Sealine S335 Review (2025 Edition) by Aquaholic

On Deck

The Sealine S335 has a focus on open cockpit living. Where the C335 coupe closes you in with a deck saloon, this S model strips that back for a full-on outdoor experience. This boat was shown with the optional extended bathing platform, which is not a hi-lo one as on a 10m (33ft) boat, you don’t want the weight of all that mechanism, but it’s long enough to carry a lightweight tender. Owners can choose a passerelle or davit system for launch and recovery, though many will simply lift a small tender on board.

The extended platform’s biggest trick is how it works with the aft seating. The seatback folds flat to create a large sunbed, and with the platform extended, you can still walk right round to the transom without disturbing anyone stretched out in the sun. From here, you’ve easy water access for swimming or diving.

Side deck access starts right from the cockpit with moulded steps and a grab rail at hand before you’ve even stepped up. The decks themselves are comfortably wide, with another handhold on the coachroof. Forward, the foredeck is kept flat for ease of working, with sunbathing cushions over the owner’s cabin hatch. These lift clear when the hatch is opened. There’s an electric anchor winch and chain locker forward, plus neatly integrated navigation lights, horns, and antenna up on the hardtop roof.

A sliding roof panel over the cockpit lets you adapt shade and airflow at will. Both forward and aft sections can be opened or closed independently, and a canopy zips into the hardtop grooves to fully enclose the area.

The main galley provision is split between the cockpit and the lower deck. On deck, there’s a neat outdoor catering station with a sink, two-burner gas hob, fridge beneath, and useful storage. It’s geared to casual meals rather than elaborate cooking, which suits this style of boat.

The cockpit’s social space is generous, with a dining table and surrounding seating, all within reach of the galley and under the shelter of the hardtop. Optional solid side windows with sliding panels keep things practical – they’re quick to open without the faff of flexible panels, though those are available for owners who prefer a completely open feel.

Below decks, the interior keeps to a practical, owner-operator layout. A secondary galley area here adds another two-burner hob, a sink beneath a hinged worktop, extra storage, and another fridge. Hardwood flooring runs throughout the lower accommodation, so easy to keep clean and less fussing over footwear.

Owner's Cabin

The owner’s cabin is forward, and for a 10m boat, the space is impressive. In this layout, the berth is fixed, but Sealine also offers a convertible U or V shaped dinette with a table that drops to form a bed, a flexible option for owners who want more seating for daytime use.

Natural light comes from hull windows and an overhead hatch. The hatch has sliding blinds and an insect screen for comfort. Hanging space and illuminated storage niches add to the practicality, while hardwood floors keep the finish smart and durable.

Second Cabin

Aft on the lower deck is a full-beam guest cabin with a double berth running across the hull, opening hull windows for light and ventilation, and storage including a hanging locker. If the forward cabin is set up as a dinette, this aft cabin naturally becomes the primary sleeping space for the owner. The arrangement works well for two couples, across the two cabins.

Engine access is via a cockpit floor hatch with an electric lift: press the switch, and the whole section swings up to give excellent overhead clearance. There’s enough room to step down between the twin engines for servicing. Batteries, lighting, bilge pumps, and key systems are all within easy reach.

Power here comes from twin 3.0-litre Mercury Diesel engines (previously badged MerCruiser) producing 270hp each, driving through sterndrives. Performance is well matched to the hull, with top speeds in the 33-34 knot range and an easy cruise in the mid-20s. At that pace, the ride is comfortable and composed without pushing into the harsher end of the speed envelope. Range is around 200 nautical miles and typical for this class.

From an ownership point of view, the Sealine S335 is pitched as a relatively simple, low-hassle sportscruiser. There’s no hi-lo bathing platform or complex tender garage, no hydraulic hardtop, and no generator in this configuration; all of which keeps weight, complexity, and maintenance spend down. That means fewer moving parts to service, less to go wrong mid-season and a more predictable annual servicing bill.

The Mercury Diesel sterndrives bring their own pros and cons. On the plus side, sterndrives deliver lively performance, handling and trim control for getting the best out of this hull. They’re also lighter than shaft drives, improving fuel efficiency at planing speeds. On the flip side, sterndrives do add to annual servicing costs, as each leg needs oil changes, bellows inspection/replacement and anodes checked. Budget for this on top of standard engine servicing. In the UK market, twin-diesel sterndrive packages typically command a healthy resale value in this size bracket because they’re seen as a good spot for speed, efficiency, and shallow-water access.

Compared with the Sealine C335, the S335’s open cockpit design tends to suit seasonal, fair-weather use, which can mean fewer annual engine hours and slightly lower wear, though the C335’s enclosed saloon better protects fittings over time. Against rivals, the Galeon 335 HTS offers similar sterndrive performance but with a more enclosed, feature-rich layout that can add to maintenance, while the Bavaria SR35 HT combines cockpit living with a sheltered helm and beamy stability, its upkeep likely on par with the Sealine. For buyers, the choice often hinges on exposure versus shelter: the S335 being the pure outdoor cruiser, the C335 and SR35 in the middle, and the Galeon leaning towards enclosed luxury.

The Sealine S335 trades the coupe comforts of its C-branded sister for pure open-air sportscruising. The cockpit is the heart of the boat as it's a flexible, shaded or sun-soaked space that flows naturally to the water via an extended bathing platform. Below, the layout is adaptable, offering either a fixed-berth owner’s cabin or a convertible dinette, alongside a full-beam guest cabin and enlarged heads compartment with separate shower; a notable upgrade over the older Sealine 330.