Rustler yacht design explained – an interview with Stephen Jones

British naval architect Stephen Jones is renowned for his ability to design boats that are fast, seaworthy and beautiful in equal measure, which makes him the ideal man to design Rustler’s range of sailing yachts. His approach to design, which he explains below, is probably unique and the results speak for themselves.

Stephen, now 72, started sailing with his father in a converted lifeboat in 1956 and his family owned a string of other yachts with a common theme: from a Tabloid to a Tumlare, they were all remarkably pretty. The first boat he bought himself was a Folkboat and he’s also had a long, varied and successful racing career, sailing a wide range of boats from International 6-Metres to IOR quarter tonners.
His passion for yacht design was ignited was when, around age 11, he was at home with a cold. Stephen’s mum bought him the book Sceptre by Hugh Somerville about the seventeenth America’s cup challenger. He thought “Yes! That’s what I want to do, design boats” and he did. He designed his first yacht in 1972.

Stephen Jones is the designer behind the Rustler 33
Stephen Jones is the designer behind the Rustler 33 (above), Rustler 37, Rustler 42, Rustler 44 and Rustler 57

Stephen has designed a wide range of successful racers and many highly regarded cruising yachts, including the Rustler 33, Rustler 37, Rustler 42, Rustler 44 and Rustler 57. He has also designed Rustler’s forthcoming sailing yacht, the Rustler 46.

What’s the process when you’re designing a Rustler?

Rustler give me a brief to start off with, and I do a proposal drawing which has a sailplan, deck plan, fore and aft cutaway drawings – which is the sort of thing you never see published but they are useful – and a general arrangement plan, usually done at 1:20 scale. On that drawing I usually nail down all the salient points of the general arrangement.

I did the structural design for the R37, which was the last structural design I did for Rustler with laminate weights and so forth. These days, specialists who know and work within the RCD rules do the structural work. The 3D CAD work is also subcontracted out because I draw everything by hand.

For hull lines, my designs are converted by scanning the sections as well as a table of offsets. The 3D team work out a ‘cloud’ of points and it usually fits pretty quickly on the hull. I do a fully offset deck using trigonometry, chord rule, quadratic equations and simultaneous equations and it’s done exactly by calculation. I calculate a deck to the nearest 0.1 of a millimetre or I could work it out to ten decimal places if I had to. From that, the 3D people create a cloud of points, it looks like a plague of locusts actually, if you imagine every locust as a point on the surface of the model. They then create a 3D model. The other way is to scan the sections, then refer to the offsets if needed. Either way, we end up with a 3D computer model and then that’s fired off to be milled. I’m still doing everything by hand: keels, hulls, rudders. Although on a boat like the R33 we were able to use Jefa’s off-the-shelf spade rudders which are absolutely fantastic, perfectly symmetrical and ideal for the boat. For the bigger Rustlers I’ll design the rudder with a skeg, or a half-skeg in the recent boats.

The team at Rustler pretty much stick to the general arrangement that I do for the proposal to build in the factory. They will then do complete joinery drawings – which is fantastically clever stuff, far cleverer than I can do. You can make an interior from a general arrangement drawing from a naval architect, but that would give you a 1960s, 70s or 80s style interior which is perfectly adequate but is not good enough for the modern Rustler customer who wants quality, detail and something beautiful to look at. I don’t do the styling or the detail, I just do the basic layout and the geometry which is adhered to by the specialists. If they start chopping it around, they find it doesn’t fit, and I do make sure things fit.

I do all the sole levels too, these are closely followed. If they stray from them, they could get into a mess. For example, you can’t lower the bunk because it goes out of the hull, or you can’t move the stove as it will hit the hull or won’t gimbal past 10 degrees, that sort of stuff.

What part of the process do you enjoy the most?

The hull lines. They are the starting point for any yacht designer but the deck is hard work. Decks are seriously difficult in fact, and it’s taken me a long time to get to grips with deck saloons rather than your traditional IOR wedge-shaped coachroof with a simple cockpit. Deck saloons in particular, and coming up with a styling that looks nice, is quite difficult. Some people can’t do it and others can. It’s like designing a motor car. Your modern yacht deck has a lot of similar design cues to modern motor cars and there are tricky surfaces with a lot of curves, chamfers, twists and radii.

Drawing the hull lines is the part of the design process that Stephen enjoys most

With proportions too, there is a sweet spot. If you look at some of the BMWs from the early 1980s, there’s too much glass, it’s all top and no bottom. There’s a fundamental relationship between the depth of the windows and the depth of the car body and I think they got it completely wrong. Getting the relationship with the height of coamings, the coachroof sides and the other areas is absolutely critical and the person who can judge the sweet spot the best is the most successful. I’m not saying I am that person, I’m just saying that’s what you have to do.

Some of the older Westerlys, for example, had too much coachroof and not enough freeboard. They hark back to an era when people seemed to be scared of freeboard so they ended up having monstrous coachroofs that looked all wrong. Nowadays, freeboards are dramatically higher and some of the modern designs can look good with low and sleek coachroofs. But some brands have overdosed on freeboard. High freeboard can make it harder to board from low pontoons and dinghies. Some boats get it right. If you look at a Sadler 32, it has a reasonable freeboard and a sleek coachroof and the proportions are bang on, it’s just got a horrible narrow stern which we won’t say any more about.

When you’re designing for Rustler do you do anything differently?

It’s not so much the design that’s different, more the style. Rustler makes a different style of boat which started with the 42 and has continued all the way through. The 37, 57 and 42 are all very much related.

Rustler 42
The Rustler 42 was the boat that defined the modern era of Rustler, and led to the distinctive and elegant look Rustler’s offshore range

The 42 started off with a traditional low coachroof. The corner on the coachroof has a radius with a ledge above it. This has become a bit of a trademark which is reminiscent of the way they used to make the coachroofs of wooden yachts; you’d have a canvas-based top that would be finished with a bead of timber, and then have the straight sides of the coachroof. It works well in GRP and it gives you a line that the eye can follow along the edge and you have the radius above it. The 37 is fundamentally a scaled-down 42, it has proportionally more freeboard than the 42 but the coachroof and cockpit are very similar.

What’s special about the Rustler hull shape?

Sweet lines. Any successful yacht designer makes boats with sweet lines. I also use this thing called a nacelle. It’s a wide fairing in front of, and that runs into, the rudder skeg. It lengthens the lines under the water and my personal opinion is that it adds displacement without extra drag. If you add displacement there, you can take it away from somewhere else. You can shave off, slim up or squeeze the lines elsewhere if you’ve added displacement at the back in the form of this nacelle. Fortunately, no one else uses it, and I’m happy they continue not to.

Rustler 42
The nacelle can be seen on the Rustler 42, forward of the rudder and above the propeller

The nacelle only works on heavy displacement boats, it doesn’t work on light shallow boats – you can’t get the shape in there, only on deep heavy boats can you actually use it to an advantage. It’s not a bustle that terminates abruptly with a kick-up. Sparkman and Stephens did this skeggy sort of thing years ago but they deliberately pushed the lines back then abruptly turned them in at the back which is exactly what I don’t do. The S&S bustle thing was slow, and I’m not quite sure how they got away with it. Olin Stephens was quoted as saying he didn’t care about a boat’s downwind performance, they all go at the same speed, all he cared about is going upwind. He didn’t pursue downwind performance, at least early in his career. He didn’t seem to realise you could get serious extra speed if you pay attention to downwind performance. You go upwind at roughly the same speed as everyone else but when you turn the top mark, if you get it right, you disappear over the horizon.

The R42 is over 20 years old, is there anything you would change?

I think basically I’d just give her a little bit more freeboard and maybe a fuller stern but there isn’t anything that needs changing. Perhaps it would be interesting to have some fun, like bolt on a deeper keel, add a spade rudder and insist on a carbon rig every time. Minor things like that!

A Rustler 42 with a carbon mast
A Rustler 42 with a carbon mast, this has improved her stability and performance

I did put forward, perhaps in jest, that maybe Rustler could consider a Mk II version – everyone seems to be doing them these days – and incorporate few little tweaks that could improve the boat, but it’s an expensive business so they would have to find a customer willing to invest in the tooling costs.

Which Rustler are you’re most proud of?

Probably the 57. It’s big and sleek, it has the right proportion of freeboard and has a sleek coachroof – it all worked out very nicely. I think it’s the best-looking boat of the Rustler range.

Rustler 57
Big and sleek with the right proportions. The Rustler 57 is Stephen’s favourite looking yacht of Rustler Yachts’ range

The keel for the 57 was a little bit difficult, it has a centreplate that is housed completely within the lead keel. It doesn’t encroach into the hull at all, it is all housed below the hull in the stub that the lead keel is attached to. We had to work out a way of lifting it up without allowing water into the boat. It turned out we could have a lifting device underneath the saloon table which took a bit of working out.

What are your thoughts on modern design trends?

All boats would be better with a bit of stern overhang. Modern boats don’t have it and you’re followed around by a constant gurgling of the water from the transom dragging through the water, it’s enough to drive you mad.

At the other end, raked bows were popular until some bright spark thought: ‘you’re paying money for the overall length in a marina berth, so let’s maximise the waterline length and add a plumb bow’. So vertical bows became fashionable, but then everyone discovered that you need a long bow roller to keep the anchor clear, so now you end up paying more in a marina for the bow roller. Why not fill the gap and have a pretty, raked bow and leave it at that? It’s like the donkey chasing the carrot.

What plumb bows have done is added a long bow roller which has transformed into a bowsprit, and bowsprits have earned their place on cruising yachts as the place to fly code zero and asymmetric sails.

The new generation of cable-less furling code zero sails are game-changers. You can put up a nice sail without the bulk and weight of a torsion rope. Because of the way the sail is cut, it yanks the luff forward as halyard pressure is applied. They need to be flown ahead, clear of the forestay. There are two ways of doing this. One is using a bowsprit – if you have a plumb bow, you’ll also have the anchor hanging off it. The other way is to have a proper raked bow with a long overhang, which the Rustler 46 has got. She’ll be fantastic off the wind. Reaching with an asymmetrical spinnaker, she’ll be absolutely flying.

What can else can we look forward to with the new Rustler 46?

I’m looking forward to wowing people with a good-looking boat. I think some people fall into the trap of thinking they want a boat to sleep, cook and eat on when they rarely will. I say don’t fool yourself, get one of these, go for a good blast, drop the hook on a nice day, get the lunch out, then sail home. People will just love the look of the boat, they’ll be bowled over how good looking she is as you sail past.

She has berths, a toilet and a stove for a nice weekend away. By the standards of pre-war boats, she’s like a luxury blue water cruiser!

She’s a proper Metre boat, like an 8-Metre. I like long overhangs at both ends which is what she has. She’s intended to evoke the feeling of a traditional Metre boat.