Extreme 650HT

The Extreme Boats manufacturing plant is set on the outskirts of small rural township of Thornton, near Whakatane in the Bay of Plenty.

Owners Glenn and Diane Shaw bought the company from the previous owners seven years ago, at which time it had just two models on the books. Glenn comes from an engineering background, and with a love of fishing, it was only natural that he would gravitate to boat building.

Extreme Boats now produces seven designs, ranging from 5.5m up to 8.4m. Most are monohulls, but an 8.4m pontoon hull is included in the line-up. The company currently turns out around 50 hulls a year and is involved in exporting to Australia.

Construction

The basic design is a 6.65m (LOA) hardtop monohull with a fine entry running to a 20° deadrise at the transom. There are no planing strakes and fairly substantial down-turned chines are a feature.
 

A design item common to all the Extreme hulls is a self-flooding chamber running along the keel line, formed by welding a flat plate across the top of the keel ‘V’, forming a strong triangular section. The 650 is no different, but Shaw insists this is not really about ballasting the hull. While extra weight along the keel-line will definitely add something to the stability, this self-flooding chamber only holds 180 litres of water when the hull is at rest. The main point of this design, says Shaw, is to add strength to the keel line, drain the anchor well, and to form a convenient pathway to bring water to, and drain, the under-floor holds.

The hull is built from 5083 aluminium, with 5mm bottoms, 4mm sides and deck and a 6mm transom. Four full-length stringers help support the hull, in addition to the flat plate over the keel. Shaw is considering increasing this to six full-length stringers. Four full bulkheads provide lateral support, with additional frames at 120cm centres.

Chines and keel line are fully seam-welded, inside and out. There is a substantial amount of under-floor buoyancy and the three tanks are pressure-tested after construction, as is the under-floor fuel tank. Buoyancy figures were not available, but the hull has been swamp-tested and is built to survey. The build is certified and checked from time-to-time by independent auditors SGS/M&I.

Other features include a substantial rub-rail; off-hull mounting plates for the trim tabs (to avoid drilling holes in the hull); and a Vibra-stop engine mount, which made a quiet engine even quieter.

Over all, the hull is very fair indeed, especially when it is considered that the internal decking is seam-welded to the sides. The lack of heat buckling speaks volumes about the skill of the welders. Glenn Shaw assured me that there was no ‘bog’ used to finish his hulls.

Power and performance

Glen and I launched the 650HT in the Whakatane River, and after a photo shoot in the entrance, ran out to Whale Island.

The notorious bar was fairly calm on our departure, with a modest 10 knots blowing off the land. Out towards the island a moderately tight half-metre swell was running, allowing us to test the boat in what are fairly common conditions. The wind lifted to more like 15-20 knots by our return, with the swell lifting and the surface starting to chop up.  

The 650 HT is rated for 115-200hp outboards; the test boat was fitted with a mid-range 150hp Evinrude E-Tec swinging a 17-inch pitched prop. It was set at a good height and there were no cavitation problems. Fuel is supplied from a 180-litre under-floor tank. In a short speed trial in the lee of Whale Island, the engine delivered 33 knots (61kph) at 5000rpm. This is completely adequate, if a little under the top-end ‘book’ revs for the engine. A slightly finer-pitched prop may allow the engine to deliver even more and a 200hp outboard would really make it boogie.

The handling of the hull in a head sea was lively, but not harsh, especially with the fine entry trimmed down so it could do its work. Heeling over with wind on the beam can sometimes be a problem with smaller hardtop designs, but the trim tabs fitted to the test boat took care of this. Across sea and ‘downhill’ with the bow trimmed up a little, the 650HT was a pleasure to drive. Sea Star hydraulic steering and the BRP throttle and shift added to the ease of helming. Overall, a fine performance.

Anchoring

Walking around the sides to the bow is easy on the 650HT. There is plenty of space, handrails on the roof top, and bow rails most of the way around. Some anti-skid panels could be easily added. The other alternative for the bowman is to stand in the hatchway.

A Lofrans Project chain and warp capstan is fitted, with controls mounted at the helm. A permanently-mounted Rocna size-six modified plough was the anchor of choice, and the fairlead consisted of two guide plates welded straight to the foredeck. An optional protective plate between the bow roller and the capstan should help prevent a flogging chain dinging the foredeck paint.

Layout

The fore cabin sleeps two adults easily, with the berth infill fitted. Two levels of side shelves (one deep, one shallow) provide some stowage, and their padded faces make comfortable back and headrests while seated. A latched panel allows access to the wiring inside the helm console and a flush toilet is fitted under the centre squab. The step-down is bung-drained to the keel chamber already mentioned, and a locking cabin door is available.

The wheelhouse boasts a large dash with a rear retainer/grab rail. A dark marine carpet finish, which stops items sliding around and has the added benefit of cutting internal reflection on the ‘screen, is available on request.

The cool-looking BRP ‘retro’ white dial engine instrumentation and Navman electronics (sounder and GPS) are flush-mounted in the helm console, as is the switching, power take-off, and capstan control. Navman VHF and a sound system are flush-mounted up under the cabin roof.

Interestingly, the helm seat is cantilevered out from the side of the hull, saving a fair amount of space. Stowage on that side is enhanced by two hatched lockers in the side, and an open side pocket. The passenger seating is a more usual king-and-queen type with internal stowage in a fibreglass base. Two levels of good-sized side shelves offer storage space.

Grab rails are attached to the rear edge of the wheelhouse and the sealed chequerplate deck drains to a sump under the transom, from where any water is removed by a 1000gph bilge pump. Along the centreline are two under-floor holds, self-flooding if you remove the bungs. These can be drained by running on the plane with the bungs out.

Two-metre-long side shelves run along each side of the cockpit, with two levels fitted in the helm side, and ‘top hat’ extrusion allowing the fitting of brackets and racks without drilling into the hull. The drop door for the step-through transom has a built-in stowage bracket under the transom wall for when it is not in use. The rest of the transom wall is utilised as a locker with two front opening hatches. Here, the two batteries are stored, along with an isolation switch, oil reservoir, fuel filter, pump for the washdown hose/livebait tank and primer bulbs for the fuel and oil.

Over the transom are boarding platforms (anti-skid finish can be fitted here, too), with fold-down boarding ladder and grab rails. The fuel port is situated on the outside of the transom, to avoid any spillage getting inside the hull. Overall, good use of space, with Extreme not scared to get away from the ‘mirror image’ layout adopted by many manufacturers.

Fishability

The basics for a good fishing platform are all here: a stable hull with good footing and easy cleaning provided by the chequerplate deck, which extends right to the sides. There is good toe room right around the cockpit, and support ranges from the top of the thigh to above the knees, depending on which part of the gunwales or transom wall you are leaning on. A nice cockpit to work from.

Four aluminium through-gunwale rodholders are fitted, with the gimbal pins in correct orientation. There is room for plenty more if required. A six-position rocket launcher on the hardtop provides more rod storage. A ski-pole is mounted centrally in the transom, which also accepts a bait table. A livebait tank is fitted under the transom step-through, which can be used for bait or catch storage if required. The under-deck holds are one option for catch storage and also offer plenty of room for dive gear. Divers will also appreciate the boarding ladder, platform, grab rail and step-through transom.

Excellent potential for a hard-core (but good looking) fish and dive machine.

Trailering

A range of trailers is available with Extreme Boats. The test model was carried on an Agritech trailer, also built in Thornton. A cradle A-frame design, it features strengthening gussets, open-end box-section (allowing full galvanising and easy drainage and cleaning), and tandem axles with zinc-treated leaf-spring suspension. The boat sits on 11 sets of wobble rollers. The trailer is fitted with wind-down jockey wheel, submersible lights, a dual-ratio manual winch and mechanical over-ride trailer brakes.

Ramp launching was easy – the boat didn’t try to run away when I removed the winch hook, but a simple one-handed push had it running over the rollers. Standard towing weight is listed as 1940kg.

All in all

An excellent all-round boat, with good fishing and diving application – and it still looks sharp. A good sea performer, solidly constructed and with a good level of finish. Extreme Boats’s willingness to customise features and finish should allow buyers to get the boat they want.

	This article is reproduced with permission of New Zealand Fishing News   Jan 2007 - by Sam Mossman Re-publishing elsewhere is prohibited