Deltacraft Islander Club


Powercraft's BOATS OF THE YEAR

Is this the Answer.

IT was in the March issue of POWERCRAFT that we tested the non-trailerable version of the Delta Islander Mark II. In that test we made a passing reference to an alternative version of the boat, a water-ballasted trailerable type, which manufacturer Steve Leonard forecast would probably be the most popular of the two after an initial period of establishment.

We described that first boat as the "nuclear age answer to the traditional family launch". In retrospect, that may have been too fulsome a description. By our estimation, the trailerable version comes closer to solving the boating problems of the average Australian family than any vessel we've yet tested.

The emphasis is on the word "average".

Certainly, there is a percentage of the population who are able to afford big cruisers, just as there is a percentage who want nothing but V8 powered ski boats. We don't consider them to be "average".

But in the past, those people who wanted to get out on the water with their families at modest cost - both in terms of initial outlay and day-to-day running expenses - and in displacement-boat comfort, has been pretty much ignored.

Those people, many of them looking for a small, but comfortable and economical displacement cabin cruiser have had to do without or compromise and run their hard-chined planing hulled boats at sub-planing speeds. Anyone with even a passing knowledge of boat design that this is false economy.

The answer obviously, is a displacement launch, powered by a small diesel motor, with the added flexibility of being trailerable behind the family car.

The new Deltacraft Islander fits that description to a "tee".

It is capable of sleeping four or five people, has an efficient round-bilged displacement hull, and is powered by an economical marine diesel. Fully fitted it costs around $20,000.

The key to its success is its water ballast system, which assists stability without an on-trailer weight penalty. Indeed, all-up weight on the trailer is 1100kg (as tested), well within the towing capability of a Falcon or Commodore.

Manufacturer, Steve Leonard of Galecraft, told us that from the beginning of the project, Galecraft have strived to create a genuine live-aboard vessel within length limits governed by sea-keeping, comfort, efficiency and cost. Its heritage as a firm round bilge, heavy displacement work launch ensured superior sea-keeping and stability. The development of a self-draining cockpit with the diesel located entirely under the floor and provision of full headroom throughout the cabin and shower-toilet enclosure, makes the Islander a uniquely quiet and comfortable craft, overcoming the disadvantages of the traditional half cabin.

The trailerable version tested has floodable ballast tanks. Water enters the staggered scoops in the keel, flooding strategically placed tanks in and above the keel. A vent pipe is uncapped at the foot of the helm position to allow displaced air to escape or enter when launching or retrieving.

The hull has what could be called a "tadpole" shape, used successfully on low-speed bulk ore carriers designed 25-30 years ago. At lower than hull speeds (particularly small boats), these hulls are remarkably efficient. The bluff bows push the water aside, around the firm bilges amidships, and clear the rounded aft sections with minimal drag.

On smaller hulls, the firm bilges stiffen the hull's motion when beam-on to a swell, without the drag of chines.

The Islander Mk II's centre of buoyancy is ahead of the centre of gravity, creating good reserves of buoyancy forward. Combined with the relatively small transom area, the design ensures good tracking, with little fear of pitchpoling in a big following sea, one of the main areas of weakness in most transom sterned powerboats.

A long skeg, starting at the forefoot and running aft to protect stern gear, gives good directional stability.

External layout

The external arrangement has a self-draining foredeck and cockpit with a non-skid surface moulded in to all working areas. The foredeck has a moulded ground tackle and rope storage bin, which should have a cover to increase working area on the foredeck. A bow roller, with retractable locking pin, and cross bollard, are mounted ahead of the bin.

The bollard should be larger; it would only be adequate on a four metre runabout.

A bow rail and teak grab rails assist in working forward and moving aft on the side decks and a grab rail on the hardtop would be useful.

An aft hinged hatch, strutted for various opening heights, is fitted to the forward end of the cabin, enabling very easy access to the foredeck from the cabin, and assisting airflow.

Self-draining storage pockets flank the cockpit on either side, and these are useful for oars, rowlocks and assorted ropes for a tender, or rods and fishing tackle.

Protection for the cockpit is provided by a GRP windscreen incorporating five mm armour-plate glass. Wiring for the riding light on the hardtop, and wiper over the helm position is carried down through a moulded channel in the forward inside edge of the screen. How nice it is to have a windscreen wiper on a boat of this size.

The test boat had the optional GRP hardtop, giving 1.9m headroom, and a mounting for roll-down side and rear curtains, effectively creating a weatherproof living area.

Flush inspection hatches for the steering gear and engine provide access to these areas, the former drained by channels leading to the cockpit drains. The latter has lead soundproofing, substantially reducing engine noise underway.

Cabin layout

The cabin is separated from the cockpit by a full bulkhead and central companionway and, the toilet door doubles as cabin door when used with a forward hinged L-shaped flap above it. An overlap between these assists airflow.

The cabin has standing headroom throughout (max 1.86m), and cruising accommodation for four to five people. A dinette for four converts to a double bed, with a single settee berth to port. The two cockpit benches each form a berth.

The dinette table maybe used in the cockpit when fitted to the inboard transom bracket and six adults fitted there comfortably during the test. In fact, at no time did she feel cramped with eight aboard. The galley is L-shaped, with a deep sink and shelves under with a teak veneered door. A two-burner stove was fitted to the bench top, which had a small moulded lip. Unfortunately there was very little room left for food preparation.

A 12 volt Engel refrigerator, adequate for a weekend excursion for four people, was mounted above the standard "pots and pans" cupboard.

Opposite the galley is a fully-enclosed toilet compartment with flushing marine toilet and further storage space. The test boat was designed for Lake Eildon in Victoria, and had an optional 70 litre holding tank under the dinette area. Apparently the Islander 5.7 is the only boat of her size to have this option.

The toilet compartment had an optional pressurised shower system ($150), working off engine heat. The 48 litre tank will provide 11 three-minute showers. This area also has full headroom, and is a wonderful rarity on boats of this size.

Bunk cushions and backrests were upholstered in a hard-wearing woven fabric and there are storage bins under and adjacent to each berth (the latter lined with carpet). Shelves with teak fiddles are provided behind each berth.

Fluorescent lights in the cabin and toilet compartments draw one amp/hr each.

All fastenings used in outfitting are apparently stainless steel or marine aluminium and all exposed surfaces, whether fibreglass, fabric or timber, have a serviceable low maintenance finish.

Performance, handling

The test boat had the optional three-cylinder Yanmar 3GMD lightweight diesel installed, which seemed to be smoother than many four-cylinder diesels I've tested, particularly above idle. Certainly, with the effective soundproofing, provided the boat was one of the quietest diesel cruisers of any size I've been on.

Accessibility to dipsticks (engine and gearbox), injectors, filters, battery and stern gland was very good.

The motor started instantaneously hot or cold, and acceleration ahead and astern (far better than expected) were excellent, considering the engine was over-propped.

Over-propping can be likened to driving a car in overdrive up a steep hill, although the fluid qualities of water prevent overloading to some extent.

A diesel engine likes working under load, and were the engine to be fitted with a prop which would allow it to reach its designed peak rpm, at 2000rpm it would only be running at one third of its designed load, or potential power. Coupled with direct raw water cooling, this practise would be detrimental to the engine over a prolonged period.

Steve Leonard examined the normal cruising rpm most owners would use - around 2000, he reckons - and fitted a prop capable of keeping a reasonable load on the engine. Therefore, although the engine develops its power at a theoretical peak rpm of 3600, 3000 was chosen as the maximum effective rpm before overloading would result.

Over a measured distance, powering through a steep cobblestone chop with a load of eight people aboard (six in the cockpit), we averaged 6.9 knots. With a light load, better trim, and calm water, 71/2 to eight knots may be possible. The engine had only 40 minutes on it, and Ron Cross from Western Fuelpump and Injector Services, the Yanmar distributors, who came along for the day, believed it would take 100 hours before the engine was fully run in. Although this may not seem fast, reducing the revs to 2000 still gave an effortless five knots, with virtually no vibration, and certainly very little noise.

The lack of vibration is due at least in part, to the four-bladed 350mm prop. On a normal three-bladed prop, one blade is always in the "shadow" of the skeg or stern post which thus creates an uneven beat and as a consequence, vibration. With a four-bladed prop, the coverage and exposure is always balanced. Although two blades may be shadowed, two will be working in clear water and vibration is minimised. Besides, there was no other way of achieving a 75-80 per cent blade area on a three-bladed prop of 350mm diameter. Porter's did the basic casting, and Galecraft modified it to suit their requirements.

Exhaust noise was another problem, although somewhat lessened with a three-cylinder engine. There is a detonation every 120 deg rather than every 180 deg; quite a difference. It was found that by attaching a 0.5m exhaust hose to the outside of the transom outlet, the noise would be buried in the stern wash. Back pressure is minimal, the exhaust doesn't splutter all over you when working on the stern platform, and a scavenging effect when running ahead acts like a semi-extractor, helping the engine to breathe more efficiently. Not far removed from the idea of through-prop exhaust on most outboards. As mentioned earlier, vibration all but disappeared above idle. 2000-2500 was found to be the best rpm range, above which the hull began to squat.

Ron informed me that normal fuel consumption on this engine works out to be 1.3-1.81ph, depending on speed and load. Also, being under stressed, the engine should last a long time. Oddly enough even though the hull is finer aft than a semi-displacement or planing hull, we found weight aft, at rest or low speeds, had little affect on trim.

At rest we had eight people sitting on the cockpit benches, yet the drains were at least 50mm above the water. Only at peak revs, with six aft, did water start to lap through the drains. Handling at all speeds was impressive.

The long skeg assisted tracking, enabling "hands off" steering for several minutes at a time. The boat had an easy motion, giving the impression she was working with the sea rather than fighting it. She's not a particularly dry boat, but then no good seaboat is.

She appeared to be a stiff boat, the firm bilges reducing any tendency to start "pendulum" rolling. The only quirk was the tendency to hobby-horse or pitch easily in a head sea, the result of her wide beam-to-length ratio. A longer waterline on the same beam would have drastically reduced this problem.

Response to helm was excellent. Turning was achieved in two boat lengths to port, and 21/2 to starboard. The Islander would steer to port quite easily astern, but reluctantly to starboard - no doubt the reaction of the prop. "Three-point-turns" were achieved in either direction by using power ahead with the rudder hard over in the desired direction to kick the stern around.

Morse single cable "push-pull" steering was reasonably light and very direct and the small, "shippy" wheel could be spun rapidly when desired. A single lever throttle/ gear control had a positive and progressive feel. Controls were well positioned standing or sitting, and instruments easy to read. Vision at the helm when standing was excellent, although sitting left a little to be desired, as the seat was too low. However, a moulded footrest supported the feet.

On the trailer

Utilising the rope-on-the-quarter trick to hold her in line with the trailer, retrieving was easy. A five-to-one reduction on the trailer winch handle made winching up no more difficult than with a five metre runabout. All the weight of the hull is taken on the keel rollers, and the main weight in the hull is over the trailer wheels. With her deep skeg, immersing the trailer almost to the wheel tops is required.

All the water from the ballast tanks drains progressively and reasonably quickly as she is winched onto the trailer. Pulling her up the ramp with my two year- old VC six-cylinder Commodore station wagon proved easier than expected. For those who drive a Commodore, the vacuum gauge didn't drop into the acceleration zone, indicating the engine wasn't straining.

Towing was quite easy. Perhaps I am overly cautious, but I felt 40- 50kmh was the maximum I'd want to travel in built-up areas, simply because 1100kg is a fair load on the vehicle's braking system. Obviously 80kmh would be possible on a good highway, and a comfortable cruising speed, with windage preventing higher speeds. Automatic transmission is better than manual (apart from long downhill runs), as it allows the engine to work at the correct speed for the job at hand.

I do believe, however, unless one had a four-cylinder vehicle with a full chassis and low gearing, such as a utility, or four-wheel-drive that a normal four-cylinder car would be inadequate for the task. Still, one can always try.


The concept of this boat is exceptionally good.

Although initially skeptical of the water ballast idea, I can only say it works well. I've never seen so much room before in a 5.7m boat of any type and for a family who wants peace of mind and economical, relaxed cruising, but don't want long sea passages to reach distant cruising grounds, this is clearly the answer.

On the day of the test we had a couple on board who were interested in a boat of this type. At the end of the day, I saw a deposit cheque for $3000 from them in Steve Leonard's hand. We hope to do an extended coastal passage on her soon.

What we liked

Norton: The basic concept; enormous amount of room for length; easy motion in a sea; smooth, economical and quiet engine; access to all normal engine and stern gear service points; effective non-skid on working surfaces; high quality of mouldings; and emergency manual starting; and standard manual diaphragm bilge pump.

Tilbrook: Non-skid surface in cockpit and easy to get in and out of; lightweight fittings: easy for a woman/small man/child to move, e.g. table, engine hatch; zippered section in side curtain flaps comfortable and spacious bed for two persons in cabin; attractive fabric, normal conversation in cockpit at anything but peak revs; compact, easy to clean layout; safe, secure feeling.

What we disliked:

Norton: Tendency to pitch in head sea; inadequate deck fittings and insufficient grab rails.

Tilbrook: Storage for food, utensils inadequate; inadequate bench space for food preparation, and stove should have griller; overall lack of storage space for clothes etc.; combined toilet and shower facilities - concern for young children aboard about germs developing.