words - David Lockwood
Another recent entry to the Aussie market, Mariah's new SX18 bowrider boasts a smooth-riding hull, decent internal volume, sporty performance and space for the family - and all for less than $40,000. Dave Lockwood reports
Despite what Split Enz said, history has a habit of repeating itself. Today I've turned full circle and am back at the coalface where I cut my boat-testing teeth many moons ago. The mighty Georges River, which wends its way for kilometres through the southern Sydney suburbs, is where I gingerly set foot aboard a Caribbean 26 for an inaugural published test in a boating magazine more than a decade ago.

While the ensuing years have made me somewhat wiser, I am no less taken by the wide brown tract that spills into bustling Botany Bay and out to the Tasman Sea, which ranges west under various road and rail bridges, past lofty waterfront homes and stoic sandstone boat sheds, to the grotty industrial areas and the beautified parks and housing estates.

There's been a lot of water under the bridge for Mariah boats over the past decade or so, too. The American boatbuilder shot from humble beginnings in 1989 to stellar heights a decade later, with turnover of $48 million and almost 200 dealers. So you might well understand the angst that followed when founder Jimmy Fulk sent a letter to his 300 staff in 2001 telling them he was closing the factory.

But as they say, every cloud has a silver lining. Today the Renken family, which has been building boats since 1957, and also makes Seafox craft, is at the helm of this resurrected household name. And the big American is back in a bigger way, with such reassuring features as a limited lifetime hull warranty on all its boats and, closer to home, established dealerships looking after the badge and its buyers.

The boat ran well on the wilds of the Georges River. A brisk southerly had turned Botany Bay into a washing machine where a Mariah and its likely family owners wouldn't venture. While I did little more than create the biggest wake I could and charge through the melee, I didn't discern a savage bump aboard. Providing the bow is sluicing through the water, the SX18 Bow Rider is a smooth-riding boat.

The 18-footer has volume and buoyancy, and while it isn't especially wide at 2.3m across the beam, it has high sides and a deep bow that collectively shed water and prevented slop splashing aboard.

Some scalloping and rakish lines give the SX18 a sporty appearance. Add an upgraded 4.3lt 190hp V6 MerCruiser petrol motor, as opposed to the standard 135hp four-pot 3.0lt model, and the performance is commensurate. The top speed of 42.6kt (81kmh) with three adults and little gear was consistent with Mariah's published figures.

A composite, timber-free, contemporary construction method is used to build the Mariah range, which spans six models of bowriders from 18–25ft, four cuddy cabins 19–25ft, and three deck boats from 21–25ft.

 On each model the transom is cored, the floor is reinforced with high-density foam, foam-filled stringers are 'glassed to the hull, and closed-cell foam is added for flotation. The GRP is hand-rolled and you can choose between four colour-coded gelcoat stripes: Aztec yellow, electric blue, pitch black, or ruby red on the test boat.

As mentioned, there's a good spread of stainless steel winking back at you from the decks. It's used for the rub rail, swim ladder, (optional) pop-up cleats, grabrails, facias protecting plastic through-hull fittings, and for the windscreen uprights. In fact, the windscreen is so well supported that the agent lifted himself bodily from it without so much as a creak from his joints or those on the boat.

To these things you can add high-density vinyl upholstery and an all-weather marine carpeted cockpit floor (snap-in optional). The alternative seen here was a no-charge non-skid finished fibreglass floor that will be easier to keep clean. The boat's fully GRP liner provides a neat finish to the eye.

The dash is an injection-moulded low-glare insert with automotive-like layout. There is room for improvement in its finish, the upholstery and some concealed fibreglass areas on the demo boat. Upholstery and finish are earmarked for attention on the relaunched brand.

The agents were working with the local manufacturer, I'm told, and apparently Mariah has acquired the old Quintrex factory in America with the aim of turning it into a dedicated high-grade upholstery plant. That being the case, I would expect improvements in the details in future boats. But by and large, the SX18 was a formulaic bowrider without any surprises.

While the factory touts an eight-person capacity on this boat, you'll find the 18-footer pretty squeezy with that many aboard. Think six and you'll be comfortable and four for optimum performance.

There's a choice of full-width rear lounge or back-to-back seats either side of the engine box. The former, as seen here, provides superior seating and better sound insulation. Plus you get a ready-made sun lounge, so you can work on your tan.

While it doesn't break any new design grounds, the SX18 has an anchor well in the bow. Although small, it at least provides somewhere to stow your anchor without have to lift up seat cushions and drag muddy ground tackle aboard. An anchor well on an American boat like this really is a rarity.

 Both under-seat storage compartments in the bow were lined and the centre moulded compartment, which drains through to the bilge, is intended as a forward icebox. You get drinkholders in the bow and enough depth that your knees aren't up around your ears when seated.

The companionway back through the safety-glass windscreen was wide and inviting. The windscreen has glass side panes, which isn't always the case on budget bowriders - some competitors have no side panels at all and the wind blasts your neck while driving.

Storage in the cockpit ranges from a rubber-lined subfloor ski locker with slatted Starboard-plastic lid for ventilation to moulded sidepockets with drinkholders and an insulated icebox ahead of the co-pilot that drains overboard. There is also a glovebox concealing the Clarion CD player with four speakers. A dash switch lets you instantly cut power if you need to be heard.

The sculptured rear lounge needs side grabrails. It lifts on gas struts to reveal a storage space to starboard of the motor and the engine-start battery to port. You can dip the motor oil and access the header tank in case you need to top the radiator with fresh water. The sterndrive leg was the base model Alpha One, with a trailer tilt switch (optional) on the transom, where you will find a full-width boarding platform, concealed ladder and skihook.

The trailer was a decent single-axle Sealink model superior to many imported cradles made for lake boat ramps. Various covers are listed options - the dealer had a higher bimini top than is supplied by the factory cut by a local company - and I would seriously consider an optional hour meter and digital depth sounder.

The helm bucket seat adjusts every which way and includes a flip-up bolster for more height, so you can see over the bow when driving the boat back on its trailer. The seat also locks into position so it doesn't swivel as you cross the waves and sweep through the turns.

 On the automotive-type dash you get a 12V accessory plug for the mobile phone, spare accessory switches, and rocker switches for the horn, bilge blower, bilge pump, stereo, nav and anchor light. Engine gauges included a speedo, which was reading high, and a trim gauge.

I've got big hands and on occasion when turning the sports steering wheel they knocked the throttle which is alongside. But for all intents and purposes, this was a fuss-free bowrider to drive and the vision of the river ahead was clear.

The moderate-vee hull with 18 degrees of deadrise held a slippery low planing speed of 19kt (36kmh) at just 2600rpm. Low-speed cruise at 3000rpm with half trim gave 24kt (46kmh), but the SX18 seemed happiest at about 3500rpm and 30.5kt (58kmh). So expect to reach your favourite family picnic spot in no time.

We passed under bridges, arced around bays, swanned past waterfront houses, and drove down the straights at fast cruise or maximum continuous revs of 4500rpm and 39kt (74kmh) and at 4800rpm for a 42.6kt (81kmh) top speed. And at high speed I could discern no handling flaws.

It's not based on rocket science, nor does it attempt to reinvent the wheel, but for a lot of family boaters the Mariah SX18 has everything they require in a trailerboat. Add a big river like the mighty Georges, or a bay, some watertoys and tow ropes, refreshments and a packed lunch, and you've got the makings of a fun-filled day afloat.


  • Composite construction backed by limited lifetime warranty
  • Hull didn't appear to bang during circuit work or while crossing wake
  • A nice package with a spacious cockpit for four
  • Comfortable seating and buoyancy to support crew riding in the bow
  • Plenty of top-end poke with the upgraded engine


  • Upholstery and finish in some areas could be improved
  • No grabrails for passengers on rear lounge
  • Swimmers must step on upholstery of rear lounge to access cockpit
  • Small fuel capacity, especially with upgraded motor
  • Wheel tight to throttle

PRICE AS TESTED: $35,990 w/ 4.3lt 190hp MerCruiser on single-axle Sealink trailer
Covers, bimini top, pop-up cleats, sound system, safety gear and more
PRICED FROM: $32,990 w/ 3.0lt 135hp MerCruiser engine on single-axle Sealink trailer
Material: Foam-filled GRP hull w/ composite transom, stringers & floor
Type: Moderate-vee planing hull
Length overall: 5.50m
Beam: 2.30m
Deadrise: 18°
Weight: Approx 1048kg w/ base motor/TD>
Rec/max hp: 135/190 sterndrive
Berths: Catnap on the sun lounge
Fuel capacity: 83lt
Water capacity: BYO bottled
Make/Model: MerCruiser 4.3L
Type: Inboard V6 four-stroke petrol motor
Rated hp: 190hp @ 4400–4800rpm/TD>
Displacement: 4.3lt/TD>
Weight: Approx 385kg/TD>
Gearboxes (Make/ratio): Alpha One sterndrive/TD>
Props: Standard alloy
SUPPLIED BY: Blakes Marine, 1 Railway Road, Mulgrave, NSW, tel (02) 4577 6699, For interstate dealers call the importer on 0421 107 661, see or email

Published : Thursday, 1 September 2005

Prices and specifications supplied are for the market in Australia only and were correct at time of first publication. makes no warranty as to the accuracy of specifications or prices. Please check with manufacturer or local dealer for current pricing and specifications.

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