Select Page

Leaking decks are perceived as a nuisance by some boat owners, who are often prepared to put up with them and turn a blind eye – “That’s boats for you!”. The reason for this might simply be explained because many boats are only used when the weather is fine.

If rain isn’t falling and water is not washing over the decks then a leaking deck can easily be forgotten about when the sun is shining, even if there are telltale signs of water ingress below in the cabin and bilges.

The problem here is that if the leaks are ignored a much more serious situation may well be developing, especially in the case of boats with balsa or plywood deck cores. Rot is likely to be occurring. Rot can’t be ignored on a boat, even on a fibreglass boat, as wood is used to strengthen the structure both of the hull and deck. So deck leaks do need to be investigated and dealt with.

Leaking decks

It can be quite a challenge to find the source of a leak. It helps if two people are involved in the search, with someone up on deck with a bucket of water or a hose and another down below looking out for the drips. Common sources of leaks include:

  • Deck glands – the fittings where wires and cables pass through the deck. These can fail because the rubber gaskets wear out, or sometimes the glands are not the right size for the wires passing through them. These can be fixed easily by replacing the rubber gaskets or by using a good quality silicone sealant such as Sikaflex 291i, which is ideal for bedding deck hardware.
  • Deck fittings – the average boat has a considerable number of deck fittings serving a variety of purposes. Each one of these could be the potential source of a leak. Removing them all and re-bedding them would be a major task, ideally done when the boat undergoes a major refit. It is best to start with the most likely culprits, those that are subject to heavy loads. These include mooring cleats, stanchion bases, genoa tracks, winch bases, toerails as well as pushpit and pulpit bases. The fact is that a lot of deck fittings are subjected to heavy loads and all have to endure a marine environment. 

Leaking decks

  • Windows – leaking windows are easy enough to detect but if in doubt the bucket of water test or hosing the window from outside will confirm if there is a problem. Window seals fail when the gasket or sealant hardens with age and no longer provides a flexible seal. The temptation is to try a quick fix by simply running some new sealant around the edge of the window – not the answer. Repairing a leaking window can be a time consuming job if it is done properly. The window needs to be removed completely in order to replace the seals. 
  • Chainplates – it is wise to do an annual check of the chainplates. Chain plates fail for the same reasons standing rigging fails – corrosion and metal fatigue. On many boats access to the bolts that secure the plates to the bulkheads or knees is difficult as they are buried out of sight behind bulkheads, or glassed in completely. If a bulkhead shows signs of damp, then a leaking chainplate could be the cause. A full inspection needs to be done, not only of the chainplate fixing itself but also checking for rot in the deck core and where the plate is attached. If you suspect this may be the case, then access is essential as the fitting will need to be cleaned up and re-sealed with a flexible non-setting sealant and possibly new bolts will be needed, depending on their condition. Stemhead chainplates which secure the forestay can also be difficult to access. Some are located in anchor lockers where they come into contact with salt water, which is not at all good. 

Leacking boat deck

  • Hull-to-deck joint – most GRP boats are constructed with separate hulls and decks. These can be joined together in a number of ways, with some having an inboard flange on the top edge of the hull onto which the deck is bolted; others having an outboard facing flange on the hull and deck; a third type have a joint where the deck fits over the hull – like the lid of a shoebox. All joint types are coated with sealant, bolted together and rubber or wooden strips are added to finish them off. These joints can fail after impact damage or when a boat has been subjected to the considerable stresses incurred when pounding through rough seas, causing the hull and deck to twist, distort and ultimately separate.

 Filling old screw holes

 When deck fittings are removed or upgraded the old screw holes need to be filled to ensure no water can find its way into the foam or wooden core beneath. The best way to do this is to clean the old hole up with acetone, or if necessary first enlarge it with a slightly bigger diameter drill bit and then clean and dry it. Next fill the hole with epoxy resin mixed with glass bubbles which results in a strong, lightweight filler that can be sanded and then painted.

Going aground – what to do if it happens to you

When a yacht runs aground, it can be a stressful situation, especially on a falling tide in an exposed position with a swell running. There are several steps you can take to address the situation in order to ensure the safety of your vessel and its occupants. Here are some tips should this happen to you.

How diesel engines work

The basic principle of a diesel engine is less complex than that of a petrol engine. No spark plug or ignition system is needed, making the basic diesel engine a comparatively straightforward system that results in fewer faults and has lower maintenance costs than a petrol engine.

Docking a Motorboat

Docking a motorboat can be a challenging task, especially for beginners, but with practice and attention to detail, it becomes much easier. Here’s a step-by-step guide to help you dock your motorboat safely and efficiently.

Boat interior inspection and checks

While a boat is ashore, the most critical interior checks to carry out are those that concern the safety of the boat. This entails the integrity of all through-hull fittings and seacocks, the gas system and the electrical system.

Essential Boat Safety Briefing

Skippers Responsibilities Skippers are obliged to give a safety briefing to the crew even if they are a regular crew. At...

Boatyard Health and Safety

Boat storage facilities are potentially hazardous environments and it is the responsibility of both boat owners and boatyards to ensure that the...

Boat interior varnishing

Most boat interiors have a combination of varnished and painted surfaces including solid wooden joinery, plywood laminates with thin hardwood veneers and glass reinforced plastic. When making your assessment of what you are going to do, bear in mind that the varnishing process consumes a lot of time, especially if the existing surfaces are in poor shape.

Boat engine basics

Boat engines come in all shapes and sizes and include inboards, outboards, petrol, diesel, electric and hybrid systems. Some engines are...

A simple guide to understanding tides when passage planning

Understanding tides when passage planning When planning a trip in tidal waters, check the tides before going afloat. Use...

Understanding marine sealants & adhesives

Sealants, adhesives and adhesive sealantsThere is a bewildering variety of sealants, adhesives and even adhesive sealants available for...

Boat decks and superstructure

The deck of a boat is constantly exposed to the elements and should be inspected on an annual basis. Particular attention needs to be given to the overall condition of deck fittings such as the stanchions, cleats and chainplates.

ColRegs when sailing single handed

  Don’t neglect the Colregs when sailing single handed Sailing single-handed represents several challenges for skippers, not least how to...

Tidal heights and the rule of twelfths

For those skippers who need to make a quick calculation or don’t have access to specific tidal curves for their location, it is possible to make an approximation using a system called the Rule of Twelfths. This is a simple method used to estimate the height of tide at any given time during the tidal cycle. It is based on the idea that the rise and fall of the tide is not constant, but follows a predictable pattern than can be divided into twelve parts.

Essential Knots: Reef knot

Essential Knots: Reef knot Use: Tying two ends of rope together, often used for tying up a bundle of loose sail around the boom. Step...

Common medical emergencies at sea

A medical emergency aboard a boat at sea requires immediate attention to ensure the safety of the casualty and the crew in general. The skipper needs to know which crew members, if any, have had medical training or have a first aid qualification. All boats should carry first aid handbooks to help an untrained crew cope with a medical emergency.

Marine engine electrical system

The typical basic electrical system associated with a marine engine includes a dedicated engine starting battery, a starter motor, a charger in the form of an alternator, a solenoid and some engine sensors and instruments.

Passage Planning Advice & Safety for skippers

Passage planning helps you to: • Decide where to go • Calculate how long it will take to get there • Avoid bad weather •...

Safety Briefings – leave nothing to chance

Before giving your crew a safety briefing, it is worth considering the specific circumstances of the planned trip, the...

Rig check – how to prevent failure at sea

Regular rig checks prevent the risk of mast and rigging failure at sea. This includes regular rig inspections of the spars, ...

Saildrive maintenance

There are less maintenance tasks to carry out on a saildrive transmission than on a traditional inboard shaft drive system with its associated stern gear. However, there are a few critical things that require maintenance, as recommended in detail by the engine manufacturers, and should be adhered to.

Cleaning & polishing painted topsides

The gelcoat topsides of a GRP boat can be pampered and restored to their former glory relatively easily when it is ashore. Gelcoat is only a very thin outer layer of the hull, often less than 1mm thick, so you should avoid cleaning it with highly abrasive cleaners, or an-ything that could potentially damage its surface.

Marine toilets – care and maintenance

There are a number of different types of marine toilet, or heads. They fall into one of three categories – manual, electric and vacuum, the most common being the manual, hand pumped type. These have double acting piston-pumps which both discharge the waste and flush the toilet with sea water.

Learning about diesel engine maintenance

Marine diesel engines are internal combustion engines that are designed specifically for use in maritime applications. These engines are commonly used in a variety of watercraft, ranging from small boats and yachts to large ships and vessels. Learn about marine diesel engine maintenance courses.

Keel maintenance and Repair – Part 2

If you have ever witnessed a boat colliding with a rock or other submerged obstacle you will know that there is an almighty thump and the whole boat shakes and judders. While such hard groundings seldom result in catastrophic keel failure, something has to give and even the sturdiest keels can easily be damaged by such an impact.

Sailing at the touch of a button

Easier and more controlled sail handling can also be achieved by powering up a furling mast. I came across some interesting solutions at the Southampton Boat Show this week on the Selden Mast stand, where they were running demos of their E40i electric winch and SMF furling system.