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Merlin Rocket Design Guide

Part 3 - Older designs

Rewritten in 2007 by Chris Martin
The boats listed in this section are most likely to be seen racing at clubs on reservoirs inland. None are less than 15 years old, and although they form the backbone of the class, they are unlikely to have been further afield than the local circuits, where they still have their day, especially if equipped with a modern rig.

They make an excellent, low cost, introduction to the class. Prices start at around £500, though many potential restoration projects go for much less.

Greg Gregory Designs

Both Gregory designs were radical departures from established design principles. Each was quite unlike anything that had gone before. The Ghost Rider is one of the most successful designs of the seventies.

Ghost Rider (1970)

Very stable, excellent boats for lightweights, especially in heavy weather. Slow to tack, so not ideal for river sailing, and perhaps reluctant to plane in marginal conditions. V-sectioned with less rocker forward than earlier designs. Beam 6'10" (2.09m), and suitable for up to 22 stone. There are some modified versions of this design. Ghost Riders won the Silver Tiller in 1972 and 1976, the Inlands in 1973 and 1976, and the Nationals at Plymouth in 1971. Other Championship results include 5th 1970, 6th 1971, 2nd 1972 and 6th 1973. Ghost Riders have often won restricted water open meetings even in light airs, and they are still a good design for the under 20 stone teams. Very popular in the early 70's.

Echo (1973)

Round-sectioned development of the Ghost Rider with full, shallow entry, and narrow rounded transom. On smooth water, this design shares the characteristics of Ghost Rider but slams badly to windward against a short chop and is therefore not a good sea boat. A full bow is not usually associated with nose-diving tendencies, but in the case of the Echo, the extra resistance when the nose goes down apparently makes the boat difficult to control in strong winds, especially in waves.

Keith Callaghan Designs

Keith Callaghan's designs are now only really suitable for restricted water. Keith's philosophy was that upwind performance was vital to get away from the start at sea and from other boats inland. Their reputation for needing careful handling downwind is perhaps only partially justified.

The early designs, especially Hotspur, have a high initial stability, which can lull the inexperienced into a false sense of security on the run. A wave, a windshift or carelessness in bearing off can cause a death roll before the helm wakes up. Apart from this possibility, the early designs are quite easy to sail.

From Hexagon on, Keith's designs became less susceptible to the death roll. However, they have less initial stability, which means that more precise handling is required if they are to win races.

All Keith's popular designs were fast boats, and very rewarding to sail. All except Hebron and perhaps Hazard, are responsive and quick-tacking in light airs. Hotspur and Hornblower were built by a wide range of amateur and professional builders. Many are excellent, but beware of poor construction.

Hebron 1966

Very stable and good in a blow, but sluggish in light airs. The first Merlin to reach a beam of 6'6" (1.98m). Only one was built. Suitable for less than 20 stone.

Hotspur 1968

Development of Hebron, with finer ends. Excellent river boat. Beam 6'3" to 6'5". Suitable for about 23 stone.

Hornblower (1970)

Designed as a maximum beam development of Hotspur, with narrower waterlines. The original Hornblower was wider than boats subsequently built to the same underwater shape. Good in a blow, slow in light airs. Beam 6'9" (2.06m) except the prototype. Suitable for up to about 23 stone. 4th in the 1972 Championships and 2nd in the 1972 Silver Tiller.

Fourunner (1973)

An experimental 4-plank Hornblower. The only 4-plank construction Merlin Rocket, requested as an experiment by the class committee. It did not take on.

Hexagon (1973)

Development of the Hornblower for improved light weather performance. Very fast in expert hands. Beam 6'10" (2.08m). There is a maximum beam variant which is also very fast (e.g. 4th in the 1973 Inlands) but which is said to be difficult to handle offwind. Hexagon is suitable for up to about 24 stone. Winner of the Silver Tiller in 1973 and 1974, and second in 1973, and second and third in the 1974 Championships.

Hysteria (1974)

Development of the Hexagon with reduced keel rocker aft, and softer bilges. Very fast all round, in expert hands, with a further improvement in offwind handling. Suitable for up to 24 stone. 4th and 6th in the 1974 Championships and 6th in 1975. Callaghan's best - many built by Aln Boatyard.

Hazard (1977)

Development of Hysteria, with reduced keel rocker and more U-section bows. Good in a breeze, but not such a good weight-carrier in light airs. Suitable for up to 22 stone.

Rob Inglis Designs

Rob Inglis took advantage of the technology available in the Naval Architecture Department at University College London. For his second design, Bad Company, he made use of computer visualisation facilities. These enabled him to assess the effects of design changes and crew position on wetted area and stability of the boat in a range of heel and trim states.

Still worth a look on restricted water, but totally outclassed offwind by the newer designs.

Risk (1974)

This boat has a very fine U-section bow merging into a rounded mid-section with a slightly V'd run. There is very little keel rocker forward and the centre of buoyancy is well aft. Risk proved to be very stable and good in a blow, but slow tacking and disappointing in light airs. Beam 6'9" (2.09m).

Bad Company (1977)

A fine V-section bow blends into a rounded mid-section and narrower waterline aft. The shape is somewhat distorted at mid length in order to keep the waterline narrow whilst just satisfying the rise-of-floor measurement. Keel rocker is low. Beam 7'0" (2.13m). Good inland, excellent to windward and carries weight, but hard work in a blow.

Bad Company is suitable for crews up to 28 stone. It is average in both tacking speed and stability. This design won more open meetings than any other in 1979. However, the design won a race at the Championships at Falmouth and finished 7th overall. Won the Silver Tiller in 1979 and '81, 2nd in 1980.

Still worth a look on restricted water, especially later versions with a low bow tank., but totally outclassed offwind by the newer designs.

Guy Winder Designs

Since building his first two designs for himself, Guy Winder has become one of the leading builders of the Merlin Rocket class. Guy's background as an aircraft engineer show in his quest for precision in building. His designs can be recognised by their characteristic convex sheerline and relatively narrow transoms, although these features are less marked on his later designs. His home waters at Hollingworth Lake made him lean towards boats which would perform well on lakes.

These boats accelerate quickly and some helmsmen have unexpectedly slid downhill along the sidedeck and over the transom into the water! Their crews report that this is somewhat disconcerting. Recently Guy and son David have concentrated on building boats to variations on the Canterbury Tales shape – see the ‘modern’ section earlier on in this document.

Wideguy (1973)

Based on the September Girl design and modified for a beam of 7'0" (2.13m). Extreme convex sheer. This boat proved to be very fast carrying about 20 stone.

Late Night Extra (1974)

This boat differs from Wideguy in having a finer entry, less wetted area, and the centre of buoyancy further aft. The chine is more pronounced and the transom deepened slightly but reduced in width. This boat finished 5th in the Inlands twice in 1974 and 1975. Beam 7'1".

Winderbox (1975)

Development of Late Night Extra with increased beam aft, deeper hull and stem, and the chine reduced again. Beam 7'1". Very fast in all conditions in expert hands, but difficult to sail well. Suitable for up to 23 stone. There are several variants of this design. One early example won a Championship race at Abersoch in 1978 and seemed to be heading for a place in the first three, but failed to complete the required five races. Winner of the Silver Tiller in 1978, 6th in the Inland Championships in 1976 and 2nd in 1978.

Clasher (1977)

U-sectioned development of the Winderbox for improved sea performance and increased weight carrying ability. Beam increased at the shrouds and reduced aft. Stem deepened and chine softened. Beam 7'0", suitable for 21-24 stone. Three were built, 3114, 3132 and 3139.

Disguys (1978)

Further development of Clasher for increased weight carrying ability. Several variants of this design have been built with differing hull depth and beam, and different transom widths. Beam between 6'10" and 7'1". An example of this design won a race in the 1979 Championships at Falmouth and another finished 3rd overall. This design won the Inlands that year and is suitable for light to medium weights.

Stilleto Mark 1 (1980)

This arrowhead-shaped hull was designed to be heeled when sailed upwind and was intended to sail in the direction of the chine from the leeward corner of the transom to the bow. A gybing centreboard was designed-in to align the intended direction of travel. Although Stiletto achieved a few good results it was not the success hoped for. One of the major problems was the amount of wetted area around the transom especially when at sea and this impaired good all-round performance.

Stilleto Mark 3

On two occasions Guy took out the transom and cut darts into the hull, pulling the planks together to reduce the wetted area. He also altered the bow for a finer entry. The gybing centreboard was abandoned and Guy now considers Stilleto's performance to be acceptable for lightweight crews. The boat has had several successes and Guy actually won the last race of the 1984 Championships in this boat.

U-turn (1982)

This is a development of Disguys, with increased beam aft and with the bows made finer above the waterline. The way in which the hull is planked has been revised accentuating the U-section entry. Does well at Oulton Broad.

Uptown Girl (1984)

This design is a modification of the Phil Morrison NSM 2, flared out to maximum beam with a wider transom, flatter rocker and fuller at the ends. Designed to carry more weight, the boat proved very successful with 27 stone on board.

Modified Uptown Girl (1985)

Same as the above but with a narrower waterline for lighter crews.

Phil Morrison Designs

September (1969)

Phil's own first Merlin - home built.

September Girl (1970)

Derived from Phil's very successful China Doll design of a National 12. A quick tacking very good all-rounder for medium weights. Better inland than on the sea. Beam 6'4" (1.93m). Suitable for 23 stone. Very popular from 1972 onwards.

Phantom Kipper (1972)

A wide version of September Girl. Beam around 6'9" (2.06m). Suitable for up to 24 stone. Quick tacking, was a very good all rounder, although there is a tendency to slam in a short chop (September Girl shares this). This design won the 1972 Championships at Falmouth and came fourth in 1973. It is still capable of winning open meetings. Very popular in the North, examples by Aln Boatyard are worth seeking out.

Satisfaction (1972)

Designed for good light weather performance carrying heavyweights. This design achieved its purpose admirably and is an excellent choice for heavyweight crews, especially inland. Said to be hard work to windward when sailed by lightweights. Beam 6'3" (1.9m). Suitable for about 26 stone.

Smokers Satisfaction and Fadeaway (1974)

The Smokers Satisfaction is a flared-out version of the previously successful Satisfaction, designed to carry more weight. This design is probably the most famous all-rounder and certainly one of the most successful designs ever (there were 101 built). It has proved successful at all levels with a variety of crew weights, and is still going strong today. A variant of this design is the Fadeaway.

It is noted for being a good all rounder, and is a reasonably fast tacker. It is good in light airs and was certainly the most successful design of the late seventies. It won the Championships in 1975, 1977 and 1980, and won the Inlands in 1974 and 1977 (Fadeaway won in 1974). The design still wins open meetings and many club races, and as an example of the design's durability came 22nd and 24th in two of the 1987 Championship races with 24 stone on board (fleet of 88, medium wind)

Infidel (1974)

A very good open water boat for lightweights. Extremely stable, but very slow tacking, and so unsuitable for restricted water. Beam 6'10" (2.09m). Suitable for under 20 stone.

Several varieties of this design exist, with improved weight carrying ability and light weight performance, merging into the Hooligan design. The best known variant is the W.T. Special Infidel which finished 4th & 5th in the 1974 championships, 5th in 1975 and 10th in 1979.

Hooligan (1975)

A development of the Infidel for improved weight-carrying ability and light weather performance. Still rather slow tacking and sluggish in light airs. Suitable for up to 22 stone.

Mustard Seed (1976)

An experiment with a 'gull wing' underwater shape for reduced waterline beam and low wetted area. Still has the occasional open meeting success, but did not achieve popularity. 2nd at Whitstable Championships in 1976. Another lightweight's reaching machine.

Super Seed (1976)

Mustard Seed with extra curve in the run to give more buoyancy for heavier crews.

Summer Wine (1977)

This design was an extreme one in its day. With a fine U-section bow and flat aft sections it is very fast reaching in strong winds but has been noted for its nose-diving tendencies when hit by a sudden gust (sit on the transom or sink!).

This design was initially popular and then went out of fashion when the NSM2 came along. Then in the early eighties it had a big revival, especially with lighter weight crews. Probably superseded by the more recent developments along this theme, the Summer Wine is likely to be slightly less expensive than the boats mentioned above and a good example could prove a bargain.

NSM1 (1978)

This design was in concept somewhere between the Smokers Satisfaction and the Summer Wine. Essentially the Smokers was well known for its ability to carry weight, and the Summer Wine was a design for lightweights. The Wine's classy performance caused the well-built fraternity to pester Phil Morrison for a Wine that would carry weight. NSM stands for “New Smoking Material”.

This boat was an instant success when introduced in 1978, and soon became the most popular design, particularly after the GRP version appeared in 1980, some 35 being built. The NSM2 derivative quickly replaced it in the early eighties and it must be said too, that the rig was evolving rapidly at this time, and since 1980 boats have had a low bow tank which gives more hull stiffness to cope with the increasing loads placed upon it by the modern rigs.

The NSM's stability makes it suitable for those regularly racing in strong winds or those converting from more stable boats such as GP14's who find other Merlin designs a bit tippy.

NSM2 (1980)

The NSM2 is the design most people think of as a first Merlin for someone sailing inland. The design is a development of the NSM1 with fuller sections under the mast and in the bilge near the stern to carry more weight (around 24-26 stone).

There are also two variants: Guy Winder modified the design to produce Uptown Girl (3338) which was filled out even more under the mast to carry more weight, and Jon Turner has produced a Seventh Heaven version which is slightly wider, has a slightly flatter rocker and a slightly flatter transom. Quite a few have been built in FRP, though the wooden ones tend to be preferred, especially examples by Rowsell’s and Jon Turner.

The NSM 2 can be summed up as an extremely good all rounder, many were built and are still being built. Can potentially still do well at Silver Tiller meetings on restricted water – 3353 won an Silver Tiller meeting on the Thames in 2006!

Gnome and New Potato

The Gnome is definitely a boat for the lightweights, excellent on open water - preferably a sea with a moderate chop. It is a development of the New Potato and is a real flyer on the reaches. Only two New Potatoes have been built, but it won the Silver Tiller in 1984, was second in the 1982 Championships, and 3rd in 1983. However, while the flatter hull planes faster, it does make the boat less versatile than the NSMs which are perhaps better across all conditions. The history of the design can be traced back to the Summer Wine and indeed the rocker is exactly the same. Relatively few have been built, but again in the right hands and with a modern rig it could still be fast at ST meetings.

NSM3 (1983)

An NSM2 variant designed to carry a little more weight with slightly increased rocker in the run, and slightly fuller sections from the mast to the transom. Only two boats have been built to the design 3327 & 3340. Black Adder came 2nd in the 1983 Championships.

NSM4 (1984)

A popular design in the late 1980's, this boat is a development of the NSM family and has moved the NSM concept closer to the Summer Wine. This means that the boat is very flat, quick to plane, very wide to give extra power and is aimed at an all-up weight of around 22-24 stones. The design is basically an NSM2 flared out above the waterline, with slightly flatter forward underwater sections. There are many examples of NSM4s on the water. The minor variations produced by builder's tolerances and interpretations are alleged to significantly influence performance.

What is a White Whale?

This is an NSM4 built by Rowsell and Morrison which has spray-painted decks and insides, instead of the usual varnish. The subsequent reduction in man-hours required to finish the boat have enabled this version of the NSM4 to be produced more cheaply than a conventional Merlin. Although these boats were successful on the water only four were built, owners preferring to pay a bit more for a beautiful wood finish.

Design 42 (1990)

Underwater sections are closest to the NSM2, whilst above the water the greater sitting-out power of the NSM4 is retained. The design name apparently comes from The Hitch Hikers Guide to the Galaxy! Deep Thought and Roaring Forties have been built to this design.

Early Ian Holt designs

Ian Holt started his Merlin design process with a clean sheet and an open mind. His very early boats are a little unconventional, but most were still fast. Relatively few of these boats have been built, and they tended to be specific either to Ian himself or the client who ordered it.

Nice Legs

Rudely described as a cross between a Ford Sierra and an aircraft carrier, this boat was a complete break from the current fashions in the fleet. Very full in the bow, high freeboard and a huge foredeck created by having the maximum beam well forward where the crew sits, finished off with a bustle in the run aft. All this had the rest of the fleet scratching their heads in disbelief. This was not helped by having a large radiused traveller on the foredeck for a self-tacking jib. Initially slow, the boat became gradually faster throughout its life and had a good championship at Whitstable in 1989 in the hands of its builder, Guy Winder, six years after its launch. Like most of Ian's designs, it did better in strong winds.

Once Bitten

The lessons learnt with Nice Legs resulted in Once Bitten, at the time the most extreme hull shape being built. Characteristic of Ian's designs have been the very flat forefoot, a hard shoulder just above the waterline near the midships section, and a chine in the run aft. These were retained, but reduced slightly compared to the original design, and the bustle significantly reduced in the run aft. Sold within a few months of being built to Alan Warren, this boat came 6th, 3rd and 3rd again in the 1986, '87 and '89 Nationals respectively.

Diamond Smiles

There have been two near sister-ships to Once Bitten, both taken off the same frames. The first is Diamond Smiles, designed over a telephone conversation between Norway and Bradford, when Ian Holt was working over-seas. The only differences between Once Bitten and Diamond Smiles are an increase in the rocker both just behind the bow section and in front of the transom, in an attempt to carry weight slightly more successfully. This boat finished 6th overall at the 1985 Championship and won a race at the Championship in 1987 - the first Holt design to do so and the first sign of a threat to the Morrison monopoly.

Niane

Holt was convinced that he still had not found the solution to the heavyweight's problem, and further talks with Jackson in 1989 led to a new design for 1990. Based on Canterbury Tales, this design has a fuller stern and slightly deeper midships section.

Dangerbat

Dangerbat was commissioned by Dick Batt for 1987, having watched the performances of Once Bitten and Diamond Smiles in the previous seasons. Dick wanted to take the design concept to its logical extreme and went to Guy Winder with a number of modifications. The most significant was to straighten out the run aft to eliminate any hint of a bustle. Another move, more obvious but of less significance, was to incorporate a rounded transom, removing some weight in the stern of the boat. This boat, after being sailed with slightly too much weight on board for its first season, finished tenth at the 1988 Nationals before winning the championship in ‘89, proving devastatingly fast both upwind and down with the correct crew weight on board. Definitely not a boat for heavyweights!

Riders on the Storm

Riders on the Storm was the first boat to be commissioned from Holt, and was a result of discussions at the 1985 Championship when a heavyweights' answer to the NSM4 was being sought. It was further development of the Once Bitten/Diamond Smiles concept, but an attempt to find more buoyancy somewhere in the underwater sections without losing what was considered to be an extremely fast and powerful planing hull design.

Who's a Pretty Boy

Simultaneous to the design work being carried out on Riders, a South-East version of this idea was being put together with Alan Jackson, aimed at the pond sailor and Salcombe Week. This design won a race at Salcombe, but thereafter never received the time and effort to assess the potential of the boat. The changes were basically to tuck in the transom to help tacking and carry heavier helmsmen. Soon on the heels of WAPB - in fact off the same frames - came Heap Big Rudder, so named because the designer’s last notes to the builder were to stick a very large rudder on the back of all these boats (having watched Warren capsize countless times in Once Bitten during the windy 1985 Championship). This was simply WAPB with the transom dropped half an inch to reduce the bustle at the rear end. This lengthens the waterline for speed in sub-planing winds but needs a lighter helmsman.

Riders on the Storm 2

Otherwise known as Buckle Up, this was a modified version of ROTS1, incorporating the owners' ideas for the next season. On the water for 1988, this boat is possibly the best of the Holt breed for the heavyweights, and won the Silver Tiller in 1988. This was followed up with second place at the Inlands in 1989, 4th overall at the '89 Nationals, and another overall victory in the Silver Tiller. Guy Winder and Ron Hall built the few examples ordered, they should still compete with a Canturbury Tales if armed with a decent rig, but this is hard to substantiate as none have been seen on the circuit for over 5 years.


See also:
    Part 1 - Introduction
    Part 2 - Modern Merlins
    Part 4 - Glossary