Trailerboat Trials October 2009
By Sam Mossman
Extreme 750 Game King
Based in
Having developed a reputation for being robustly built and well behaved, Extreme hulls were winners of two ‘Boat of the Show’ awards at the Hutchwilco Auckland Boat Show in May of this year. ‘Aluminium Fishing Boat under 6m’ went to the 570 Sportfisher, while the 610 Game King topped the ‘Aluminium Fishing Boat 6-7m’ section; continuing Extreme Boat’s string of awards over recent shows.
The company are known for their willingness to customise their boats – this ability in an advantage of working in alloy. The subject of this month’s test, the 750 Game King, was built for a local
Construction
The 750 Game King features a 5mm bottom (6mm is an option), 4mm sides, cabin and decks, and a 5mm transom. The entry is fine, with no strakes on the hull, downturned chines and a 22° deadrise at the transom. Six fully seam-welded stringers run the length of the hull, with crossways frames at 1200mm centres supporting the sealed 4mm chequerplate decks.
A feature of the construction is the use of a flat plate welded across the hull above the keel. This forms a chamber that is triangular in section, running the length of the hull. It is left open at the transom and vents through the anchor-well at the bow.
There are a number of advantages in using this triangular section at the keel: it adds considerable stiffening to the hull; is used to bring water to, and drain it from, the forward step-down and under-deck holds; and it also acts as a self-flooding ballast tank, filling with water when the boat is at rest, then draining rapidly as the hull lifts onto plane. This is a useful feature to have on a deep-V hull, adding to the stability of the hull at rest.
The welding is competent and robust. In most cases welds have been left unground. This does not look as pretty as a ground finish, but makes for a stronger result and allows you to see exactly what you have in terms of weld quality.
When it comes to the safety aspects of the boat, the owner has taken a ‘belt and braces’ approach, a good attitude in my opinion. An example is the considerable reserve buoyancy (sealed chambers, providing a reserve of 1322kg over and above the weight of the rig) and the fitting of drains in the 280-litre under-deck fuel tank to allow removal of condensation.
This boat was fully painted or finished with marine carpet, except for the cockpit deck. It is also available in outboard configuration.
Power and performance
Rated for 150-250hp, the 750 Game King I tested was powered by a Cummins Mercruiser Diesel QSD 2.8- litre (169cu-inch) 230hp stern drive. (Note that this model engine has now been de-tuned to 220hp.) It was matched with a Mercruiser Bravo-Two leg, a unit designed for launches and houseboats where the large 20” diameter prop and deeper gear ratios provide extra thrust that will get heavier craft up on plane quickly and keep them there at lower speeds. This is probably a useful attribute where regular bar crossing, such as at Whakatane, is a feature of the boating. It is the owner’s intention is to try this rig with other drive units (apparently it is not too difficult to swap them over) and it could be that (sticking this hull with the heavier-duty Bravo series) the sportier Bravo One leg might give a higher top-end speed.
That being said, there is nothing wrong with the performance of the boat as it is. At top revs (3800rpm) using a 19” pitch prop, it turned out 46.7kph (25.2 knots), with a comfortable cruise speed around 30kph (16 knots), depending on sea conditions. According to the owner the loading and speed of the boat makes little difference to the fuel usage (about 1.1litres per nautical mile at cruising) – an effect of the high torque generated by the Bravo Two leg, no doubt.
The QSD engines allow for a nice compact through-transom installation which doesn’t eat too much cockpit space. The engine-well coaming is sealed, but plates can be easily removed from the front and the rear (on the boarding platform) for servicing. The two batteries are well protected but accessible on a shelf above the engine. Dual 2000gph bilge pumps (it is nice to have a back-up) are fitted in the engine well. The fuel tank port is out on the stern platform, removing the possibility of diesel spillage in the cockpit when filling; tank capacity is 280 litres.
The test boat handled more like a launch than a trailerboat, a comfortable soft rider even in the sloppy 1.5m seas we encountered outside Whale Island ‑ coming from a decent blow the day before. The high-torque of the rig allowed the boat to stay on plane at relatively low speeds, making it easy to pick your way through the sea. A nice boat to helm with no vices; the 750 has all the makings of a great heavy-weather hull.
Anchoring
The test boat was fitted with a dual fairlead. One side of this carried a permanently-mounted Sarca anchor; the other was to allow the use of a grapnel in deep water. The owner carries separate ground-tackle with 800m of 10mm warp for this.
The main anchor is retrieved with a South Pacific Pro 800H winch, which is controlled from the helm and feeds into an anchor locker in the bow. This can be accessed, if necessary, through a hatch in the bow bulkhead. The deepwater tackle is lifted with the traditional sliding float system, and this can serve as a standby system for the main anchor as well, following the owner’s program of having back-up systems.
Access to the bow, if necessary, can be gained around the cabin side or through the hatch in the fore-cabin roof. The fairlead will hold a swinging anchor clear of the bow paint and the substantial bow rails leave plenty of room to pass an anchor underneath.
Layout
In the fore-cabin, a flush toilet is fitted under the central berth and a berth infill allows sleeping room for two (or even three) people. A cabin light is fitted and a latched-down plate allows access into the wiring and steering in the back of the console. Stowage is provided by two levels of side shelving; the under-berth space being taken up with sealed buoyancy chambers. A wide entry from the wheelhouse allows comfortable access and an open, airy feel.
Out in the wheelhouse a huge dash is covered with dark marine carpet, cutting internal glare on the ‘screens, and is also fitted with a back rail, doubling as grab-rail and backstop for items stored there.
All-round visibility is good through clear safety-glass windows, including side sliders for ventilation. Only the curved quarters are polycarbonate. The dash is fitted with recessed dials and switching; electronics are taken care of by a multifunction Navman 8120 unit displaying GPS and sounder (with 1000w transducer) , which can also hook up to Radar when fitted. This last unit can be mounted on the same base on the hardtop which is currently fitted with a remote controlled spotlight. VHF and sound system are mounted overhead.
The helm seat is mounted on a Softrider gas shock pedestal with footrest, while the passenger side boasts two bench seats with a small table between. There is internal stowage space in the seats and the table can be lowered to create a short berth. Stowage is boosted by side-shelves set into both sides of the cabin and a small galley unit with a single gas burner is built into the corner behind the helm seat.
Communication and ventilation are both important when gamefishing on hot summer days. Both of these aspects are aided by clear safety-glass drop-windows at each side of the rear of the wheelhouse. These can be set partly open at several heights or recess right down into the lower bulkhead. The central section of the rear wheelhouse bulkhead is taken up by lockable bi-fold doors, also made of safety glass, allowing the skipper to keep a good eye on the cockpit even when the doors and windows are shut.
Out in the cockpit a 60-litre freshwater sink unit is fitted against the rear of the cabin, housing the gas bottle for the cooker inside. A large after-market insulated fish bin sits back against the cabin on the other side of the boat, doubling as a cockpit seat. Grab-rails are fitted to both sides and under the hardtop, which has a removable canvas extension to provide extra shelter.
The cockpit deck is sealed chequerplate and drains to two sumps under the transom. From there, any water is fired over the side by two 3000gph bilge-pumps – serious capacity that will move a lot of water in a hurry. Storage options in the cockpit include side pockets along each side; two-level shelving on one side and a single level for larger items like a landing net, on the other. A large under-deck hold is fitted with bungs and can be flooded or drained (when under way) to the open keel tank. Low level cockpit lighting is fitted for night fishing. A wash-down hose has also been fitted.
As mentioned, the compact engine installation does not eat much cockpit space. To either side, half-height transom cut outs with drop-doors allow easy access out onto the large chequerplate boarding platform, which doubles as a guard for the stern leg. The owner has had a custom removable ladder made for boarding over the bow from a beach, and mounts are to be added to allow this to be used as a stern ladder as well. Under the platform, on the stern, the transducer and trim tabs are mounted.
For a boat of this size, the fit-out has been kept relatively simple and practical, with a emphasis on over-spec safety systems – a good approach for a boat that is to be used in off-shore waters and regular bar crossings.
Fishability
Probably the best way to set up a boat for fishing is fish out of it first to see what you really need and where you need it. This is only possible up to a certain point of course – certain things have to be incorporated into the main build – and this is the case with the test boat <Ital>Cigar<>. The basics are all there: plenty of cockpit room, good footing with the chequerplate deck (an addition of tube matting is being considered); stability aided by the keel ballast tank; and good top-of-thigh support with toe room around the cockpit sides.
The chequerplate boarding platform has been widened by 200mm, and with the pipe railing around the sides, provides a useful fishing platform. The cover over the rear of the engine installation offers a seat while you are waiting for a bite.
A couple of low-level lights are recessed into the underside of the rear rail for night fishing and attracting baitfish. Two 12-volt outlets have been fitted in the rear cockpit with the purpose of running additional bait lights.
A mackerel-sized livebait tank is built into one transom step-through, and after-market tuna tubes could be easily fitted on the platform. Another fitting planned for the platform is a clamp-on rod-holder array for the rear rail.
Currently there are six through-gunwale rod holders fitted and there are plenty of options to add to this number. A large bait and filleting board with overboard drain is mounted on the engine box. On the hardtop is a six-position rocket launcher. Catch stowage can be in the large after-market fish bin (which doubles as cockpit seating) or in the floodable under-deck hold.
As mentioned, the fishing fit-out is very much a work in progress and as intended uses include gamefishing, further additions will probably include outriggers.
Trailering
Trailers are custom made for each boat by Extreme. This one was alloy and gusseted for strength. Design is a tandem-axle, cradle A-frame with leaf-spring suspension. The boat is carried on seven pairs of self-centring wobble rollers per side, with a single keel roller at the bow. Guide-poles with teflon rub-strips at the back of the trailer are an aid to backing (when the boat is off) and to loading in the side-current of the
Trailer fittings include submersible LED lights, wind-down jockey wheel, dual-ratio manual winch, a Carlisle Hydra Star braking system and dual coupling. Tow weight for the rig, dry and empty, is about 2400kg.
All in all
Quite a boat, the Extreme 750 Game King. Robustly built, with its excellent sea-keeping performance and redundant safety systems, it has all the makings for over-nighting and offshore deep-water or game fishing applications. Boats of this size (and cost) are usually customised to a fair extent, and the combination of ideas from the builders and the owner might be characterised as ‘keep it simple, keep it strong’.
Specifications
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Material: aluminium
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Configuration: monohull hardtop
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LOA (customised): 7.80m
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Beam: 2.80m
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Bottom and transom: 5mm
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Sides and deck: 4mm
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Deadrise at transom: 22°
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Recommended HP: 150-250hp
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Test engine: Cummins Mercruiser Diesel QSD 2.8 230hp
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Leg: Mercruiser Bravo two
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Fuel Capacity: 280 litres
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Trailer: Extreme Boats Limited
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Tow weight: 2400kg
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Key turn package (Optimax 225 outboard): $124,608
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As tested: $166,419