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post #3206 of Old 11-08-2012 Thread Starter
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Sydney GTS37

So, why I am making all all this noise about Salona producing Sydney yachts? Are they really that fast?

Let’s look at the dimensions of the 37 and compare them with one of the fastest performance cruisers of about that size, the XP38:

Lengnt : XP-11.58m…… Sydney-11.4m weight: XP- 6775kg….Sydney 4950kg

Beam: XP- 3.70m……Sydney- 3.52m

Draft; Xp-2.40m……Sydney- 2.45m

Ballast ratio- XP-41%----Sydney-?

Regarding Ballast they don’t give the number but that is not by the same reason Benetau does not include that information on the Oceanis line. I am pretty sure that this boat has a B/D ratio at least equal to the XP and probably superior. It has to have to carry all that sail area with a smaller beam.

Sail Area upwind XP- 87.5m2……Sydney- 80.6m2 (the XP with a 106%genoa the S with a iRC Jib)

Downwind Area Xp-178m2…….Sydney – 195m2

So, do you get it? This boat is going to smoke a XP 38 and it will be among the fastest boats around for its size being faster than almost all 40ft performance cruisers.

These boats have to have a hi-tech construction and normally are much more expensive even than a Xyacht. Not anymore, now, made by Salona they announce a great price:

219 000 euros with and aluminum mast and 249 000 euros with a Carbon mast. Well, that is a lot of money for a 37ft but that will be a lot less than what costs a boat with approximated performances like the Santa Cruz 37.

KER says about this design:

The Sydney GTS37 design is the fi rst of the new GTS range which we have been contracted to provide designs for Darren Williams,the MD of Sydney Yachts and a keen yachtsman himself felt that the market wanted more performance rather than just another heavyweight windward-leeward specialist, so having sailed on the Ker 53 Cruiser-Racer and experienced the genuinely high performance cruiser-racer concept Sydney Yachts asked Ker Design to put the latest ideas and technology into the new GTS range.

We first explored the low-road in weight, putting on a fin without bulb in order to reduce the required sail area and keep the rating down, but aside from being competitive we couldn’t really get excited about the concept and couldn't see why the end customers would either. We were stuck in a middle ground with a modern hull shape and form stability in spades but still too heavy to really take advantage of the advanced shape.

So, not satisfied, we threw away what we’d done and went back around the design loop, much lighter with the overall displacement,bulb keel, taller rig.

When we computed the drag with the CFD codes(we mainly used Dave Egan’s Flowlogic code, for which Ker Design recently acquired a 64 processor cluster to allow us to create a full drag matrix) and crunched the numbers in the VPP, we found that not only had we made a significant gain in speed, but the handicap competitiveness was also improved, which was later confirmed by the trial certificate.

Worrying that our in-house CFD results were too good to be true we asked Charles Crosby of Cape Computational Fluid Dynamics to compute some important drag points using different CFD software, but with the differences coming in within 0.5% of relative drag, (which typically equates to only one or two IRC “points” of performance), and in the safe direction, this just added confidence that we were on the right track. The result is the Sydney GTS37 which is able to match the faster 40’cruiser-racers around the track in all conditions, plane away from them as the wind increases and give a very good chance of winning on handicap.

An important side-benefit of this development is that whereas the narrow canoe hull forms of the contemporary IRC cruiser-racers are disliked by the ORCi rule, the more voluminous hull form type we have used in our Sydney GTS37 is well favored, as well as providing more living space below.

Aside from the general performance characteristics, other features we incorporated into the Sydney GTS37 are the ergonomic cockpit layout, twin wheels, carbon rudder stock, stainless steel keel and mast support structure for stiffness and reliability.

The Sydney Yacht brief was to provide a boat for those who have a wish to do a bit of cruising, yet sail fast and competitively, but it also works well as an option for those that want to race the fastest 40’cruiser-racers on-the-water, as well on the handicap board.

Well, Ker knows what he is talking about since its racers are winning practically everything that is to be won:

Results | Ker Yacht Design

So do you get my drift on why I was happy for this boat being produced in Europe at a competitive price?

Besides the boat is beautiful:

In an interview Ker referred to the 37 and 43GTS in a slightly different way, but also an interesting one:

After a number of spins of the design loop, we have finally settled on the high-performance road for the new Sydney GTS37 & GTS43. Reducing the overall weight, maximizing the waterline length and ballast ratio. Not only does this fit well with our general design philosophy, but it also came out of our studies as being the most competitive route, something that bodes well for IRC. The hull shape is also very competitive under ORC.

The origins of the shape can be traced back to research on AC90's (2007-2008), which is perhaps the first time the full weight of AC R&D resources was applied to an unconstrained hull form, leading to some considerable advances over a six month period. Adapting and applying the lessons we learned then and since to the problem of a fair-form IRC racer, we ended up with a powerful but low drag hull form that picks up additional stability when it heels. The transom width is moderate on the sailing waterline but on deck the max beam carries aft to allow the crew to sit further outboard and also give the helmsman very good visibility of telltales and waves.

A strong characteristic of our designs has been that they are all-rounder’s, able to pick up top results whatever the conditions.

The Sydney GTS37 & GTS43 will be no exception, with a generous sail plan ensuring light air performance, good stability for reaching and upwind, while low drag is always helpful! Most of her competitors are relatively heavier.

We found through our CFD analyses that with our powerful hull form we were able to reduce displacement while still remaining competitive in windward-leeward racing but gain a lot of performance downwind as the wind increased and in light air. Of course a great side benefit of reduced displacement is that the boat will be more responsive and fun to sail, the GTS37 being over 10% faster downwind in a breeze than a 40’ racer-cruiser from one of our competitors and the GTS43 even faster!


Last edited by PCP; 11-08-2012 at 10:26 AM.
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