How to Choose a Dinghy and Outboard for Your Boat

The Boat You Use More Than the Yacht

Count the hours. A cruising boat at anchor moves perhaps every two or three days. The dinghy moves four, six, eight times a day: water, bread, the harbourmaster, the beach, the snorkel spot, the boat two hundred metres away that invited you for a drink. Over a five-month season that is comfortably three hundred landings, most of them short, most of them with a load, many of them on a surface that was not designed for landing on. The picnic to the cove three miles away happens once, maybe twice.

That ratio should decide the purchase. A tender optimised for the picnic is big, fast and heavy, and every one of the three hundred other trips pays for it: two people to lift it, a hoist for the engine, a bow that will not fit under the stern of the mother ship. A tender optimised for the daily run is light enough to drag up a beach alone, dry enough to arrive in town clothes, and tough enough to be left on rocks. It will be slow to the cove. You will not mind.

Rigid vs Inflatable, and the Hybrid That Won

A hard dinghy rows beautifully, takes a small sailing rig and lasts for decades. It is also unstable when a wet swimmer climbs over the side, scuffs the topsides of the yacht every time it lies alongside, and cannot be deflated when you want the deck back. Pure inflatables — the roll-up with slats or an air floor — stow anywhere and are almost impossible to capsize, but row badly, get you wet, and their soft floors are short-lived on coral and stone.

The RIB, a rigid V-hull with inflatable tubes, is the hybrid that took over cruising because it keeps the stability and the load carrying of an inflatable and adds a keel that tracks, planes and can be dragged up a beach. Its price is that it never gets smaller. If your boat has davits or a clear foredeck, buy a RIB. If it has neither, you are choosing between an air floor and living with a dinghy on the coachroof.

Between aluminium and fibreglass RIB hulls, aluminium is 10–20 kg lighter for the same length and shrugs off the rocky landings that crack glass. Fibreglass gives the softer ride in a chop and costs less. For a tender that will be lifted daily, the weight saving wins.

PVC vs Hypalon: the Sun Decides

Inflatable tubes are made of coated fabric, and the coating is the whole argument. PVC is cheaper, welded by machine, and perfectly good for a boat that spends most of its life under a cover in a northern climate. Hypalon — the DuPont trade name is retired and the material is now sold as CSM, chlorosulfonated polyethylene, often with a neoprene inner layer — costs roughly a third to two-thirds more, is glued by hand, and resists ultraviolet, heat, fuel and abrasion far better.

What that means in practice: a PVC dinghy left in Mediterranean or tropical sun all season can start to go sticky at the seams and chalky on the tubes in three to five years. A Hypalon tender in the same use commonly reaches ten to fifteen. Hypalon can also be repaired with a two-part glue and a patch in a way that holds; PVC field repairs are a gamble. If you cruise where the sun is strong, the extra cost is the cheapest insurance you will buy for the boat. If you sail summer weekends in Britain or the Baltic and keep the dinghy covered, PVC is a rational choice.

Sizing to the Crew, Not the Brochure

The published capacity of a dinghy is measured in flat water with everybody sitting still. Real trips involve a bag of shopping, two jerry cans and a wet dog. For two people a 2.4–2.6 m (8–8.5 ft) tender is enough; for a family of four you want 2.8–3.1 m (9–10 ft), and above that you are into catamaran territory where the extra weight is carried on a flat, wide transom.

Every dinghy carries a capacity plate stating the maximum persons, load and engine power. In the United States the plate is a USCG requirement for boats under 6 m (20 ft), and in the EU the builder's plate under the Recreational Craft Directive does the same job. It is not advice. Exceeding the horsepower voids the insurance and, more to the point, a tender that is over-powered rides bow-up, sees nothing ahead and flips when the driver falls off the throttle in a chop.

Two sizing checks nobody puts in a brochure. First, the dinghy must fit where it will live: measure the davits or the deck space before you look at a single tender, remembering that a dinghy on davits sticks out past the transom and adds to your marina length. Second, the tubes should be at least 40–45 cm (16–18 in) in diameter, because tube size — not length — is what keeps you dry at speed and gives freeboard with four people aboard.

The Outboard: Displacement or Planing

An outboard does one of two things. At 2.5–3.5 hp it pushes the dinghy along at hull speed, 4–5 knots, however hard you twist the throttle. Somewhere around 6–8 hp, with a light load, the hull climbs onto its own bow wave and planes at 12–18 knots, and the trip to the far cove drops from forty minutes to twelve. Between those two regimes there is a wet, noisy, expensive nothing, so pick one side or the other and buy the engine for it.

Then weigh it — literally. A 2.5 hp four-stroke is about 13–14 kg (29–31 lb) and one person swings it onto the rail bracket. A 3.5 hp is 18 kg; a 5–6 hp 25–27 kg; and from 8 hp upwards you are lifting 35–50 kg (77–110 lb) of engine over a lifeline from a moving dinghy. That job needs a hoist on the pulpit or a halyard led to a winch, and a bracket on the transom rated for it. If you are cruising as a couple and one of you cannot lift the engine, buy the smaller one. The three hundred landings do not need to plane.

Electric outboards

Electric outboards have become a serious option for the daily run. A 1 kW motor is roughly equivalent to a 3 hp petrol engine in thrust, weighs 10–15 kg including a battery that lifts off separately, starts every time, and can be charged from the yacht's solar. The limits are range and speed: a typical integrated battery gives 30–60 minutes at full power, or several hours at trolling speed, and no small electric motor will plane a loaded dinghy. For a couple making short trips in a sheltered anchorage they are close to ideal. For the distant cove, or a long fetch in wind, you still want petrol.

Where the Dinghy Lives: Davits, Deck or Tow

Davits are the cruiser's answer on boats from about 10 m up. The dinghy lifts out of the water in a minute, drains, stays clean and is far harder to steal. The costs are a transom that must take the load — a 3 m RIB with a 10 hp engine and fuel is around 100 kg hanging off the stern — and the motion offshore, where a dinghy on davits in a following sea is a liability. Most long-distance sailors strip the engine and lash the dinghy hard, or bring it on deck, before a passage.

On deck, upside down forward of the mast or on the coachroof, is the safest place for any tender in a seaway. It is slow to launch, blocks the view forward on a small boat, and needs a halyard and two people. It is also the only realistic home for a hard dinghy on a boat without davits. Roll-ups and air floors go in a locker, which is the entire argument for them.

Towing works for a short hop across a bay in daylight and flat water. Beyond that it does not. A towed dinghy surfs down waves into your transom, fills in a squall, flips at speed and, above all, comes off. The painter is the most-lost line in cruising: it chafes through on the stern rail, its knot works loose, or it wraps the propeller when you slow down. If you must tow, use a floating line long enough to put the dinghy on the second wave astern, take the engine off, tie a second line as a backup, and never do it at night or offshore. Pull it in before you enter a marina, before you anchor, and before the sun goes down.

Theft: the Most Valuable Unlocked Thing in the Bay

A 3 m RIB and a 10 hp outboard together are worth more than most of what is left on deck, and they float, untethered, twenty metres from a sleeping crew. Dinghy theft is the most common crime cruisers report in the Caribbean and parts of the Mediterranean, and the dinghies that go are overwhelmingly the ones left in the water overnight or tied at a public dock with a plain painter.

• Lock the outboard to the transom with a purpose-made clamp lock over the mounting screws. Do it every time, not just in known trouble spots.
• Carry a 3–5 m plastic-coated steel cable and a decent padlock, and run it through the dinghy's lifting eye and the engine's bracket to the dock every time you go ashore.
• Mark it. Paint the boat's name on the tubes in large letters and engrave it on the engine. A named dinghy is much harder to sell and far easier to find.
• Lift it at night. The oldest rule, and the one that works.

The Dinghy at Anchor

Every night at anchor the dinghy comes up. On davits that is a minute. Without davits it is a halyard from the boom end to the lifting eye, hauled until the tubes clear the water and the hull is lashed against the topsides. At minimum, if it stays afloat, the outboard is raised, the painter shortened to stop it reaching the rudder, and the drain plug checked.

The reasons are practical rather than nervous. A boat at anchor swings through 180 degrees several times a night and a long painter finds the propeller or the rudder every time; a squall at 3 am fills a dinghy faster than you can get on deck; and the dinghy that leaves you overnight leaves silently, like a dragging anchor. In the morning both look the same — a boat that is not where you left it, and no idea when it went. So the overnight routine is one sequence: dinghy up, engine locked, anchor light on, and the anchor alarm set on the phone with the radius drawn around the anchor, not the boat. The dinghy is the thing you can lock. The anchor is the thing you can only watch, and the alarm watches it while you sleep.

The Bottom Line

Buy the tender for the trips you make every day, not the one you make once a year. It will do three hundred landings a season and one beach picnic, and the boat that suits the landings — a 2.6–3.1 m aluminium RIB in Hypalon with an engine you can lift, or an air floor and a 3.5 hp if you have nowhere to put a RIB — is the one you will still be happy with in year five. Respect the capacity plate, never tow at night, lock the engine, and lift the whole thing at dusk before you set the alarm on the anchor.