Is it a boat? Is it a car? No, it’s … err, both! Well, almost. Or not…
Ever since man first figured out how to initiate internal combustion, he has attempted to devise vehicles that can travel on both land and water. And as a result, there have been many spectacular failures along the way. The sea floor is littered with the hopes and efforts of heroic, though flawed, individuals who claimed to have invented the ultimate car/boat hybrid. Many of them have taken the form of existing cars, redesigned and modified by well-meaning amateurs, that have been ‘waterproofed’ and given some form of propulsion that allowed them to move through water. Typically though, they have exhibited attributes more akin to submarines than boats. Overwhelmingly, the most successful amphibious vehicles have been those designed for military use and a quick search on the Web will uncover all manner of armoured craft designed to move stealthily across water and land.
But in recent times, a Kiwi company has attracted international attention with an ingenious creation that successfully solves the age-old dilemma of amphibiousness. Auckland-based Sealegs International has refined the concept by fundamentally merging RIB (Rigid Inflatable Boat) technology and design with its own foldaway, three-wheel drive system. The result is a boat that can be driven to the water and, within limitations, can be used as a relatively versatile all-rounder once out on the briny.
I became acquainted with Sealegs when we arranged to meet its Australian representative – and now Sealegs director – Will Burrell. Burrell became involved in the company after being impressed when he bought two of its craft a couple of years ago. He has a waterside property on the southern shores of Port Phillip Bay and his situation turns out to be ideal for demonstrating the advantages of the Sealegs concept. As Burrell tells it, there are a variety of lifestyle scenarios that lend themselves to Sealegs ownership. If you live within walking distance of the water, have to launch over difficult terrain, don’t have access to a boat ramp, require a quick-launching craft for emergency situations, are looking for a luxury boat tender or simply can’t be bothered with the hassles of launching a conventional trailer boat, then a Sealegs might be for you.
Sealegs currently offers three models: the 6.1m RIB we tested, a 7m version currently gaining popularity in Europe and a 6.1m all-aluminium hulled version called the D-Tube. Each employs fundamentally the same land-based drive method. Hydraulic pressure is used to drive the wheels as well as to lower and retract them. A compact, 16hp, air-cooled Honda stationary engine, situated underneath the skipper’s seat console, powers the hydraulics. Drive is provided by the two rear wheels, while the front is for steering. Top speed on land is 10km/h.
SIMPLE AND SMOOTH
The main thing that struck me about the Sealegs was the simplicity and smoothness of its transition from ‘land crawler’ to boat, and back. For our demonstration, we met up with Burrell at the Blairgowrie Marina on the Mornington Peninsula, south of Melbourne. He had trailered his Sealegs to the marina, where we watched as he ‘drove’ it off the trailer. This exercise involved simply starting up the Honda engine to power the hydraulics, then, using levers attached to the console, lowering the wheels, which are connected to the RIB by folding legs, and reversing off the trailer. Later in the day, Burrell demonstrated how equally easy it was to drive it back onto the trailer – both exercises performed easily by one person.
Once he’d backed it off the trailer, it was simply a matter of driving it to the water. While there was a ramp nearby, Burrell chose to demonstrate Sealegs’ all-terrain capabilities by traversing the nearby scrub and beach. Here, another unique capability of the Sealegs became obvious. Since we were standing on the sand, it was a bit of a reach to climb aboard with the wheels deployed. Burrell simply raised the front wheel, tipping the bow until it was low enough to step in. As Burrell commented, climbing aboard was much like mounting a camel. Like so much else about the Sealegs, it was easy, clever and simple.
The wheels are lowered and raised by a pair of rocker switches on the port side of the centre console, while a small joystick is used to drive forward or backward using hydraulic pressure provided by the Honda engine.
While visually, the Sealegs has a praying mantis-like, almost clumsy appearance in land-mode, it certainly has no trouble moving over typical beachside terrain. Burrell demonstrated its dexterity by driving over small sand humps, tussock mounds and through shallow water, the Sealegs taking everything in its stride. As far as its terrestrial agility goes, it was certainly convincing and had no trouble handling soft or wet sand. But it does have its limits, and is not designed to be driven on normal roads. Nor is it legally registerable for road use, although it can be trailered, as demonstrated by Burrell.
TAKING A DIP
With a blustery 15-20 knot northerly facing us, it was time to put the Sealegs’ on-water behaviour to the test.
Initially, Burrell took the helm and slowly drove into the chop. As the water became deeper, he lowered and started the Yamaha 130hp motor, leaving it to idle in gear. Then, as we got to around a metre in depth, he slowly raised the wheels, at the same time easing the throttle forward on the outboard and shutting down the hydraulic engine. Then away we went, the rear wheels tucked well out of the water, while the front rode high at the bow. Fully retracted, none of the wheels are in the water, ensuring they generate no drag while underway.
Now, for all intents and purposes, we were in a boat, or RIB to be exact. The chop gave us a chance to assess the Sealegs’ performance, ride and handling in less-than-ideal circumstances and I have to say that, given the fact that it is a RIB, I was fairly impressed. The hull is constructed from sturdy 4mm aluminium and, with a deadrise of 21 degrees, it provided a comfortably soft ride and demonstrated good turning ability. It was also relatively dry and stable and, given the brief time we had aboard, I’d have to say it would be an adequate platform for a variety of activities, from fishing to water sports and utility transport. Certainly, from a performance point of view, the 130hp powerplant ensured spirited acceleration and, according to Burrell, would be good for close to 60km/h top speed. Conditions on the day weren’t exactly conducive to testing it out, but I’ve no doubt the combination of 6.1m RIB and big engine would be good for it. Base power is rated at 90hp, giving a speed of around 55km/h, according to Sealegs.
There is plenty of under-seat and under-floor storage available, giving the Sealegs even more versatility and enough seating to cater for up to five adults or a maximum payload of 500kg. Given its relatively low freeboard, hand-holds are well distributed around the craft and were certainly appreciated on the day. A combination ski pole/rod holder on the transom keeps the options open once out on the water, and owners should be able to get a day’s running out of the 80-litre fuel tank. The deck is self-draining, backed up by a 4180lt/hour bilge pump, fitted as standard.
Returning to shore, Burrell simply slowed and lowered the wheels again as we came into the shallows. While still maintaining forward momentum with the outboard, he waited until the wheels had achieved solid traction on the bottom before shutting down the engine and retracting it. Then, we simply drove back onto dry land. Burrell gave me the opportunity to try out the controls and complete the transition myself and, once I’d gained some familiarity with the switches and throttle/gear system, I have to say the whole procedure was relatively straightforward and easy to master. I’d be interested to see how it went in an ocean surf situation, particularly when returning to land with some big waves up the rear. I’d hazard a guess that you’d need to keep your wits about you as you went through the transition from prop to wheel power. Nevertheless, the system proved itself as we went from land to water and back a number of times during the day.
From an engineering point of view, Sealegs claims its drive system is more than up to the task of moving the close to 900kg (dry) craft around on land and resisting the rigours of saltwater emersion at sea. Certainly, external appearances would suggest the drive and support hardware for the three wheels is robust and solid enough, and the specs show each wheel assembly is rated to handle two tonnes. Everything is made from either stainless steel or alloy, so corrosion shouldn’t be a problem.
Sealegs has reportedly already found a strong following in its native NZ and much further afield. Burrell reported that Italian rescue authorities opted to purchase a number of craft earlier this year, and, at the 2007 Southampton Boat Show in the UK, the company took orders for 15 boats. Sealegs is listed on the NZ stock exchange and recently received an NZ innovation award in which judges commented that it was “of extraordinary high quality, extremely well researched, financed and marketed.”
Having put it through its paces, I have no reason to think the concept won’t find favour with Australian boaters whose circumstances lend themselves to an amphibious craft that can be easily launched and retrieved without benefit of a boat ramp or trailer. But even then, as demonstrated by Burrell, it can be trailered and driven on and off with ease, adding to its versatility.
Base cost for the 6.1m craft we tested is $59,000, with engine and trailer extra. Our test boat was fitted with a number of options, including the ski bar/rod holder, Navman electronics, 130hp Yamaha and upgraded helm seat, which boosted its price to around $92,500, including trailer.
For more information, tel 1300 SEALEGS or go to: www.sealegs.co.nz.
SPECIFICATIONS: SEALEGS 6.1
Length: 6.1m (with wheels retracted)
Hull deadrise: 21 degrees
Engine: Std rating 90hp, test 130hp Yamaha
Price: From $59,000 (plus engine and trailer)