- describing a cruising motor dinghy

As I have got older I have got stiffer, so I have given up trying to fold myself into the usual dinghy boom tent, cluttered as it is with thwarts, centreboard and other sailing gear. This has restricted me to day sailing. It wouldn't matter if I was content with this, but it is the marine environment and its wild life that I enjoy, and I have found myself missing the nights spent in lonely creeks. However I remembered that when Uffa Fox began to feel his advancing age, he went to his drawing board and designed himself a motor boat which he dubbed 'Ankle Deep'; a fast shallow draught launch in which he could revisit the creeks and estuaries of the Solent.

As I come from an engineering background and have no prejudice against engines, I began to consider the characteristics that I would need in a powered cruising dinghy that would also be used throughout the winter for bird watching and beachcombing. While I like building boats, I was unable to find a design that suited my requirements. I didn't require a speed boat but I did want a boat that could exceed displacement speed. I will not bore you with the tale of my search but merely list the attributes of the one I finally found, the Orkney Coastliner, a 14 foot open boat designed for sea anglers.

APPEARANCE

While I was prepared to make allowances where appearance is concerned I didn't have to. She has a traditional shape of simulated clinker with a good conventional sheer. She has a wider transom than a displacement hull but not excessively so. When you are in a motor boat, the crews of sailing boats normally ignore you, but the Orkney must seem to be a friendly sort of vessel as I get almost as many salutes as when I am in a sailing dinghy. One member says that with the DCA burgee at the bow I look like the harbour master's launch coming along. Maybe they are worried I am going to ask for dues?

INTERIOR

The interior is roomy and uncluttered. The sole is level due to a double bottom, with a non-slip surface. This is somewhat abrasive as it is meant for the impact of fishermen's boots and I normally sail barefoot, but I take a roll of thin kitchen carpet with me; a comfortable addition I first noted in a past DCA President's dinghy. When I first saw one of these boats it was at its builders, the centre thwart with its integral locker was yet to be fitted. As this is not required for any structural reason I had my boat built without it. The result is incredibly roomy for a 14' 1" by 5' 7" hull and my sleeping bag looks quite lost in it. I wanted a maximum length of 15 feet, as I keep the boat in a standard garage with the engine permanently installed.

DRAFT

Its draft is only a few inches so good for exploring. However, although designed to plane it sports a keel similar in section to a Roamer's, which steadies it at anchor and keeps it running true when cruising.

ENGINE

It is powered by a four stroke outboard motor of 15 HP This choice of outboard was dictated by my requirements that the engine should be quiet and economical. As it is mostly used at moderate throttle openings, this rules out two-strokes as although they are quiet enough they are thirsty particularly at lower revs. A four-stroke can be expected to go virtually twice as far on a gallon of fuel and these are now available from at least three manufacturers. I chose Honda because of their experience in the field, reports in American magazines, the subtantial discount they were offering and the package deal I was able to negotiate with Orkneys! Although I am unlikely to need the capacity, a fuel weight equivalent to one other crew member would give her a 200+ nautical mile range. Other advantages are not having to premix the oil/fuel and the virtual lack of water pollution. Pollution from two strokes is much greater than many realise, as anyone who keeps a test/flushing tank for their engine will know. A big danger with small outboard powered boats is from following seas on the quarter when travelling slowly, or if the engine throttle is closed suddenly. Because of this my hull is designed for long shaft motors and has a self draining well just forward of the transom. As the boat is not intended to sail, the freeboard can be greater than for a sailing dinghy of the same length.

ROLLING

Rhythmical rolling is suppressed. The traditional displacement hull is bad in this respect and would have needed a steadying sail. However the semi-displacement or full planing hull is much better as it picks up dynamic stability at the higher speeds and its firm bilges resists rolling at other times. Also I have noticed when lying at anchor, that the lack of a mast means the often violent roll induced in wind over tide conditions does not occur to the same extent. The effect when lying in ones sleeping bag is of a quicker, rocking motion instead.

CONTROLS

Tiller steering is employed using the twist grip throttle. This allows responsive throttle control and steering in rough seas. Although essential for higher powered outboards, steering wheels and remote controls cannot compete and would take up some of the space which I find so appealing. Most of the time I sit to port on the rear corner thwart, with a cushion under me to soften the GRP. As I am sitting fairly high I have a good view but am somewhat vulnerable when the boat is being thrown about in a seaway. Under these circumstances I wear a lanyard attached to my wrist which is connected to the engine cut-out. If I were to go overboard the engine immediately stops. I shall eventually fit a grab handle to the gunwale on this side as well. When I am pottering about sightseeing I sit in the middle of the boat, on a low deckchair with a high back and use a tiller extension - unashamed luxury!

WEIGHT

The weight of hull with engine is about 450 lbs. Much lighter planing boats are available, but the extra weight of the Orkney gives an easier motion and the same advantage that a Roamer has of being able to ignore a small chop when working to windward. The craft is still relatively easy to handle on land.

PERFORMANCE

The performance is not too important but it does seem stupid to be limited to lower displacement speeds in view of the extended cruising areas that could be accessed by travelling faster. You can always travel slowly in a fast boat but not vice versa. The maximum speed is about 17 knots. Such a short boat tends to squat by the stern at lower planing speeds near 10 knots, but when I queried this the manufacturers recommended trim tabs in the shape of fins attached to the cavitation plate on the leg of the outboard. When fitted, the leg then resembles the tail of a whale or dolphin. Of American design and manufacture, they are a revelation. Since fitting them, the hull remains level at any speed obviating the nose up attitude at speeds below planing. Another advantage is the minimal wash now caused.

HULL SHAPE

The hull is designed so as to slam as little as possible in rough seas at moderate speeds. The normal choice of shape for planing boats is between the deep vee constant deadrise hull like most speedboats and RIB's used by the RNLI, and the warped bottom hull which is veed at the bow and twists out to a flatter run at the stem. The former gives a softer ride where the hull is driven at speeds which involve taking off over wave tops. However they are jiggly at anchor and inefficient in respect of the speed/power ratio. This doesn't matter for skiboats or the RNLI. They can always fit more powerful engines to gain the required performance. I am not interested in such speeds so the more efficient warped bottom is preferable. Modem thinking on motorboat bows concludes that the old chine bow that runs from the keel in a concave curve and ends in a sharp chine higher up makes for hard riding. It is preferable to have convex sections lower down and spray rails higher up to make the water break away from the hull before it reaches the gunwale. This is the Orkney's shape and the spray rails are formed by the simulated clinker skin.

SAFETY

I have a horror of needing to be rescued. Statistics show that most RNLI call outs are due to the casualty not having a second method of propulsions when the first fails. In fact the boat comes with galvanised rowlocks and sockets as standard, so with my Roamer's old oars I could claim to have the solution. However I do not intend my expeditions to be curtailed by any but the worst of weather, and under less benign conditions there is a limit to one person's ability to row against wind and waves; particularly in a boat not primarily designed for the purpose. She doesn't row as easily as a proper rowboat of course although she is the equal of most sailing dinghies; she has no mast to catch the wind but does have higher freeboard. Yet I still have the long shaft 4 HP engine that I used on my Roamer, so the problem of alternative propulsion is solved. I have belt, braces and skyhook!

A considerable amount of foam buoyancy is incorporated in the hull. It is designed to float level when flooded even with the engines fitted; then the inside water should just about reach thwart height. She has a double bottom and the cavity between can be drained should water enter through keelband screws or gelcoat fracture. Naturally I carry a second anchor and warp.

STORAGE

The craft comes as standard with a self-draining anchor well at the bow. Weighing anchor is a doddle -just drop it in on top of its warp. Any mud can go overboard the next time you anchor. Below this are two lockers. One is accessed from above thwart level which holds spare anchor, warps, fenders, buoyancy aid, waterproof clothing etc., and a lower one at sole height which will take water can, two-stroke fuel, bucket or WHY. There is also a lockable compartment at the stern which takes the fuel tank, spare fuel supply and tools.

WEATHER PROTECTION

As I much prefer an open boat I was not interested in the GRP cuddy that was available. Instead I have a folding canvas dodger. This gives good protection to most of the cockpit when heading into a chop, but little from rain. I have completed a framework for a tent which will give generous headroom but is yet to be completed. However I have spent two nights on board during the spell of good weather at the end of the season and it was a great pleasure to camp afloat again.

SUMMARY

Where rough water is concerned the Orkney obeys the same rules as any other small boat - it is strong enough and able enough to take more punishment than its crew. The extra speed means discomfort at times, but strangely one can often enjoy a smoother and dryer ride when one speeds up instead of slowing down. It all depends on the wave height, length and formation. I am still learning the more advanced skills of planing among the billows, but I progress with caution as I have seen a couple of nasty accidents due to speed in the wrong place. However I am beginning to suspect that small planing boats, properly designed and handled, can be more seaworthy size for size than traditional motorboats. In fact as I get most pleasure travelling at lower speeds; maximum power is used intermittently, when coping with rougher conditions.

Where does Odin's horse come in? Well, in old Norse, Sleipnir, the slippery one as she was known, was reputed to have eight legs and be capable of travelling over both land and sea - it seemed a good name for a boat that is trailed to the water, though inevitably she has come to be called Slippers - am I half way to 'fireside and slippers' then?