New Sea-Doo ST3 watercraft hull: First test

After more than a decade of racing around the track, Sea-Doo has put its long-serving S3 hull out to pasture. The new, cutting-edge, three-seater ST3 hull has arrived at the gate champing at the bit. In watercraft years, the two hulls are generations apart. In today's world, that means a new generation of riders will find more reason to saddle up and ride a three-seater in company.

In simple terms, the new ST3 hull gives you more of everything. Considerably more. It’s more stable, with a lower COG, and a really planted footprint. That’s because it's considerably wider, albeit shorter than the old S3 hull it supplants. Yet its improved power-to-weight ratio makes up for the increased drag. Sea-Doo says mid-range acceleration actually improves 17 per cent from 30-60mph (48-96km/h) on the new RXT-X 300 versus the older model.

Depending on which 2018 Sea0-Doo you choose, the new ST3 hull is more than 39-40kg lighter than the old S3 hull thanks to the reduced hull length and a clever new two-piece (instead of one-piece) seat design. Sea-Doo’s closed-mould CM-Tec thermoformed hull construction also helps keep weight in check. The moulded finish is smooth inside and out.

But with considerably more waterfront real estate back aft — the most space of any watercraft on the market today — the wide ST3 hull changes things up in the competitive PWC market in more ways than one.

On the transom, using the new LinQ snap-in accessory system (our story), you can add an icebox or a 15lt fuel caddy, a storage bag atop that... or remove it all, including the second half of the new seat, for a huge, almost-boat-like, aft deck. Sea-Doo calls it a living room.

None of this just happened along, mind you. The new ST3 hull is said to be product of three years of R&D using an extensive and dedicated design team, on-water and offshore testing, pro riders, GoPro footage and plenty of tweaking and fine tuning.

While watercraft are a gateway to boating and adventure, with more people keen to jump aboard, first timers have also said they want more stability and functionality to get them aboard.

James Heintz, Global Product Manager for Sea-Doo, told us the ST3 hull is the "best performing hull for the offshore environment that we’ve ever been able to fabricate."

Check our off-the-cuff interview with Heintz at the 2018 Sea-Doo launch in Needles, California, as he explains the intricacies of the new ST3 hull…

THE NEW HULL DESIGN
The forefoot or entry of the new ST3 hull is
the same as the RXP, with an aggressively sharp 22 degrees of deadrise.
There are re-profiled strakes and chines, from rounded to a hard edge.

Heintz from Sea-Doo described the ST3 hull design as a huge innovation for the company. There’s a
lot of science in the running surface and it was great to drill down
into that with him.

"The first big piece of this hull is its deep
vee. This has a very sharp angle from the keel line to the mid-line of
the hull to create incredible penetration through waves and really good
comfort and control when in heavy conditions.

"Once we move up
from the deep vee we have really nice re-profiled strakes which help
give really straight tracking and steady control at high speeds."

The first chine is now a hard chine, whereas on the T3 hull it was a soft chine.

"This
gives us a lot more stability and control when we might be pitching
from side to side in heavy conditions, which we all know we experience
when riding offshore… and in waters like off the coast of Australia," he
added.

Meantime, the key to the wider platform is found in the
upper hull sections, where there is a second offset chine and the
Sea-Doo hull steps out, facilitating a bigger deck.

"This is what gives us our added inch (2.5cm) of width on these new models [the chine is half an inch wider on either side].

"It
builds up a column of water underneath this chine, which really gives
us enhanced stability when at rest and even more control in heavy
conditions and at high speed.

"These elements, baked into the
design of this new hull, will allow our riders to be more confident in
offshore conditions, go further and be more comfortable than they ever
have [been], which will help them redefine what they’re able to do on a
watercraft," Heintz says.

Having sat mid-pack on these at-times frenzied international media events on the old S3 hull, I can tell you, the new ST3 was a godsend in that washing machine environment.

Our two days of riding saw us play nautical hopscotch aboard 14 of the 20-in-total 2018 Sea-Doos in existence at the time, while crossing through three U.S. states including Nevada, Arizona and California on our adventure.

With a follow-up day of free riding, we got a good feel for the way the new ST3 hull performs underway... on the triggers — that is, accelerating and iBR braking — and back at rest just bobbing about or pulled up on a beach.

On the old S3 hull, you sit up high and upright. The new more steamlined ST3 hull has a driver’s seat that’s 1.4in (35mm) lower and a second/third seat that's 3in (75mm) lower than the old slogger. That adds to your confidence, doubly so with extra crew aboard. Yes, the improved stability should help attract newbies to the watercraft market.

You can now climb aboard the Sea-Doo from the side of the hull rather easily, stand in one footwell and cast a line, position yourself with one foot on a gunwale, and basically move about the hull without teetering in an alarming way. There are now many more things to do and greater possibilities than just hooking into the eye-wateringly exciting ride.

Having said that, the new ST3 hull offers beautiful handling. It carves a deep path, rolls the spray aside, and bites harder the more you push it. The new ST3 hooks in and wants to go hard on a rails' run, whereas the old hull would tend to bang and buck like a rocking horse. This is more of an RXP-X ride experience.

Using an improved iBR Gen 3 braking system with a new reverse gate or 'bucket', the new 2018 Sea-Doos are impressively quick to stop. Fully depress the iBR trigger on the left handlebar when you're flying along and the effect is immediate. Thanks to a new reverse-gate design you can turn the handlebars and the hull turns during this rapid braking phase. Thus the 2018 Sea-Doos are not only more agile, and the faster watercraft to stop, but also safer.

2018 MODELS WITH THE ST3
The new ST3 hull is available on seven different 2018 models (full reviews to come). These include the GTX range — from the naturally-aspirated GTX 155 popular with fishos, to the supercharged GTX 230 and GTX Limited 230, up to the top-of-the-range luxury GTX Limited 300, which really pushed our buttons.

The new hull also underpins the Wake Pro 230 tow craft, which has a trick ski pylon as standard. Then there is the Performance range: the RXT 230 and, moreover, the hot RXT-X 300, which is the most powerful model in the fleet and rivalled only by the race-bred RXP-X 300. It's the Sea-Doo that gains the most from the new hull.

A key point to note here is that the new ST3 hull takes inspiration from the deeply-veed and deeply-carving T3 two-up hull on the RXP-X. Only with more space, storage, accessories and application, the seven new 2018 three-seaters have greater riding appeal. You can, for example, tow off all the 2018 models since you can carry an observer and a rider to your spot.

VERDICT
This story doesn’t end here. The new ST3 hull is just the platform upon which Sea-Doo has designed its seven new 2018 models.

With some real innovation in the modular seating, storage access, snap-in accessories and rear deck lounging space, Sea-Doo has made the watercraft a more functional utility vessel and further validated its functionality.

Given the nature of our waterways in Australia, and the way we are using our PWCs for more than just point-and-shoot performance, we predict the seven 2018 model Sea-Doos built upon the new ST3 hull will become firm favourites. Stocks are already shipping. Take my money.

Our reviews of the 2018 Sea-Doo line-up and further features will follow. Meantime, more on the 2018 Sea-Doo range news in this release.