Blackdog Cat 550 SS

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Around five years ago, young engineer Luke Seuren was involved in setting up an engineering company in Whangarei.
He was a keen pig hunter and the company was named Blackdog Steelworks after one of his dogs. Luke is also a keen fisherman, and when it was decided to branch into building a range of aluminium catamarans, the name was a natural extension – Blackdog Cats. As Luke says with a smile, “Nobody ever forgets it!”
The company has been very successful in general engineering, employing 40 people, and so is their boat manufacturing branch, with the seven dedicated boat builders employed having turned out 80 hulls in three years of operation. The original design was a 4m cat, but the 4.5m hull is the current hot seller.
Such is the demand that Blackdog has recently appointed Marine North in Whangarei as their master agents, dealing with sales and fit-ups. This is so Blackdog can concentrate on construction, but they assure their customers that this arrangement will not mean any increase in pricing over their previous factory sales.
The hull I travelled up to Marsden Cove (near Whangarei) to test is a new model, the 550 SS. The 5.5-metre hull we were to trial is only the second Luke and his boys have made, with the first destined for an Australian buyer.

Heaps of buoyancy

This 5.5m boat has 4mm bottoms, and 3mm sides and topsides. The hulls have three frames supporting them on each side, in addition to the transom and forward ‘collision’ bulkhead. Each hull has three discrete buoyancy chambers, sealed and pressure tested at the factory, giving an excess of buoyancy over rig weight of 1400kg – exceptional for a boat of this length. The majority of the space under the sealed deck, between the hulls, is taken up by the baffled 120-litre under-floor tank, which is filled from an inlet on the port hull’s bow.
The welds looked well executed and had been left unground for maximum strength. Morgan Auto Painters in Whangarei had put a smart glossy-black paint job on the boat, as befits the hull’s marque.
The sealed tread-plate deck drains back to a sump centrally fitted under the transom (but easy to get at if any clearance of the 1000gph bilge pump is required). In fact, the pump does little more than empty the sump, as two 60mm scuppers with duckbills are also built in and handle any overflow.

Top cat

Cats are not such a common hull type in New Zealand as they once were. I have tested quite a few cats over the years and many suffered from similar problems, including: having ‘cat sneezes’ (caused when the descending hulls throw a blast of water forward, which is then whipped back in your face); ‘tunnel mist’ (a plume of atomised water that’s emitted from the gap between the hulls at the stern, after which the low-pressure area in the cockpit – formed by the boat’s forward motion – sucks this water into the boat); and often hammering unpleasantly into a head sea when the breastplate hits the water.
On the plus side, cats are stable, have big cockpit areas for their length and possess a lot of reserve buoyancy. However, with the exception of the extra space, pontoon hulls have many of these characteristics, too, and the trickiness of getting a cat design exactly right has led to the Kiwi aluminium-hull market being dominated by standard monohulls and pontoon designs.
So let me say now that Blackdog Cats appear to have got their hull design exactly right. There was no ‘cat sneeze’ or ‘tunnel mist’ evident, and once the hull was trimmed to the correct angle, it was a pleasure to drive.
After leaving Marsden Cove’s excellent facility, we headed out through the ‘Rip’ – the high current area at Whangarei Heads – and out towards the Three Mile Reef. The chop was a steep half to three-quarters of a metre in places, but the cat ate it up and spat it out; a very soft lander with no hammering in a head sea and a dry hull. The 550 SS does have the usual cat characteristic of leaning out on the corners – the opposite to a monohull – which some people find a little disconcerting at first, but you quickly become accustomed to this.
The test boat was powered by a Suzuki 140hp four-stroke outboard with a 21” pitch propeller and fitted with a custom-made hydrofoil for improved performance. This is right in the middle of the recommended 115-200hp power range. With two on board and a full tank of gas, running into a 10-15 knot head wind and moderate current, the rig produced 58.7kph (31.7 knots) at 5900rpm. These revs are in the middle of the peak operating range of 5,600-6,200rpm, indicating a good engine/prop match.

Open door policy

The cat was set up with a Quick capstan set on its side up in the bows to pull the warp into a half-height locker in the bow. This was specified by the customer, but to my eye there was not enough fall to make it work well (although the warp and chain could be pulled into a fish bin further back.) Luke had been keen to fit a Stress-Free (drum) winch – there is space for one – and having used them on a number of boats, I think this would be a good choice.
Access up into the bow section is achieved by folding down the central section of the windscreen, then opening the door to the side.

Stowage space and new technology

Opening the central door in the windscreen allows access to a couple of storage areas in the bow. Adding to this is a ‘glovebox’ compartment on the passenger side (plus grabrail) and access ports into full-length side shelving on both sides of the hull. Foot rests for helm and passenger seats also act as barriers to stop items stowed in front of them from sliding back into the legs of the crew when underway.
Seating consists of two upholstered seats on swivelling, sliding bases. They are very comfortable and feature roll-back bolsters that provide more room in front of the seats should you decide to travel standing up. The pedestal boxes have some internal stowage space as well.
A low ‘screen is complemented by a bimini top overhead, this last unit being hinged to fold down into the cockpit. The screen and foredeck design do an efficient job of deflecting much of the windrush when travelling, and the new owner intends to fit clears between ‘screen and bimini for more protection from the elements when required. Needless to say, the all-round visibility was pretty good when seated. I personally found the bimini a bit low to stand under when travelling, but this height had been customised to the new owner’s requirements.
Engine instrumentation was taken care of by a Garmin GMI 10 unit, complemented by a Garmin VHF 100i radio. A large blank section in the dash awaited the arrival of a new 12” model Garmin touch-screen sounder/GPS.
As mentioned, the broad sealed chequerplate decks drain back to a sump under the transom, which is fitted with a bilge pump and backed up by a pair of duck-bill scuppers. Each stern corner is fitted with a clever fold-down seat with Deck-Tread panel, which disclose access to stern lockers. One of these has the battery fitted inside a protective box. Ultimately the owner intends to fit one of the latest lithium-iron batteries.
Over the transom are two boarding platforms, both topped with Deck-Tread panels and one featuring a fold-down ‘T’ boarding ladder with tread-plate steps. Mounting plates for transducers are fitted on each hull.

Pluses for anglers

Cats have some great advantages for anglers, and the Blackdog Cat 550SS is no exception. Stability is one big one, allowing comfortable stand-up and walk-around fishing, even in sloppy conditions. This is added to with good mid-thigh support from the gunwale faces, and a toe recess aids balance. The tread-plate decking offers non-slip footing, too.
A second plus for cats is the extra cockpit room this configuration allows. Not many 5.5m hulls can boast a 2.35m beam. This provides plenty of work space, and Backdog has added to this by engineering space in the transom to take a 90-litre Icey-Tek bin, tucked out of the way. A six-position rocket-launcher is fitted on the bimini top, and three through-gunwale rod-holders are fitted along each side.
A smart combination plumbed live-bait tank (which looks to take about 30 mackerel comfortably) and bait-station is fitted to the transom. Four bolts make it removable and it features two more rod-holders, a viewing window (cleverly cut as the company logo), split cutting-board/tank lid, knife slots, sinker tray and overboard drain. A wash-down hose is to be fitted into the plumbing system.
A great setup for a day fishing boat and useful for divers too, with boarding ladder and platforms, and side shelves that look wide enough to take dive tanks.

Drive on, drive off

Blackdog makes its own trailers. The one the 550 SS was carried on was a gusseted, galvanized-steel A-frame with tandem axles and dual zinc-protected leaf-spring suspension. The rims and wheel guards were also galvanised, and hydraulic brakes work on the front axle.
Designed specifically for this cat, the trailer features two tilting rear rollers on each side and internal guide rails for the tunnel. The hull was easily driven on and off the trailer. Other features included a wind-down jockey wheel, dual-ratio manual winch, and submersible Hella lights. Tow weight for the rig is around 1400kg, fully fuelled.

A great rig

Stable, solidly constructed, smart-looking, and comfortable when underway, Blackdog has avoided the problems of some other cat designs. A great little fishing (and diving) rig, this hull provides a lot of fishing room (for the hull length) in the beamy cockpit and has the added safety benefits of a large amount of reserve buoyancy. What’s not to like?

Specifications

Material: aluminium
Configuration: catamaran
LOA: 5.5m
Beam: 2.35m
Bottom: 4mm
Sides and topsides: 3mm
Recommended HP: 115-200hp
Test engine: Suzuki 140hp
Four-Stroke
Prop: 21” pitch
Fuel: 120 litres
Trailer: Blackdog
Tow weight: 1400kg approx
Basic turn-key: $49,990.00
(115hp Yamaha Saltwater series)
Price as tested: $68,990.00
 

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