The Spirit of Excellence for Nearly 50 Years.

Last Updated: 16 September 2014

Changes: Expanded Maintenance etc. (and roughly edited)

 

Do note that this is a living document, and will be augmented and updated from time to time. Updates and additions will be noted above to help you keep track. We will also use the newsletters to keep you up to date on interesting bits.

-- Tom Gallagher (author, Sykes NA)

I hope that this support section will have something for everyone: insight to our boats for prospective customers, useful care information for existing customers, and some intriguing thoughts on rigging and mechanics to get even non-customers thinking about things in interesting and different ways.

 

 

Introduction: The Gist of Boat Racing

Even if you're not in a boat with the intention of racing it, racing is the inspiration behind our sport and the design of its boats. While there are minimum thresholds for durability and comfort, for example, racing is where boat builders try to push the limit. We do so by addressing three areas in the manufacture of the boats: minimise drag, maximise energy transfer, and optimise the athlete's ergonomics.

 

The bulk of these pages deal with the last point, as this is the area where you as the rower or coach have a major role to play in finding the optimal adjustments and settings. But I reckon it is also important to know a bit about what we do as equipment manufacturers to maximise performance, be it for a championship race or just that quiet elation you may find in establishing an excellent rhythm and run on some quiet weekend morning.

 

 

Designing Against Drag

Let's just get it out in the open that every builder has to give up a little drag to accommodate some other aspect of design, the most basic of which is fitting the crew in the boat. It might seem like an obvious point, but you as the crew need to know there is nothing hard-wired into the sport that says our seats need to be a certain height off the water (typically around 11cm), or that our heels need to be below the waterline. That is to say, designing solely to minimise drag may result in a funky rig too difficult to row.

 

A good example of this was revealed in the initial design analysis for the mould 40 eight. The first mould of that range was designed within the parametres of a world-class junior men's eight: weighing about 80kg (175lbs average) and being able to complete the 2000m race in 5:55. The hydro-dynamic modeling done out of the University of South Australia found the optimal hull shape was much longer and more narrow than any eight you've ever seen. The problem was, of course, that it was so narrow and shallow that most of the crew members would have to sit well above the water line, making for an unstable setup with no practical way of propelling the hull with oars.

 

Later in that process, when the interest was more than academic, the modeling team used a programme used by evolutionary biologists to model population genetics. The idea was to run several thousand of iterations to find an optimal hull shape that fits a crew; effectively using natural selection pressures to find the optimum. That shape -- given the stated concern of getting the seat 11cm off the water and the heels a minimum of 17cm below the seat, and enough beam to accomodate bow seat's hips and the whole of the coxswain's bum -- was entirely different than the optimum with no consideration for accommodating a crew.

 

Many of you know that shape now, having seen the two different shapes of M40 on the water or in your boathouse. It has two distinctly Sykes components to its shape: a semi-circular cross-section through the main part of the hull as well as the associated camber in the keel line. A few other hulls exhibit both of those properties predominantly: mould 20 (1x) and mould 33 (2-/2x). Anyone who has rowed either of those two hulls knows that they are particularly responsive and quick hulls, but that they also have the characteristic of turning easily.

 

This makes sense if you think about what the camber in a hull does below the waterline: it means that the draft of the hull in the far ends is shallow and provides little dampening to any turning/yawing moment provided by an external force, most typically provide by the rower/crew. This means that if you're looking for a hull that easily takes the turns of, say, the Charles River, mould 20 and mould 33 would be good choices. This yawing tendency can be dampened by putting a larger or more influential fin in either hull, but remember those fins are only dampening/counteracting a turning moment, and they do so by pushing against the water which also increases drag.

 

And here is something for you to think about regarding hulls and fins: Do you want a hull/fin that dampens and hides, say, your poor catch timing, or do you want one that exposes it so you can address it?

 

The same question can be framed in a familiar question of trade-offs. We all want to minimise drag, for example, but only insofar as the boat goes straight enough for how we race at the moment. None of us can row without a fin of some sort, as far as I know.

 

In the question of optimising drag, people often focus too much on the influence of crew weight. Depending on your realistic expectations, crew weight may be the second most critical consideration after fitting a crew in the boat. Placing it such, though, must be accompanied with some caution. It shouldn't be assumed that the only factor to influence hull shape will be crew weight, as factors such as anticipated hull speed will change the results of boat shape.

 

This happens with the mould 37 single, as a recent example. In an effort to reduce the camber of the boat as the rower moves for and aft on the slide, and to increase the length of the waterline, we flattened out the hull through the mid-section and moved more of that volume further out to support the hull and lengthen the waterline. As an added benefit, the M37 has more roll-stability than the 26HH, which it is replacing. It's a rare win-win for the big boys, but not such a major factor for heavyweights under 185cm tall and 90kg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Stiff is Efficient

Stiffness is widely and rightly recognised as an important attribute of racing shells. Measuring stiffness, however, is not something most folks grasp and understandably so. Hull stiffness is important insofar as the hull is designed to be a certain shape going through the water, and so it needs to sustain that shape as it runs through the water. It's tough to measure such things, though, as the only boats that really flex much under their own weight out of the water are the big boats, and that's not very reflective of what happens on the water. It's really the smaller boats where the load of the crew can change it's shape from bow to stern, whereas the load of the crew in an eight is more evenly distributed over its length and there is a lot more material to support that mass.

 

The most critical aspect of hull stiffness is energy transfer; in particular between the footstretcher and the oarlock pin. Essentially, these are the only two areas of force application in the propulsion of your boat, and if you think about it, no significant force can be applied to the pin that doesn't originate in the footstretcher board. Even if you're rowing just trunk and arms, you have to brace your hips against the footstretcher board or else the seat will slide as soon as you start pulling on the oar handle and the propulsion will only kick in once your seat hits the slide ends.

 

So stiffness between the pin and footstretcher is paramount, but those two points are connected in two ways: the hull-rigger connection and the rower-oar connection. The latter is what we all work on in our rowing stroke: getting connected at he catch and sustaining that connection through the drive. It's why shooting the slide and rowing the blade into the catch are so inefficient, let alone counter-productive to speed.

 

As for the first of the two connections -- the hull-rigger connection -- it is one of the most convincing arguments for a stern-mounted wing rigger. The stern-mounted wing is proximate to the foostretcher board and is robust in holding its shape under load. There can be deflection in the pin and in the rigger under substantial load, and in this case it's wise to have the top of the pin braced by a back stay. Many lighter and less powerful rowers will not incur any deflection, but still having the back stay on to maintain long life in the rigger is a good idea.

 

The use of a back stay is different from a bow-mounted wing. That bow-mounted configuration has been around for a while, but has grown in favour over the last decade. There's nothing necessarily wrong with bow-mounted riggers in modern composite boats because the hulls are so stiff through the cockpit today that there is little indication that the hulls deflect much over the long length between where the rigger mounts and the footstretcher.

 

It is false, however, to say that bow-mounted riggers deflect less because of their configuration, with the argument often being that since the rigger is in compression, they're in a better position to take the force. There are several arguments to counter this, but the simplest is to point out that if it really is more efficient to have a bow-mounted rigger, the rigger could and would weigh less than the stern-mounted counterpart. More efficiency means less materials necessary to do the same job. Of course, bow-mounted riggers weigh more and that's simply because they have to be beefier to stay stiff under the load on the longer lever. (We all know a longer lever means we need less force to make something move: "Give me a place to rest my lever and I will move the world.") The longer lever is necessary simply because the distance from the mount to the line of work is further than with the mount over the rower's feet.

 

Another indication of the mechanical inefficiency of the bow-mounted design is that it is almost solely used in sculling where the force is substantially less on each pin vs sweep. If it was mechanically efficient, I would think we would see it there more than we are. I suspect that if composite riggers stick around more (rather than aluminium ones), we will see more bow-mounted sweep riggers because they can be stiffer for less weight and can be cheaper than stern-mounted carbon-fibre wings.

 

 And that's likely where the credible advantage in a bow-mounted rigger may be: it's cheaper to produce. Despite the marginally more material needed and possibly expensive parts for holding the pin and adjusting the span, the lack of a back stay may end up being saving production cost.

 

Going to carbon-fibre riggers, though, be it bow- or stern-mounter, will increase production cost over aluminium ones. They're also less damage durable than aluminium and greater care is required to protect them in transport. In that acknowledgment is an excellent transition to the discussions of the materials used in the construction of modern composite shells.

Our new CNC machine is one of the largest in Australia and is capable of making new plugs for new moulds entirely through automation. This way we can work straight off of the CAD designs and have a ready made plug in a matter of days for boats as big as an eight.

 

Watch the time-lapse video of it's installation in the video to the right.

Construction materials used in Sykes racing shells.

 

Modern racing shells are predominantly made up of composite materials like carbon fibre, Kevlar, and fibreglass laminates (layers) and cores of either Nomex honeycomb or various closed-cell foams. The term composite means that the end-product's structure is made up of a reinforcing material -- like the carbon-fibre laminate -- in a matrix that works to hold that reinforcement in its shape. The matrix we use in our laminates is epoxy resin, but there are other resins out there like polyesters. In fact, the gel coat we use on our boats these days is a hybrid that has the toughness associated with epoxy and the UV tolerance of polyesters.

 

The point of the honeycomb core of our boats (or any other make) is to separate two laminates and keep them a constant distance apart, but do so while adding very little weight. By keeping the laminates far apart, it forces one side into compression and the other into tension when under load. The further the two laminates are apart from each other, the more the properties of the materials of the laminate are tested and apparent. This is why when you squeeze on a boat without a core it flexes easily, but less so if there is a core. Still, you'll notice that boats with thinner cores are easier to squeeze than those with thicker cores.

 

Below is a list of the different combinations of construction used in our racing shells in the last ten years and how this affects the qualities of the boats insofar as durability or stiffness or such. It's important to note that, in our experience, while Kevlar has a reputation for being tough and carbon for being stiff but brittle, the laminates in rowing shells are so thin that they often behave more similarly to each other than one might expect.

 

Construction Types:

HC: Two laminates of carbon (at times woven, at other times a stitched biaxial laminate) over a Nomex honeycomb. Where weight permits (most hulls except singles), a fine layer of fibreglass between the gel coat and the exterior laminate of carbon fibre. This construction type provides the greatest stiffness for the weight. These boats come with the top-of-the-range carbon-fibre fittings and are the most expensive boats in the line up.

 

HKCC: An exterior laminate of Kevlar and interior laminate of carbon (typically reversed on the end decks) over Nomex honeycomb. Where weight permits (most hulls except singles), a fine layer of fibreglass between the gel coat and the exterior laminate of Kevlar. This construction type provides excellent stiffness and identical aesthetics to the HC, but with some marginally improved toughness from the use of Kevlar. These boats come with the same high-end carbon fittings as the HC boats, but have a slightly lower price in some cases. It is the prevalent construction in North America from 2007 onward.

 

HKC: (No longer available in North America) This construction type was in many ways the inspiration for the HKCC construction. It was a recognition that these were elite-level shells, but often came in a wee bit heavy for the heavyweight versions vs the HC boats. Part of the reason for this was the need for additional carbon reinforcing over the two Kelvar laminates, and the other reason was that these shells used the heavier plywood footstretcher boards and timber seat tops.

 

SGC: (No longer available in North America.) This is the only non-elite-level construction listed here. While these boats -- once referred to as Tracer single sculls and now called the Initiator line (only available in Australia) -- were made in the same elite-level moulds as the other boats, the idea was to make them more durable and use cheaper materials. This also made them heavier. The main material was S-glass in two laminates over a spongy core called Spheretex. A heavy carbon laminate is carried through the cockpit area to provide superior stregnth and stiffness where it is needed.

 

Finishing materials

Gel coat vs. Paint: The white surface you see on the typical Sykes is not paint, but rather gel coat. The distinction may be academic to many of you, but to those of us who work on boats, it's important. Gel coast is effectively a finishing resin, which is typically pigmented (white most of the time). Like other resins, there are different types: epoxy being the toughest/strongest and polyester holding up better under UV exposure.

 

Therein is the big difference in using gel coat. Our blend of gel coat that we've been using for the last seven years or so is hybrid of epoxy and polyester, gaining toughness from the one and better durability against UV damage with the other.

 

Now, not all of our boats are gel coat. Boats other than white -- coloured boats -- can be gel coat (typically pre-2004), paint on top of gel coat, or just straight-out painted (post-2012). The last option that we're using recently means that we don't have to paint the boat outside of the mould and so means that we don't have to charge for extra steps.

 

No matter whether your boat has a gel coat or painted finish, when it comes to repairs though, keep your life simple and use polyurethane, 2-pack (single-stage preferable) paint to do the repairs. Don't use gel coat. Gel coat is tough stuff and hard to wet sand and polish for the quality of finish that you'll want. We're talking about adding more than two or three times to the time it takes to wet sand and polish. And just because it is gel coat doesn't mean it will match the existing finish any better than paint will.

 

At the factory, we can make boats from scratch with gel coat because we're not sanding and polishing the finish. Spraying gel coat into the mould is the first step in boat construction, and since the moulds have a mirror-quality finish, the gel coat comes out reflecting that.

 

Hardware and Fasteners

Back in the early days of importing boats from a (rationally minded) metric nation to an (irrationally minded) British Imperial Measurement system nation, we decided to stay with metric. That decision was based on a couple arguments: we wouldn't have to change production for boats going to North America, and there were already plenty of metric boats in the US. Plus, most boats in the world use metric hardware, and on that scale, it is the norm.

 

The argument about the expense/difficulty of having both metric and Imperial boats in the same boathouse and how that complicates tools and parts is a curious one. First, no boat has hardware of only one thread size on it, and so every boat house is going to need tools of varying size. Second, most Sykes hardware is a 6mm thread and the hex heads take a 10mm tool; compared the to the expense of the equipment and such, having a few more tools and spares seems at worst a negligible organisational challenge. Yes, it is "one more thing", but if that's the straw that will break the camel's back, I think the camel is done-for in a matter of time anyway.

 

Most folks are hardware illiterate, which is really easy to fix, as we're about to see.

 

Sizing: Hardware is measured by the diametre of its threads and not by the hex-head tool you might need for a hex nut. It's important to understand this, because then you'll know (for example) that a wing nut from your footstretcher will also fit on your rigger bolt. So here is a quick cheat-sheet on the most common hardware on a Sykes.

 

M5  primarily used in shoe screws and in light-work, like holding steering elements. The bolts and wing nuts holding down your slide are also M5

M6  this makes up the bilk of your hardware on the shell; all the rigger bolts and nuts and footstretcher hardware. The hex heads use a 10mm tool.

M8  this it the thread diametre on the top of the pin, requiring a 13mm hex tool

M12  this is the thread diametre on the bottom of the pin, and while it uses a 19mm hex tool, having an adjustable wrench is probably fine since folks don't adjust the span all that often.

 

Another important thing to know about the hardware is that it is stainless steel. Stainless steel isn't the strongest hardware out there, and it's certainly not the shiniest; it's just corrosion resistant. You can see if most bolts and nuts are stainless if they have an A2 or A4 printed on them somewhere.

Sykes Racing North America Inc.

 

tom@sykesna.com

ph 480.234.4912

 

 

 

 

 

Manufacturing Location

Jeff Sykes & Assc Inc.

65 Tucker Street

Breakwater (Geelong), VIC 3219

Australia

www.sykes.com.au