How to Choose the Right Inflatable Dock Size for Your Boat (Australia)

The right inflatable dock size comes down to your boat, not the dock. Start with your motor setup (single, twin or triple outboards, or inboard/shaft drive, and whether you need full trim-up), then your main use case (towing to a sandbar, mooring at anchor, or hosting a crowd), and only then compare dimensions. For most single-outboard boats in Australia, that means a U-shaped dock in the 2.6–3m x 3.5m range; twin and triple-engine boats need a wider configuration built to clear multiple motors; and if you're not towing to different spots each weekend, a simpler at-anchor platform can be lighter and cheaper.

Start with your boat, not the dock dimensions

Most sizing guides list dock dimensions first — 2m x 2m, 3m x 2m, 4m x 4m — and leave you to guess which one fits your boat. That's backwards. The dock has to work with your hull and motor, so the questions worth answering first are:

Single, twin or triple outboard — or inboard/shaft drive? This decides whether you need a single U-shape, a dual or triple configuration that clears multiple motors, or a straight-edge dock for a shaft-drive boat with no outboards at all.
Do you need full motor trim-up? If you're planning to beach the boat or run it up close to shallow water with the dock attached, you need a dock that lets the motor lift completely clear of the platform.
Are you towing the dock between locations, or is it staying on anchor for the day? A dock you're towing at 20-35 knots needs to be light enough to lift and stable enough to sit "on the wake" without dragging. A dock that's mostly sitting still at a mooring has more flexibility on weight versus deck space.
How many people, and what are you doing on it? A jet ski landing pad and a floating party platform for eight people are different sizing problems even on the same size boat.

Matching size to a single-outboard boat

For most single-engine runabouts, cruisers and fishing boats, a U-shaped dock that wraps around the stern is the standard fit — it cradles the boat, gives you a stable wraparound platform, and (on the right model) still allows the motor to trim all the way up.

UDock Single (2.6m x 3.5m, $1,990) — the lighter option. If you're towing regularly and want the easiest platform to lift on and off the wake, this is usually the better call.
UDock Single XL (3m x 3.5m, $2,190) — same shape, more usable deck. Worth the extra weight if you're not fussed about being slightly heavier and want more room for gear, kids, or guests.
3x3 UDock (3m x 3m, $1,990) — a midsize U-shaped option that suits both single and dual outboard models, and is better suited to boats that mostly sit on anchor rather than getting towed or beached regularly. It doesn't allow full motor trim-up (though partial trim is fine), so it's less ideal if beach landings are a regular part of your trips.

If beach access is the main use case with a single outboard — trimming the motor up and holding 3-4m off the sand so passengers and gear stay dry — the Single or Single XL is the right call, since they're the ones that allow full trim-up.

Matching size to a twin-engine boat

Twin-outboard boats need a wider stern clearance so the dock doesn't foul either motor. The UDock Dual XL (3m x 3.5m, $2,190) is built for this — same footprint class as the Single XL but shaped to sit clear of both engines.

Floatables UDOCK Dual and Udock Single enjoying time on the ocean in the Montebelo islands

Matching size to a triple-outboard boat

Bigger centre-console and performance boats — think Axopar-style triple-outboard setups, or larger yachts and vessels generally — need a dock with enough cutout to clear three motors and enough length to keep the hull well clear of the bottom when backed up to a beach. The UDock Triple (3.6m x 3.6m, $2,490) is purpose-built for this. Stock is genuinely limited — it's currently down to the last unit with more due mid-January — so if you're running triples, check availability early rather than leaving it until summer.

When you don't have outboard motors at all

If your boat runs a shaft-drive or inboard engine with a marlin board off the back rather than an outboard, you don't need a U-shaped cutout — there's no motor to clear. In that case, any of our square or rectangle docks work well: tie the straight edge of the dock up against your marlin board the same way you'd rig a UDock, and you've got the same swim platform, boarding and lounging benefits without paying for a cutout shape you don't need.

If you're running a shaft-drive boat but also carry a jet ski or tender, a U-shaped UDock can still be the better call — sit the square edge of the dock against your stern, and use the U-shaped cutout as a bay for the jet ski or tender to dock straight into.

Rafting up: docking isn't just for your boat

However you rig your dock, it doesn't just work for you — the straight outer edges let other boats come alongside and tie up too, turning your dock into a shared, central hangout spot rather than a single-boat accessory. It's one of the most common ways owners actually use them once the whole crew's out on the water.

Custom builds for boats a standard size doesn't fit

Not every boat fits a catalogue size, and Floatables regularly builds custom shapes, sizes and configurations for specific vessels — recent examples include a custom dock built for a Lamborghini 63. If your hull, transom or motor setup doesn't match a standard UDock configuration, get in touch about a custom build rather than assuming there isn't a fit.

Sizing for jet skis and smaller craft - like dinghies

If you're docking a jet ski, or want a compact platform for 1-3 people rather than a full boat-mooring setup, the UDock Mini (2.5m x 2m, $1,390) is the right scale. It also doubles as an inflatable marlin board, so it earns its keep beyond just jet ski duty. The Yoga Sun-Dock is another strong option in the jet ski world — it's a better alternative to a foam-filled sled, since it's inflatable and 200mm thick, giving you a solid platform to tow behind the ski and genuinely usable space once you've stopped.

Floatables inflatable pontoon and water hammock, relaxing on the water at Rottnest Island and Cairns FNQ

When you don't need a boat-shaped dock at all

Not every use case is about mooring a boat. If you're after a floating jetty for a lake or river house — somewhere to board a ski boat over the bow or side without a fixed jetty — that's a different shape problem entirely, best solved by a Y-shaped gangway like the Y-Dock (8.5m, $2,290) rather than a U-shaped mooring dock. And if there's no boat in the picture at all — just a standalone lounging platform for a lake or beach — a dock designed to be paddled or anchored on its own, like the UDock Lagoon, is a better fit than trying to size a boat dock for a boat that doesn't exist.

Towing your dock: it's a trailer, but on the water

Every Floatables dock is towable behind the boat, regardless of shape or size — this isn't limited to one model. The technique is simple: lift the leading edge of the dock up out of the water, generally by tying it up onto your marlin board or into the rails, so the trailing edge sits and rests on top of the wake without dragging. Think of it as a trailer for the water — that's genuinely the best way to picture what's happening, and it's stable towing at anything from 20 to 35 knots.

It's also extra storage, not just a platform. Our own family loads five bikes onto the dock and tows them behind the boat from Hillarys Boat Harbour to Rottnest Island and back. When we get to Rottnest, we simply back the boat up to the beach, and the kids walk straight off the back of the boat, onto the dock, grab their bikes, and step off onto the sand — no wading gear or bikes ashore separately. It's one of the simplest ways the dock earns its keep beyond swimming and lounging.

Check your marlin board height before you decide

One sizing factor that's easy to miss: how high your stern, duckboard or marlin board sits above the water. If it's above 150mm, your dock can slide underneath it instead of sitting flush and secure. In that case, look at adding a set of Marlin Board Bumpers ($445) — these tie into the end of the dock and build the bumper wall up to 400mm, so the dock can't slide under the board and you can tie it in tight against the back of your boat. Worth checking this measurement on your own boat before you order, particularly on larger cruisers with high freeboard.

A word on weight and storage before you decide

Every UDock size packs down into a roll-style storage bag, but bigger decks mean bigger bags and more weight to lift on and off the boat or trailer solo. If you're regularly rigging up alone, it's worth weighing that against the extra deck space — the Single is a genuinely easier one-person lift than the Single XL or Dual XL, for example. All Floatables docks use 200mm-thick PVC with double-layered side walls and a 4mm EVA foam deck that stays comfortable underfoot in Australian summer heat, regardless of size.

FAQ

What size inflatable dock do I need for a single-outboard boat?
For most single-engine boats, a U-shaped dock around 2.6-3m wide by 3.5m long is the standard fit. Go lighter (UDock Single) if you tow often, or larger (UDock Single XL) if you want more deck space and don't mind the extra weight.

Do I need a different dock for a twin or triple-engine boat?
Yes. Twin-outboard boats need a wider stern clearance so the dock doesn't foul either motor — the UDock Dual XL is built for this. Triple-outboard boats, like Axopar-style centre consoles, need even more cutout clearance and length — the UDock Triple (3.6m x 3.6m, $2,490) is purpose-built for this, though stock is currently very limited.

What if my boat doesn't have outboard motors at all?
If you're running a shaft-drive or inboard engine with a marlin board, you don't need a U-shaped cutout. A square or rectangle dock tied against the straight edge of your marlin board gives you the same swim platform and lounging benefits without paying for a cutout shape you don't need.

Can I still tow an inflatable dock behind my boat no matter the shape?
Yes — every Floatables dock is towable regardless of shape or size. Lift the leading edge out of the water (typically tied up onto the marlin board or rails) so the trailing edge rests on the wake, essentially acting like a trailer on the water.

Does Floatables build custom sizes for boats that don't fit a standard dock?
Yes. We regularly build custom docks for specific vessels that don't match a standard configuration, including a recent custom build for a Lamborghini 63.

What if my marlin board or duckboard sits high above the waterline?
If it's more than 150mm above the water, your dock can slide underneath it. Marlin Board Bumpers tie into the end of the dock and raise the bumper wall to 400mm, so the dock sits flush and can be tied in tight against your boat.