When you want to know what goes wrong on yachts and powerboats on a regular basis, who better to ask than the marine equivalent of the AA recovery service?

‘Boats are becoming bigger and better than ever before,’ explained Nick Eales, the managing director of Sea Start. ‘But they’re also becoming far more complex, so the majority of our call outs are for electrical failures. This year we’ve also seen a huge increase in the diesel bug, which can stop even the biggest motorboats dead.’

Some breakdowns are unavoidable, and can happen to the best of us. ‘We’ve had at least eight boats disabled in the same area within three days – and all with fishing net around their props. It all looked the same type, too. Trawlers are venturing into much rougher ground to make their catches, which rips their nets to shreds.’

The good news is that if you call Sea Start, they claim to be able to fix 92% of their customers’ breakdowns. The company covers the most popular areas of the South Coast and is expanding, with more staff and agents in north Brittany and the Channel Islands. They attend an average of 1,600 breakdowns a year, and can provide anything from an on-the-spot repair, to a long tow back to the nearest safe haven.

On the mend

But, we asked, aren’t things improving on the breakdown front? Surely the RYA’s diesel engine course for leisure boaters is reducing Sea Start’s workload? In fact, Sea Start even offer the one-day course themselves at their Hampshire headquarters, and have plenty of teaching aids from real-life breakdowns.

‘Boat owners are certainly becoming more mechanically aware, and they’re learning to make the proper checks before they sail,’ Nick said. ‘We often troubleshoot over the phone, allowing owners to fix a fault themselves. But saltwater is hard on machinery, and sometimes a crew is just too tired, or too seasick, to fix a breakdown, even if they have the spares and know-how.  Some faults are simply too complex to repair at sea anyway.’

So what are the repeat offenders, and how can they be prevented?
Nick and his team of engineers religiously keep records from which they compile a set of figures at the end of each season. The split is about 50/50 between power and sail. In descending order, these are the most common breakdowns based on nearly 1,700 call-outs in 2004.

1. Engine electrics
23% of call outs

By far the biggest stopper (or non-starter) of all engines is an electrical system failure.
‘A real killer in fast sportsboats is water in the bilge,’ Nick suggests. ‘And it only takes an inch or two. When the bows lift, the water rushes aft and sloshes into the back of the engine, where the flywheel sprays it onto the starter motor. Owners must keep the bilge dry at all times, and that means sponging it out. It’s worth the effort, as replacing the starter motor is a major job.’
‘If you do have a starting problem, our advice is to check for the obvious first. On flybridge motorboats, for example, the fail-safes will lock out the controls at the lower helm position if the upper helm controls are even slightly engaged. That’s definitely a problem we can fix over the phone’.

2. Fuel systems
16% of call outs

A clogged up oil filter (left) and its new replacement

‘Running out of fuel is on the increase,’ Nick says. ‘We’ve found that boat fuel gauges are notoriously inaccurate, and are often reading a quarter full when the engine is sucking fumes. Owners expect them to be as accurate as the ones in their car, so trust them implicitly.
Running out of fuel at sea in a big motorboat can be a real pain, as it can take up to 180lt (40gal) simply to bleed the system and then get you home. Very few boats will carry enough spare fuel for this, so make sure you dip your tanks, and try and keep them over half full. Know the boat’s range. Many owners base their calculations on fair weather motoring, and wonder why they run out when bashing into a headwind.
‘Diesel bug that grows in the diesel/water interface in fuel tanks is more prevalent than ever. Many of the diesel bug treatments that kill it off are counter-productive, as the dead bugs sink to the bottom of the tank and clog the filters. Choose a treatment that turns the bug into a combustible product instead, so no sediment is left behind.
‘Another regular problem is owners filling their water tanks with diesel, or their diesel tanks with water – easily done by a tired crew after a long passage! ‘Although all Sea Start boats carry a raft
of spares, it’s a real bonus when the owners can provide the right filters for their particular engine, especially if it’s a rare one. ‘The primary filters are the ones that get blocked. Keep at least two sets per engine on board, plus a spare set of fine filters.’

3. Overheating
14% of call outs

A typical broken impeller – but where have the blades gone?

‘Rubbish in the water – especially plastic bags – cause a lot of blockages with intakes,’ Nick says. ‘Another regular customer is the failed water-pump impeller.
‘It’s important to remember that the broken blades of the impeller may well have been sucked into the cooling system, and need to be removed before a new one goes in.
‘We often get problems with the strainers on the saildrive engines, as well as on bigger engines such as the Volvo KAD series. The strainer is designed to be removed for checking and cleaning, but some owners fail to replace the seal properly. This causes the engine to lose suction and overheat.

Forceps are being used here to retrieve broken impeller blades

‘A good tip is to smear Vaseline on the rubber seal and check it carefully before reassembly. A further check is to run the engine at two thirds throttle with a squirt of detergent in the strainer. This should produce tell-tale bubbles at the exhaust end.’

4. Batteries and isolators
13% of all call outs
‘A failure in a battery isolator switch is simple to repair, but in the meantime will shut down the whole boat. RIBs and small sportsboats are very prone to this, as the switches are often partly exposed to spray.

‘The poles often support a lot of wiring, and the switch tends to fail internally. Unfortunately, a multimeter still records continuity across the terminals, so it seems fine, but it just can’t take any load. Battery isolator switches are simple and inexpensive, so if you have any suspicions, just swap it for a new one.

‘Batteries also top the list – usually due simply to a lack of fluid, or from cells dropping out. Faulty terminals, where clamps have been banged on with a hammer, also feature highly.’
Nick’s engineers carry emergency portable power packs to jump-start engines, especially as many incidents are on boats at anchor with no access to shore power. Keeping a power-pack aboard, or even a spare battery, will at least allow you to get home again’

5. Fouled propellers and drives
12% of all call outs

Another breakdown that’s on the increase is the fouled propeller – tangled in fishing net, pot markers or stray rope – which can be either an inconvenience, or a catastrophe.
‘Outdrives are the easiest to get to, as the drive leg can usually be lifted, and we can get at the prop from the RIB. Saildrives are the worst, because the propeller is deep under the hull and virtually inaccessible. Then all we can do is tow the boat in. Remember to check the drive carefully after you have cleared a foul, as the shaft may have been bent, or the propeller damaged – especially if it’s a duo-prop.’

6. Gearboxes, saildrives and steering gear
6% of all call outs

Cone clutch failure in saildrive or outdrive legs is usually caused by the clutch being ridden or slipped during manoeuvres, and it’s a boat-out-and-strip-down repair. The only prevention is by using positive action with the gear lever.
‘We’ve also had a number of saildrive propellers fall off,’ Nick says. ‘This is because they aren’t replaced properly when the ring anodes have been renewed at the start of the season. All types of steering – even tiller steering – have the potential to fail. We’ve had several problems with hydraulic steering rams failing, or the ends of cables giving way. Again, a close visual inspection for signs of corrosion, or hydraulic leaks, will detect any problems before they get too serious.
‘Rudders (or outdrives) can usually be centred and the boat brought most of the way home under a jury rudder.’

7. Major mechanical failure
5% of all call outs

Full mechanical breakdowns account for a relatively small proportion of call outs. Typical scenarios have been broken camshafts, dropped valves or cracked cylinder heads.
‘Yachtsmen often think that because they can sail, they’ll be fine if their engine folds. But a yacht with no wind is in just as much of a pickle as a powerboat with no power. Even if they have a stiff breeze, they can’t always sail right into a safe haven; especially if it’s directly upwind or extremely busy, so will still need a tow at some stage. When broken down yachts call us up, we usually ask if they can sail themselves into a sheltered anchorage where we can assess the damage in relatively calm conditions.’

8. Drive belts
4% of all call outs

Nearly all marine engines use external belts and some engines, such as the Volvo KAD series, can have up to four of them. ‘Belt slippage often goes undetected, but can give some real problems,’ Nick said. ‘The belts seem fine with a casual glance at tick-over, but start to slip when under load, especially when a lot of draw is on the alternator. Look for black belt dust on or around the engine pulleys, and test them for tension by pushing them in. Keep new spare belts aboard, and use them to gauge the thickness of the ones already on the engine.’

9. Ancillaries
4% of all call outs

A badly corroded hydraulic ram caused the oil to leak out through this fitting. The ram was relatively new, but the boat had been moored alongside a steel mooring post which set up some powerful electrolysis

Trim tabs, power trim and tilt, and gear and throttle cables have a habit of parting company when needed the most. This is especially true of gear cables, which are usually protected in a sealed unit. They aren’t a serviceable item, and the gear selectors on a binnacle are the worst offenders. The cable will often fail  when you need reverse, giving you acceleration ahead instead of slowing you up.

‘The gear cable s aren’t expensive, averaging around £20-£30 per unit, and I would suggest replacing exposed ones every five years or so to avoid an embarrassing shunt in a marina.
‘We also get a lot of outdrives jamming after being raised, often when small sportsboats have deliberately run up a beach. Volvo ones can be pushed back down by depressurising the hydraulic system, but Mercruiser drives are a bit more stubborn.’

Gear cables can fail within the sealed unit, but it’s often possible to disengage the drive by knocking the actuator up manually to the neutral position

10. Leaks – water and fuel
3% of all call outs

‘These are relatively rare, but can be alarming. A common cause is corrosion in exhaust water jackets, or people standing on the high-pressure fuel lines of an engine during maintenance jobs.
‘Hoses also perish, or clips become loose from engine vibration. A regular visual check of your engine, especially after it has been laid up for a while, will detect early problems.
‘Carry spare hoses and clips, and make sure new hoses are double clipped for extra security. Keep the coolant topped up with anti-freeze on engines with a closed cooling system, as it also contains important corrosion inhibitors.’

Nick’s top tips to avoid his assistance

Carry all the consumable spares for your engine, advises Nick Eales

• Attend a diesel engine course. You’ll learn how to spot potential problems, bleed a fuel system, and be taught to carry out preventative maintenance
• Keep a full set of consumable spares aboard, such as filters, belts, hoses and impellers. Have all the tools necessary to fit them. Sail into sheltered waters if you can before effecting a repair. It will make life much easier
• Don’t trust your fuel gauge – they are notoriously unreliable. Carry spare fuel, and regularly dip your tanks
• Tackle the diesel bug with a formulation that doesn’t just kill the bug, but eats it and turns it into fuel. Look at brands like Fortron, Marine 16 or Fuelset
• Sportsboaters should always run a dry bilge. Don’t just pump it, sponge it! Replacing a starter motor often means lifting the engine, so it pays to keep the water where it belongs – in the sea

Sea Start RIB Jesse James
What makes an ideal rescue boat? Nick has designed and built his own Land-Rover of the sea, a 9m RIB to complement his existing fleet of open RIBs. Because Jesse James has been coded Category 3 for waters up to 20 miles offshore, she has to have a cabin. She also has a pair of 230hp Yanmar diesels on Bravo 1 legs giving a top speed of around 46 knots.

‘The boat was literally built around the towing post,’ Nick explained. ‘It’s absolutely solid, and attached to the keel with 16 x M12 stainless bolts.’

A high bow and a relatively high freeboard make her a great sea boat, and the roof is important for keeping the sun off, rather than the rain.

‘We average 140 miles a day, and the engines need their 100-hour service every five weeks.’ Bearing in mind the average use of a pleasure boat engine is 50 hours a year, that’s a lot of use. Jesse James’ most effective remedy for an incurable breakdown is her towrope. It’s made from 16mm multi-plait nylon, and Nick swears by it. ‘It has a lot of stretch, and if you use the whole length, it really soaks up any snatching.’

Side tows are used in restricted waters but wash from other boats can be a real problem