. Hood jibs had small foots, cunningham holes, and three jib battens. Cloth weight was heavy, about 5oz. Almost all new Zealand jibs were mitre cut. All Australian jibs had parallel cut panels with hardly any foot on them at all. Emu used a yarn tempered sail cloth one which needed very careful handling and didn't last long. Most Aussie jibs had three battens and none had cut leeches.

Again personal preference was used, mainly regarding mainsail shape and positioning of batten pockets. Most had cunningham holes. Several boats had mitre cut mainsails and a couple made by Blue Peter had cut leeches. Two Australian Boats (Emu and Bedazzled) had loose footed mainsails but they didn't seem an advantage. Amphigouri had a soft (short batten) mainsail which didn't look very fast. Jamstrangler also had a loose-footed main with the top two battens full length and the other four short. New Zealand spinnakers were the biggest. They had big shoulders and foots and were fairly full whereas Australian spinnakers were triangular in shape and had very little foot or shoulder but were also fairly full. Amphigouri's spinnaker was similar to the Australians with slightly bigger shoulders but Jamstrangler's was very small flat and triangular, like a single luff spinnaker.

[The author of this piece is unrecorded. They still hold copyright and I would very much like to identify them and ask their permission for reproduction. I hope this unauthorised reproduction doesn't cause offence - Net Ed]


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