Supercat Sliver 29 — A 29ft craft by Supercat Marine

Tested by Erwin Bursik (November/December 2007)

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THE revolutionary 38ft Supercat — Stilleto — which I reviewed in SKI-BOAT March/April 2001, has proved very popular in the marketplace both in South Africa as well as the Seychelles, Madagascar, Kenya and Moçambique. One has even been shipped to the United Kingdom. Number 15 off the production line, destined for Cape Town, was moored next to the 29ft Sliver which I had travelled to Port Alfred to review. She was all ready for delivery the following week, but I still got a little bit of time to play with her …

However, it was Sliver, a new generation craft which has appeared in recent Supercat adverts in SKI-BOAT, that I had raced down to Port Alfred to review ahead of a series of cold fronts that were rumbling up from the Cape. was predicting winds over 40 knots from the south-west, and I knew that a few hours of wind of that magnitude would effectively cancel any plans we might have of exiting the notorious Kowie River mouth.

Having arrived later than expected due to mechanical problems on the car I had hired at East London Airport, I had only a few hours of daylight in which to take the 29ft Sliver to sea before the darkness and ahead of the south-westerly due at midnight.

Mooring lines were cast off, and with Dennis Schultz’s son, Clinton, at the helm, we went down the river, through the piers and out into an ugly sea. Manoeuvring through this “interesting” bar with a big easterly swell and a pushing spring tide brought back memories of when I first took this boat’s big sister to sea. The words I penned after that trip were as true on the day I went to sea in the Sliver as they were after my trip on the 38ft Stiletto …

“And, yes, it was very interesting indeed as the 11m craft approached the mouth. There was no way to turn in a hurry — in fact, there was no way we could turn at all with the sandbank that was hugging the east pier. It was either take it on the bow or reverse out of trouble — and pray that a big set wouldn’t turn us side-on.

“Interesting, very interesting … ‘Keep her straight,’ Dennis instructed. ‘Don’t use speed, the hull will do the work.’ Well … it’s not so easy when a two-metre-plus wave is bearing down on you, followed by a few bigger ones.

“I watched dry-mouthed as the long forward sponsons were enveloped by churning white water. I kept the throttles at half power as the wave boiled past us, the water running off the rounded sponsons as they surfaced. Strange — the craft didn’t seem to reach for the sky which is what would happen with a ski-boat, and we were moving forward to meet the already curling backline.

“I wanted to jam the throttles forward, but Dennis talked me out of it. The backline loomed and the sponson cut into it, and — without a jolt — we were through the worst! Only then was I allowed to increase speed.

“What an experience — and we did it twice more that day just to relive it and get the adrenaline flowing!”

Again I marvelled at the way the displacement hulls with their incredibly fine, almost knife-like entry enable a craft to pierce through these big waves and proceed forward at relatively slow speeds. And this is done without the slamming, jumping and ploughing one would experience on any conventional ski-boat of this size, let alone the drenching one would receive.

For those who haven’t read about Dennis’s displacement hulls as opposed to the conventional planing hulls that we are so conversant with in offshore boating, here’s a brief overview: A displacement hull is designed to float in the water — like an ocean liner — at a certain waterline level and then use its power source to push it through the water, retaining that waterline level. A planing hull, however, is designed to float at a certain depth in the water when stationary or at very low speeds; then, using a good deal of power, be thrust forward until the craft’s hull is virtually out of the water and skimming over its surface. High-powered motors are required to maintain sufficient power to keep a planing hull moving forward and also keep most of her out of the water.

To illustrate the difference, Sliver was powered by twin 40hp Yamaha four-stroke motors which, at top speed, provided 21 knots SOG. I believe it’s fair to say any planing catamaran of this size and weight would require twin motors of at least 150hp to obtain the same performance.

With the theory behind us, it was time to see how the 29ft Supercat Sliver performed in practice in the big north-easterly sea whose top was being blown off by the ever-increasing north-westerly wind of about 15 knots that preceeded the big blow that was expected out of the west.

As soon as we exited the Kowie River mouth I took over the helm of Sliver to enable me to maximise the time I was to have on the ocean. The sun was already closing in on the western horizon and I had no intention of trying to ride back through the piers in the dark.

Easing the throttles forward, I set a course into the prevailing wind and watched as the Navman GPS/sonar reflected her speed climbing effortlessly. Remember that the speed on a displacement hull is an even increase between power and forward momentum. Initially I fell into the trap of thinking that the apparent speed did not correlate with the speed my instrumentation was showing.

She travels so smoothly that the speed is deceptive. As a result, I kept looking back at where the water exited the tunnel to appreciate the speed at which we were actually slicing our way through the water.

At 2 000rpm into the wind we were registering 8 knots, at 3 000rpm we were doing 13 knots, at 3 800rpm — 17 knots, and at 4 500rpm — 21 knots.

I opened the throttles completely, but we seemed to have reached the upper limit of her power because the rpm didn’t increase much more and the speed settled at 21 knots. Dennis explained the reason for this, but it was far too complex for me to fully comprehend. I settled for a speed of around 17 knots with the motors cruising at 3 800rpm for my long run into the wind, but with a big following easterly swell which gave an extremely soft and dry ride.

Initially I once again had to get used to the craft’s bows being low in the water as opposed to a planing craft’s bow-up stance, and I tried to lift her bows with the motor trim. Dennis just smiled. He had already told me that trim has a negative effect on these hulls. “That’s why I paint the waterline on my boats,” he said, “so that skippers can see how she should ride once she’s loaded, to get maximum performance.” What he meant to say was that it’s for idiots like me who don’t believe in the theory behind displacement hulls.

I quickly learnt that as I tried to raise her bows the speed dropped astoundingly quickly, even though I had retained the same throttle settings. There was also a dramatic increase of hydraulic action at the stern of the craft as the water through the tunnel — normally very clear — was being impeded, thus causing not only drag, but also some jarring.

Thus I quickly returned her to an even keel and retained it that way for the rest of the review.

After a long run to the west I slowed down considerably to see how she would perform at various trolling speeds. Having previously watched one of the 38-footers, Castle Lager, which has been fishing off Watamu, Kenya, for five or six years, especially the way that craft trolls and the fish it catches, I was in a position to compare the 29ft Sliver with a known base. Another benefit of the displacement hulls is that she trolls at a very even speed through the water with little or no reaction to wave action, be it head-on or with a following sea.

To attain the 5-6 knots required for skipping baits for sailfish or trolling deep-diving lures, the two little 40hp motors were idling along at just over 1 000rpm and producing almost no wake. Even with the relatively big wind-over-swell chop I was experiencing, she trolled effortlessly side-on to the sea, and minimal spray was thrown over the helm station area.

Clears are available but had not been fitted for the review. If fitted, they would protect the entire saloon area in inclement weather.

At idle,very slow and at livebait or ’cuda bait troll speed she again held course relatively well, but both motors had to be running, otherwise the wind interfered with the troll patterns I had selected. In a fairly calm sea I am sure that trolling with one motor would be practical as well as productive.

Two other aspects I must mention are, firstly, the stable way she drifted in that lousy sea; and secondly, on one 40hp motor she comfortably achieved a 10 knot SOG, which she retained for a considerable distance while not putting the motor under undue stress.

The run back towards Port Alfred was uneventful as I had wind from the stern and a head swell, so apart from ensuring a comfortable ride I had nothing to prove. Unfortunately in the prevailing conditions I wasn’t able to test her reaction to a big following sea other than by following some biggish swells back into the river. Sliver held her speed running back between the swells, and we were able to hold her bow over the cresting wave to give us maximum water depth as we crossed the shallow sandbar.

Before I attempt to describe this unique craft, I must mention that Dennis made it clear that she was designed for a cruising/fishing application and not as a dedicated fishing machine. As her big sister has proved, she will thus be ideal for use in tropical waters where her ability to “play and fish” around the islands can be put to great use. Another benefit of these hulls is that they can even steam up to a sandbank so that those aboard would barely get their knees wet while disembarking.

When it comes to her construction, the 29ft cat is manufactured in a unique manner in so far as boat construction in South Africa goes. Each hull is moulded in two halves, and then these are bonded together like a clamshell, as opposed to laminating the entire hull in one form. To put it simply, the two inner-half hulls and the deck bridge are moulded and rigged out with all the extras, and then the outer hull sides are bonded on. We don’t have space — or the technical knowledge — to properly convey the intricacies of this process as well as the pros and few cons of it, but suffice it to say that it works — and works well.

The designs for the helm station area and the aft fish deck were based on the now proven design of the 38ft Supercat, as well as the experiences of the Shultz family during the month-long liveaboard cruise they undertook on that model up the Moçambique coast. This has resulted in a user-friendly deck layout which also encourages crew to be ensconsed in the right areas when travelling to ensure that the weight distribution — whether there are three crew members or six — will result in the Supercat 29 riding to her designed waterline level.

This is achieved by means of a large horseshoe-configuration seating arrangement in the helm station/saloon area that centres around a freestanding helm station. The skipper’s domain is simple, yet stylish. From a seated position in an extremely comfortable chair, he has all the controls at his fingertips and can easily view the instrumentation both on the control panel as well as the Navman sonar/GPS and radio, mounted on a plinth built into the Targa-style T-top. This T-top becomes the saloon roof when the clears are fitted.

Aft of this area and a step down is the wide fishing deck that extends a good way aft on the sponsons to a position that will allow an angler to swim a hooked fish past the motors with relative ease. The area has reasonably high gunnels and an additional protective stainless-steel rail for extra safety while cruising.

Apart from access steps to the motor wells, a full transom stretches across the rear of the craft, and a full array of rod holders can be fitted here.

A good-sized fish hatch, as well as a pair of Luna tubes, are positioned on the deck, while the livebait hatches are situated right aft in the motor wells.

The bunking area and toilet are situated in the two sponsons and below the saloon deck. Access to this area is via two Lumar-style waterproof hatches on the top of each hull.

Access in or out of here is relatively easy, even for a big guy, but I might add it is only for use when one is really tired.

Upfront a trampoline-styled foredeck that is stretched remarkably tight provides not only a sunbed for the ladies, but also the ideal position for casting and working a fly.

Having worked with Dennis for the last 25 years, I’ve come to know that his attention to detail and the quality of finish is exemplary. Dennis’s two sons, Neil and Clinton, have now taken over the day-to-day running of the factory, leaving “the old man” to his passion of innovation and building his dream boat, a 67ft Supercat of the same design. Thankfully, Neil and Clinton have followed closely in their father’s footsteps and would rather strive for perfection than take short cuts for the sake of a few rands.

The craft’s finishes, from the stainless-steel eyelets that hold the trampoline to the lockable hatch covers, need to be seen to be appreciated.

In conclusion, this 29ft cruising-cum–fishing craft motors on the smell of an oil rag — we used less than ten litres of fuel in over four hours of boating — and comes in at a price that you’d pay for many of the 24-26ft ski-boats on the market today.

Indeed, this is a boat well worth considering. For fishing, pleasure boating and extremely comfortable riding at sea, this craft could be just what you are looking for.

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