A cheap sailing cruiser with an old and unreliable inboard, or no engine at all can be given a new lease of life relatively cheaply by simply bolting on a new outboard auxiliary engine. The boat can be re-engined at a fraction of the cost of an inboard installation, with the added benefit that if you use a lifting transom bracket, the outboard can be removed completely from the water while sailing, cutting down on hull drag, so maximising your speed and upwind ability.
Sail power engines
In the past 10 years 'sail mate', 'sail power', or similarly marketed outboards have gained in popularity, with just this demand in mind. Usually long shaft motors, they will have a number of features to suit the sailing cruiser, such as a battery charging circuit and high thrust, low pitch propeller and the gearing to match, for displacement craft. A quick word on battery charging circuits of such motors. They won't generally have a dynamo or alternator, so will just be the rectified AC current from the ignition system, at best trickling out about 6 Amps at 12 Volts. This is enough to run your compass light and depth sounder, and that's about it, so don't think you'll be running your fridge freezer and disco lights off it!
If in doubt… go deep
The shaft length of an outboard is usually measured from the inner top surface of the transom clamp to the cavitation plate (the horizontal plate over the prop). Outboards generally come in three shaft lengths; 15, 20 and 25 inches. Sometimes you can spot a spacer piece fitted into the leg of long shaft motor, although often nowadays a manufacturer will have different leg castings for the different length shafts.
The downside stated by the manufacturers of fitting a longer than necessary shaft motor is that it unnecessarily deepens the draft of the boat. For sailing cruisers which will have keels and rudders far deeper than any motor, this is not an issue. The consequences of having too short a shaft on a sailing cruiser motor are far more serious though. The very time the safety of you or your boat will depend on your engine will be when you are trying to claw your way off a lee shore into strong wind and steep waves. Often a shorter shaft motor that has always performed admirably will meet its downfall in such conditions, when the combination of steep waves and the short shaft will cause the prop to be lifted clear of the water, losing the boat valuable ground upwind while racing wildly and noisily, just to add to the stress of the situation. Even worse, a short shaft may need to be lowered so far down to be effective, its powerhead could be pooped by a following sea.
Do ensure though, if using a long shaft motor with a lifting transom bracket, that the bracket is man enough for the job. A long shaft motor develops greater torque effects at the bracket than its short shaft equivalent.
Two versus four
Another choice you will need to make is whether you go for a two or four stroke motor. Put very simply, two strokes are the kind of simple, nasal sounding engines, in which the lubricating oil for the engine's moving parts is added to the fuel, and then burnt with the fuel, creating that noxious smell reminiscent of teenagers' motor scooters. Four strokes are the sort of engines you find in petrol cars, with the lubricating oil being added separately to a sump and pumped continuously round the moving parts as the engine runs. A two stroke engine is lighter, more powerful for a given weight, cheaper and easier to service and mend than its four stroke equivalent, because it uses a simpler combustion cycle that does away with camshafts, timing belts, oil sumps and the like. A two stroke can also be thrown in the car boot without worrying about its oil draining into its cylinders. On the downside, although emissions laws have forced two strokes to clean up their act in recent years, they are still environmentally much more damaging than fours. In many inland waterways in the UK and Europe, there is no choice; two stroke engines are banned.
The argument for four strokes, providing you can live with the extra cost, weight and bulk is far more persuasive, for the cruising yachtsman, and not just for environmental reasons. Because they have a better lubrication system, they last longer, providing they are serviced correctly. Four strokes will also idle all day, which is great for manoeuvring in marinas, where two strokes will often begin to foul their plugs, run roughly and may eventually cough to a halt if idled for a long time. Even more importantly, four stroke engines are more fuel efficient, partly because there's no two stroke oil to buy. According to Mariner, their 4 stroke motors are typically 39% more economical than their 2 stroke equivalent. Finally, I'm yet to meet anybody who likes the messing about with measuring jugs and mental arithmetic that the mixing up of two stroke fuel entails.
What's in a name?
Look carefully at a number of different manufacturers' engines and you might start getting feelings of déjà vu as you spot familiar castings and features. That's because there's a lot of 'badge engineering' in the world of outboards, particularly the small ones. Mariner and Mercury are the same engines with different stickers on, as are Johnson and Evinrude. Mariner's Sailmate 4 is a detuned and re-badged version of Tohatsu's Sail Drive 5.
As Fairweather Marine's Head Technician Mark Compton explained, manufacturers should not be berated for such badge engineering,
“it's good news for the customer, as the sharing of tooling and design costs brings prices down. All these well known manufacturers' products are as reliable as each other, and all have 2 year warranties, so the most important consideration when buying an engine nowadays is the proximity of the dealer for your servicing and parts.”
The only traditionally independent manufacturers are Honda and Yamaha, although even these are now making some of their parts available to other manufacturers.
What about secondhand?
Although this article is primarily concerned with new engines, here, very briefly are some pointers for buying a second hand engine.
Always hear it run, unless it is being sold for parts at an appropriately low price. If the seller wishes to run it with no water 'just for a short time, won't do it any harm' etc., run a mile. You really need to run the engine up to operating temperature, which will take 5 minutes or so, and running it for more than a couple of seconds without water running through it could damage the water pump impeller. Hopefully it will be ice cold when you come to start it, if the motor has been pre-warmed… be-warned.
It should start within 2 or 3 pulls. Once it is running off choke, in neutral, in a bucket of water or with mufflers pumping water into it, make sure water is squirting out of the telltale under the cowl. Turn the throttle right down to idle and leave it there for a few minutes, especially if it's a 2 stroke; you want to make sure that lack of maintenance and a blocked idle jet aren't giving it trouble at low revs. Your world should not fill with smoke at this point, especially if it's a four stroke. A certain amount of blueish smoke should be expected with a two stroke.
Feel the temperature of the water coming out of the telltale, it should be warm, but not too hot to touch. If it's red hot and steaming, chances are that some of the waterways are blocked, the engine has been overheating, and you should walk away.
Have a visual check for oil leaks from the engine and corrosion on the leg. If you are outdoors, very briefly put the engine into forward and reverse gears, ensuring the prop turns. If it's in a bucket, prepare to get wet feet. If this can't be done, when the motor is stopped, put it in forward and reverse and with the cowl removed turn the flywheel slowly by hand, watching that the prop turns too.
When you hit the stop button the engine should stop quickly and smoothly. If it runs on, coughing and backfiring for 5 seconds with your finger on the stop button, it's probably running hot, badly coked and hasn't been well maintained.
Like any second hand good, the main consideration is the bona fides of the seller. Ensure there's a plausible story for the sale, that the motor has been serviced throughout its life and beware of stolen motors, they are a very portable item. The insurers' database of stolen outboards can be searched at www.stolenboats.org.uk.
