BOAT REVIEW Offshore 650 Pro Dive

May 2020 Trailer Boat Reviews
Words by John Eichelsheim. Photography by John Eichelsheim and Supplied.
Build Quality
MODEL Offshore 650 Pro Dive
DESIGNER Alan Walker
BUILDER Offshore Boats NZ
CONSTRUCTION 8mm hull and transom, 5mm topsides and decks
LOA 6.5M
ENGINE Yamaha 150hp four-stroke O/B
Weight on Trailer 1800 kg
Max Horsepower 200hp
Passenger Capacity 4 people
DEADRISE 18 degrees
  • Heavy-duty hull and high-quality construction
  • Exceptional ride
  • Uncluttered cockpit and simple Pro Dive layout ideal for divers, but also available in hardtop and centre-console versions

Jonathan Barlow and the crew at Offshore Boats NZ gave boat designer Alan Walker a very specific brief for the Offshore 650: ride, ride, ride!

Ride, says Jonathan, seems to be a secondary consideration for some trailer boat manufacturers. Other attributes – internal volume, interior layout, styling, stability at rest, ease of manufacture and price – tend to be higher on the list of priorities for many. But for the Offshore 650, Jonathan wanted a robust trailer boat that first and foremost travelled well. It needed to deliver comfortable, safe performance on the water.

The Offshore 650 is a completely new design, available in soft top (Pro Dive Series), centre-console and hardtop versions. It’s not a development of an existing model, nor a stretched version of something else, says Jonathan, who was a commercial diver earlier in life.

The underwater lines are optimised for ride quality, but with plenty of buoyancy forward, 18° of deadrise at the transom and a unique folded chine profile.


Most notably, the hull is constructed using 8mm aluminium plate, which is almost unheard of in a boat of this length. 8mm is also used for the transom with 5mm for the topsides and decks, so this is one heavy-duty tinny!

But it’s not all about material thickness. Under the floor there are two stringers either side of the keel, three cross-members and the 200-litre fuel tank is a separate element constructed from 5mm aluminium. The chine also adds strength and rigidity, since it’s formed from the hull plates, folded for two-thirds of the boat’s length rather than welded to the hull. As a result, the boat’s sides pull down very slightly towards the transom and there’s also a slight kick in the hull’s trailing edge which helps control bow lift.

Of course, all that heavy-gauge aluminium, expertly welded together, costs money. So does the superb CAM custom aluminium trailer and the boat’s striking metallic paint job. So, for a simple fish and dive boat, the Offshore Boats 650 Pro Dive is not the cheapest, but the package delivers value in every respect that’s important: performance, ride, durability and utility.

The trailer is a tandem-axle design with hydraulic override brakes on both axles. A Boat Catch system allows no-fuss drive-on trailering. Weighing in at 1800kg on the road (dry), the Offshore 650 Pro Dive is a heavy boat for its size, especially considering its minimalist interior. But, as we discovered, the extra weight pays dividends on the water.

As reviewed, instead of seats, the 650 features a pair of padded, upholstered leaners with backrests. These are actually very comfortable and offer good support in rough seas, supplemented by strategically placed handrails and a reverse lip at the top of the dodger to hold onto. Constructed from alloy pipe, the leaners friction-fit into holes in the gunwales, so the floor remains clear. They can be removed and stowed forward if a completely open, uncluttered deck is required. Conventional pedestal-type bucket seats are an option.

This is the Pro Dive version of the 650, so an open cockpit/deck was a priority. The cockpit is massive with full-length shelves wide enough for dive bottles. U-deck panels inside the shelves prevent dive bottles scuffing the boat’s Nyalic-coated sides.

U-Dek is used on the cockpit sole and inside the forward cabin, as well as on the coamings and foredeck. It’s even used to cap the trailer mudguards. Tough but resilient, it adds comfort underfoot, feeling warm on a cold day and cool when it’s hot.

The vessel’s low bow rails are distinctive, providing ready handholds when the boat comes alongside or for launching and retrieving, and climbing aboard over the bow is much easier in a beach-launch situation.

Across the transom, twin batteries, the isolation switch and fuel priming bulb are well protected behind a pair of So-Pac hatches. There’s a washdown outlet and hose on the starboard side and a live bait tank under the lift-out transom on the port side. The live bait tank lid features a gas strut to hold it open – handy when you need both hands to wrangle wriggling baits.

Pumps for the washdown, bait tank and tuna tubes (one in each corner) are housed outside the boat inside the outboard pod. That means there are no through-hull fittings, so no risk of inadvertent flooding should one fail. The bilge pump is positioned in a deep sump amidships aft and there’s a fuel overflow chamber and breather to prevent spillages inside the boat. The filler is outside on the transom.

Up forward there’s a very basic cuddy-style cabin offering dry storage, including a pair of pipe-berth type shelves to keep gear off the deck. At floor level, low-slung pipe rails stop loose items, gear bags and boxes sliding around, but leave a central a walkway clear for easy access to the foredeck.

To facilitate this, there’s a step to stand on and a huge hatch in the dodger. Ground tackle comprises a Max Set 6 stainless steel anchor, a rakish polished aluminium box-section bollard and a Maxwell RC6 capstan. A Lone Star free-fall drum winch is an option.

This is a soft top model with a very substantial Auto-sol polished 36mm diameter aluminium frame incorporating a nine-position rocket launcher and a pair of VHF aerials, the whole structure hinged to fold back into the cockpit for garaging. There are also six through-coaming aluminium rod holders and provision to fit game poles.

The soft top is very rigid, so there’s no rattling or shaking underway. Wrap-around clears are an option, but for normal use the dodger and lip do an excellent job of deflecting the slipstream away from the boat’s occupants.

This boat might be simple inside, but it’s equipped with powerful electronics. A bracket-mounted, 12-inch Simrad NSS EVO3 is loaded with Platinum charts and a CHIRP fish-finding module processes echoes from a 1kW transom-mounted TM260 transducer giving clear tracings of the bottom contours at most speeds. A Fusion Bluetooth stereo system takes care of onboard tunes while the VHF is a GME unit.

This 650, Offshore Boats’ demo model, is powered by a Yamaha 150hp four-stroke outboard. One of the design criteria for the 650 was the ability to cruise at 28-30 knots in a range of conditions. This ambitious goal has been achieved, with the boat’s ride only improving the faster you go.

On review day we had a modest wind against tide chop inside Whangarei Harbour – standard conditions anywhere in New Zealand. But for many similar-sized boats, we would have had to throttle back in the interests of comfort. Not in the 650. It just sliced through the chop, revelling in the conditions and delivering a soft, dry ride even without the benefit of trim tabs.

It was equally good running downhill and dry too, even though the chines taper away towards the bow. The boat’s stable, another important design parameter for this model, helped by wide coamings that keeps occupants well inside the boat, thighs in line with the chines. Another advantage of the heavy hull plates and minimal superstructure is weight low in the boat – no need for a flooding keel for stability at rest or extra mass in rough conditions.

The Pro Dive’s gunwales are reassuringly high, there’s good toe-room, and the boat doesn’t heel over alarmingly when you throw it into a tight turn. In fact, tight, high-speed turns are great fun, the 650 simply going where it’s pointed.

And while 150hp is at the lower end of the horsepower range for this model, it still propels the review boat to 40 knots. Equipped with a 17-inch stainless steel prop, performance through the rev range feels strong. More horsepower may be required if you regularly carry a boatload of 100kg-pus scuba divers with all their gear, but for most applications 150hp would be ample. However, the faster the 650 goes the better it rides, so the extra horsepower may be welcome…

For us, cruising at 4300rpm and 25 knots was comfortable enough, but at 32 knots it was smoother still!

With the 650, Offshore Boats NZ has delivered a high-quality aluminium trailer boat that looks great, rides exceptionally well, and is so robustly built, it should be pretty much bullet-proof.

In the Pro Dive version, it’s a simple rig, offering a large, uncluttered working cockpit, diver-friendly side-pockets, plenty of standard features for the keen angler, quality electronics and a custom aluminium trailer. Creature comforts are minimal, but it scores points for versatility due to its open nature and useful cuddy cabin storage.

But above all, this boat impresses with its superb ride. When discussing the performance parameters for a completely new trailer boat, ride and stability were high on Barlow’s list. With the 650 Pro Dive, he got both in spades – the fact that it is also a dry runner is a welcome bonus.

If the Pro Dive Series is any indication, Offshore Boats NZ will quickly gain a following among serious offshore trailer boat enthusiasts, and like them, Boating NZ looks forward to sampling centre-console and hardtop versions as they become available.