Repairing a leaking hull-to-deck joint

If you suspect a hull-to-deck joint has failed, then being absolutely sure where the actual leak is occurring is of prime importance. Areas to check are near the deck fittings, where the decks may be put under considerable stress by the rigging and the continued flexing of the hull. Another area to check is where mooring cleats have been subjected to excessive strain or when a boat has been left tied alongside with insufficient fenders in place.

Hull-to-deck joints are designed not to come apart, so they are permanently bonded, often covered up and some are even glassed in. This can make repairing them very challenging:

Getting access – hull-to-deck joints are usually fastened with bolts from above and nuts below. Others are fastened by screws and others by rivets. Getting access to the underside of the fastenings usually entails stripping away the headlinings or panels. So the first thing to do is check what type of fastenings you have on your boat and then work out how you are going to get access to them and remove them.
Loosen the rigging – before you begin to unfasten things, it is a good idea to slacken off the rigging to ease the tension acting along the length of the joint.
Removing the rail – back on the outside, it is common for the joint to be protected by a rubber fender or toerail, which may be constructed either from aluminium or wood. The rail invariably needs to be removed first. Metal rails might be bolted, screwed or riveted. Wooden rails will be bolted or screwed.
With the rail removed – closely examine the joint and get a better idea of where the problem lies. It might be that there are only a few places where leaks are occurring, meaning that a localised repair is all that is required. A thorough inspection at this stage will help you decide.

Unfasten the joint – remove the fasteners holding the joint in place around where the problem lies. The reason for this is that you need to open up the joint in order to apply new sealant for the repair. Alternatively you may choose to re-bond the entire length.
Remove the old bedding compound – before new sealant can be added, all the old bedding compound must be removed, using a reefing iron or similar to scrape out the old material. Use wedges to separate out the joint flanges enough to get access for the repair.
Fill the joint with new sealant – with the old joint cleaned out as well as possible, fill the joint with polyurethane sealant, ensuring there is sufficient to reach well into the joint beyond the fastening holes. Once the sealant has been applied then remove any wedges and where possible clamp the joint to ensure there will be a good seal along its length.
Re-fasten the flange – re-fasten the flange with through-bolt fittings if possible , but if not use self-tapping stainless steel screws. Apply extra sealant beneath the heads of the bolts or screws, but leave the nuts beneath clear of sealant to make it easier for the joint to be undone in the future. Clean up any excess sealant before it cures.
Re-fasten the rail – re-fasten the rail, bedding it with polyurethane sealant and bolts or screws. Re-attach the fender strip if there is one.

Estimating your position at sea

Navigators use a combination of techniques to estimate their position at sea. The primary method used today is GPS (Global Positioning System), a network of 24 satellites that became fully operational in the 1990s and was originally restricted for use by the United States military.

How to predict wind direction and strength by reading a weather chart

Weather charts, also known as surface pressure or synoptic charts, contain a lot of information that helps weather...

Jester Challenge 2022 – Sailing single handed from Plymouth UK to the Azores: Part 9 – Around the Azores

Jester Challenge – A modern experiment in old-fashioned self-reliance, self sufficiency, and personal responsibility. This is the ninth of a 10-part post where solo sailor, Bernie Branfield, shares his first-hand account of his single-handed, 2022 Jester Challenge, from Plymouth, UK to the Azores, in his 26′ Invicta Mk2, Louisa.

Wooden Hulls – Part 1

Traditional wooden boats have a plank on frame construction, a centuries old boat building method that is still in use today. Variations of the traditional method include carvel, clinker and strip planking, which all relate to the way the planking is attached to the frame.

Boat engine cooling systems

Some boat engine breakdowns are unavoidable but those caused by lack of maintenance or regular checks can be avoided. Failure to maintain an engine’s cooling system is a well known example of this, so it is well worth spending time checking over the cooling system both when the boat is ashore and afloat.

Tools and spares for your boat

Tools and Spares to take to sea!

You won’t regret taking a look at our essential tips and checklist to make sure you’re prepared for routine maintenance and those unexpected jobs that come up whilst you’re afloat!

The VHF DSC Radio jargon buster

AIS - Automatic Identification System This system is used by shipping. It allows another vessel or coast station to use...

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.

Antifouling for leisure boats – Part 1

Boats that are kept afloat can very quickly become a home for small marine organisms such as barnacles, weed and slime. Applying an antifouling paint to your hull is necessary to protect it from these micro-organisms, as a fouled hull can cause problems and will slow down a boat’s maximum speed considerably if left unchecked.

Dag Pike’s Boat Survey

We're really pleased to be working with Dag Pike on some great new apps for iPhone & Android. Here'a a bit more about the first app: Dag Pike's...

Finding your way at sea: waypoints

Any sea voyage needs a certain amount of planning before it is undertaken. It makes sense to think about where you are going, how you will get there and what factors might influence your plan. Planning the route itself is also critical. One of the essential parts of modern navigation is the use of waypoints.

Jester Challenge 2022 – Sailing single handed from Plymouth UK to the Azores: Part 3 – Preparations

Jester Challenge – A modern experiment in old-fashioned self-reliance, self sufficiency, and personal responsibility. This is the third of a 10-part post where solo sailor, Bernie Branfield, shares his first hand account of his single-handed, 2022 Jester Challenge, from Plymouth, UK to the Azores, in his 26′ Invicta Mk2, Louisa.

You Need To Understand The IRPCS ColRegs To Pass Your Yachtmaster, Master of Yachts and Coxswain Certificate of Competence

IRPCS ColRegs Rules of the Road at Sea and Yachtmaster Learning, understanding and remembering the International Regulations...

Jester Challenge 2022 – Sailing single handed from Plymouth UK to the Azores: Part 8 – Arriving at the Azores

Jester Challenge – A modern experiment in old-fashioned self-reliance, self sufficiency, and personal responsibility. This is the eighth of a 10-part post where solo sailor, Bernie Branfield, shares his first-hand account of his single-handed, 2022 Jester Challenge, from Plymouth, UK to the Azores, in his 26′ Invicta Mk2, Louisa.

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.

Sailing into a storm

Weather forecasting has become increasingly accurate, but despite this, I was caught out recently by a forecast that considerably underestimated the wind strengths and consequently was sailing single handed in to a Force 8 gale, which proved to be challenging!

2023 Rolex Fastnet Race

Safe Skipper’s Simon Jollands took part in the 2023 Rolex Fastnet Race – a classic offshore sailing event. This is the first of several articles on the race and focuses on the start.

Jester Challenge 2022 – Sailing single handed from Plymouth UK to the Azores: Part 5 – Boat Management

Jester Challenge – A modern experiment in old-fashioned self-reliance, self sufficiency, and personal responsibility. This is the fifth of a 10-part post where solo sailor, Bernie Branfield, shares his first hand account of his single-handed, 2022 Jester Challenge, from Plymouth, UK to the Azores, in his 26′ Invicta Mk2, Louisa.