Tomahawk 620 centre console 2024 review

Making a powered catamaran work with a single engine is the white whale for many power trailer boat makers.  Many have tried, but few have been successful – at least with regard to larger-size trailerable cats.   

In the 1970s the Markham Whaler made a reasonably successful 4.0/4.3-metre fibreglass cat with a single outboard engine, but the engine was mounted behind one of the sponsors, not in the centre of the transom.

In the 1990s the Websters Twinfisher (no relation to the author) was successful in producing smaller cats with a single centrally mounted engine, but it took some experimentation to get it right, and some models just did not work.

The problem with mounting the outboard engine in the centre of the transom and in the middle of the tunnel is that the propeller has to rotate in water that is already mixed with air. This creates propeller ventilation with the propeller rotating but getting no grip, or bite, on the water.

Propeller ventilation in a single-engined cat will even occur when running in a straight line. And you can forget about taking corners with any speed as the propeller will ventilate, the engine will over-rev, and the boat will go nowhere.

The solution, and the only way to make a powered cat work well with a single centre-mounted engine is to fit a water/wave deflector/breaker in the aft/stern area of the tunnel between the two outer sponsons. This should allow the engine’s propeller to spin in clean, undisturbed water.

It’s not easy though and it usually takes a lot of experimentation with engine mounting heights and different-sized propellers to get it right.

One boat maker that appears to have the single-outboard engine cat thing sorted is Blue Diamond Marine.

This northern NSW commercial powered catamaran maker has launched the Tomahawk 620, a futuristic-looking aluminium centre console with a unique asymmetric catamaran hull and a reverse-raked twin hull bow shape.

We tested the launch model, a centre console paired with a single 130hp Yamaha outboard engine.

The Tomahawk 620 is the first of what will one day evolve into a family of Tomahawk models.

This single outboard-engined aluminium catamaran will be available in lengths ranging from 4.0 metres through to 7.5 metres, and with a centre console, cuddy cabin, hardtop cabin, and bowrider configurations.

Similar to its larger (up to 14.0 metres) catamarans produced for commercial and workboat applications, Blue Diamond Marine’s Tomahawk recreational models will be available with a high degree of customisation, at least with regard to the deck layouts and interior features.

So you can change the size of the console on centre console models, fiddle with transom coaming heights and widths, and add or subtract features and amenities.  

Our centre console test boat was outfitted to a medium specification, and built in class 2D Survey.

Key features include a vinyl hull wrap to the topsides; an overhead hardtop/rocket launch rod rack; a pair of large hull-side opening doors; EVA foam rubber flooring throughout; transom towing arch; twin boarding steps; navigation lights; and an anchor winch.

With the above features, as well as a Garmin multifunction fishfinder and chartplotter and an Icom VHF radio, our Tomahawk 620CC is priced at around $130,000 with a single extra-longshaft (25-inch) 130hp Yamaha outboard engine and a custom single-axle alloy trailer with brakes and an auto catch/release boat latching system.

The Tomahawk 620 single-engine powered catamaran was designed by multiple 18-foot skiff world sailing champion Scott Ramsden in collaboration with marine engineer Austin Kell.

The catamaran hull has an asymmetric design along with a wave piercer-like reverse-angled bow and stem shape which is very effective in cleaving through bay chop and ocean swell.

Running the full length of the tunnel is the wave breaker/water deflector that not only feeds undisturbed water aft to the Yamaha's propeller but also eliminates tunnel “slap” at displacement speeds.

The Tomahawk has none of that; you can slow-troll directly into the sea offshore without that annoying shudder that afflicts some cats when heading upwind.

The asymmetric shape of the Tomahawk hull also allows it to corner more easily at speed, whilst maintaining quite a flat and level stance through the turn – cats tend to naturally lean out.

Large outer and inner chine flats on each sponson provide lift/buoyancy and more planing surface for improved efficiency, spray suppression and following sea performance.

The Tomahawk is durably built. The hull sponsons and transom are welded from 4.0mm plate alloy, while the topsides are made using 3.0mm thick alloy.

Internally, the Tomahawk has a 4.0mm tread plate welded alloy floor with giant scuppers at the transom to self-drain water quickly out of the boat.

The Tomahawk 620 centre console is not the prettiest of plate alloy catamarans, but it is certainly practical, effective, and built to last.

Essentially, the Tomahawk 620 centre console has one large, rectangular open deck, interrupted only by a dual-width centre console helm station beneath a welded aluminium T-top with rod rack.

For fishing and workboat applications, this open, uncluttered layout is ideal.

I also like the treatment of the forward deck area, which is large enough to be described as a forward cockpit.

Forward of a two-seater bench seat/console safety gear locker, the bow cockpit is 640mm long by 2.26 metres wide. That’s easily enough space for a couple of anglers to stand and fish over the bow.

This deck area is squared off due to the catamaran hull shape, and there is a massive 783mm of freeboard forward so you can securely stand up front in rough weather.

There is ample storage space, too. Flanking a central anchor locker are two wide storage bins with SOPAC hatch covers to enclose the contents.

To each side of the front cockpit, there are wide side storage pockets beneath equally wide side deck coamings.

The only thing missing that would be easy to add are internal coaming bolster pads to make it even more comfortable to stand and work from this bow fishing deck space.

The dual-width centre console helm station is welded to the floor for strength and rigidity. It is made entirely from aluminium and is relatively unadorned.

The console has a full-width angled fascia and a flat dash top surface. Beneath it, there is a storage area with space behind that to access the wiring panel.

On the test boat, the steering wheel and throttle were traditionally mounted on the starboard side with loads of panel space alongside to fit the optional Garmin multifunction fishfinder/chartplotter, Icom VHF, and switch panel.

Above the console, the test rig was fitted with a clear windshield and welded front mounting struts for the T-top.

Fronting the helm station, our test boat was fitted with twin individual folding seat squabs for the skipper and co-pilot, behind which was a full-width padded backrest.

This seating layout works a treat as it makes it easy to switch between standing or sitting at the helm, and the skipper can choose to stand while the co-pilot remains seated.

Other helm seat options are available including a full-width lean seat box with storage and/or a live bait tank, and more.

The self-draining cockpit stretches 2.75 metres behind the helm console aft to what is quite a low transom and outboard well.

Personally, I would order the boat with a higher transom with more freeboard, but the low transom and short outboard splash well works well for some applications.

Either way, there is heaps of uncluttered open deck space for fishing and diving.

On the subject of diving, the test boat was optioned with two large, very sturdy entry/dive/loading doors that open inward to rest up against the transom.

The two opening doors are properly solid and use a heavy-duty hinging system that looks to be unbreakable.

Other notable features include transom corner battery/bilge lockers, full cockpit EVA foam rubber flooring, a pair of sub-floor kill tanks, pop-up cleats, and a towing arch.

The Tomahawk 620’s powered catamaran hull carves up wind and wave chop as well as most other good cats I have tested, but with the advantage that it can do all the cool cat stuff with just a single outboard engine mounted out back.

The boat handles well too. There’s just a slight outward lean during tight turns, and the boat sits flatter and feels more agile than its rivals when cornering and manoeuvring at speed.

The wave/water deflector built into the tunnel of the boat is also effective as I could power out of turns with minimal propeller slip/ventilation from the single Yamaha outboard engine.  

Offshore, the test boat proved well-mannered and easy to control as well.

In a following sea, I could feel the double chines holding and lifting up the bow so that it surfs down waves rather than ploughing into them, and that’s a good thing.

Heading upwind there is some patter from the aluminium hull, but the ride is quite comfortable and predictable.

The test rig was not fast though. We recorded a top speed of just 27.3 knots, although that was with four adults onboard.

In smoother conditions and with only two people onboard I expect the boat would top 30.0 knots.

The hull is rated for a maximum of 150hp, and I would be tempted to fit the larger engine.

Mind you, bolting a larger, heavier motor to the transom might upset the boat’s otherwise excellent balance and stance at rest and underway.

The Tomahawk 620 centre console is a unique, innovative powered catamaran for inshore and offshore anglers, divers, adventurers, rescue groups, commercial operators (the boat is built in 2D Survey) and more.

With a requirement for just one outbaord engine strapped to the transom rather than two, the Tomahawk is cheaper to buy and maintain, and more fuel efficient than a regular cat.

But similar to most good powered cats, the Tomahawk is smooth, safe and stable in the rough stuff, as well as being over-built from durable 5083 marine grade plate aluminium.

I look forward to seeing more of these tough new boats on the water.

Specifications
Model: Tomahawk 620CC
Length overall: 6.2m
Beam: 2.45m
Draft: 350mm
Displacement: 1800kg
Towing weight: 2,200kg
Alloy: 4.0mm (bottom, transom)/3.0mm (topsides)
Engine: 150hp (max)
Engine as tested: 130hp Yamaha extra-longshaft (25-inch)
Fuel: 100L
Passengers: 6

Price as tested: $130,000 including a 130hp Yamaha extra-longshaft outboard engine with hydraulic steering and a four-blade propeller; built in class 2D Survey; custom single-axle trailer with brakes and an auto catch retrieval system; vinyl hull wrap to topsides; welded alloy T-top with rocket launcher rod rack; transom towing arch; EVA foam-rubber flooring; Garmin MFD, Icom VHF radio; dual boarding platforms; dual loading/boarding doors; pop-up cleats; navigation lights; deck lights; anchor winch; bilge pump

Supplied by: www.bluediamondmarine.com.au