Select Page

The two metals used for hull construction are steel and aluminium. These are both very strong materials and will last a long time as long as they are cared for, which primarily means protecting steel boats from rust and aluminium boats from electrolytic action.

Metal boats have a long history dating back 200 years and of course most modern ships are made from steel. It is only in comparatively recent times that steel and aluminium have been used in leisure boat construction. Steel and aluminium are both strong materials and are popular with blue water cruising boats designed for living aboard. Each material has its advantages, but as a rule of thumb aluminium will be favoured by racing skippers as it is much lighter. Steel on the other hand may be heavier but it is a cheaper material, so for those not so concerned about top speed performance, this may be their choice.

Both steel and aluminium boats can be built by competent amateurs. This means that someone with good welding skills can save a lot of cost by buying a boat in kit form and constructing it themselves.

Steel hull construction

Steel hulls are constructed of a frame with steel plates welded to it. As soon as steel is exposed to the air it begins to rust, where the steel reacts with oxygen to form iron oxide. If seawater is added into the mix then the process accelerates rapidly. Steel boats built before the introduction of epoxy coating systems in the 1980s are more prone to rust and their hulls need to be closely monitored and re-painted frequently. Those with epoxy paint systems tend to be far more resilient, as long as the paintwork is not damaged. If it is, rust will very soon begin to appear.

Aluminium hull construction

Aluminium hulls are constructed in a similar way to steel hulls, but the two metals are quite different from each other. If you leave aluminium exposed to the air it will not rust, which gives it a big advantage over steel. However, aluminium suffers from electrolysis, which is the form of corrosion caused by different metals coming into contact with each other. The tell-tale sign, the equivalent to rust with steel, is a white powder which literally crumbles the aluminium away as you touch it. The two main preventative measures taken by builders of aluminium boats are firstly to ensure that different metals, such as aluminium and stainless steel, are very well insulated from each other and secondly through the use of sacrificial anodes.

If you are interested in purchasing a metal hulled boat or are already an owner of one, then the metal hull inspection checklist below will hopefully be of use to you.

Metal hull inspection

  • Check for any distortion in the hull that might have been caused by an impact or collision.
  • Check the outside of steel hulls for any signs of rust. If the rust is only on the surface it can be rubbed down and treated. If the surface is pitted it indicates a deeper level of corrosion and this will need to be taken back to the bare steel and treated.
  • Check for corrosion around the stern gear and through hull fittings, which could be caused by electrolytic action. Pay particular attention to where the heads through hulls are located as this is a known problem area.
  • Check that the paintwork is in good condition and the surfaces are all sound. Look for any signs of the paint bubbling which could indicate rust is about to break through.
  • Check all the anodes and replace if necessary.
  • Check the inside of the hull for any signs of corrosion, which will most likely entail reaching into inaccessible places using lights, mirrors and cameras. For a thorough hull inspection it helps to know where specific areas of vulnerability are. These include beneath fresh water, black water and fuel tanks. This is not necessarily due to the tanks leaking, but because of the condensation build up in these areas that can lead to pools of water forming. Another obvious place to inspect is the hull areas beneath where the shower or heads and galley are located. Seepage of water can work its way to these inaccessible areas, collecting along the frames with nowhere to go.
  • Look inside all the bilge areas and make sure they are dry. If water is allowed to sit in the bilges of a steel boat it will soon cause problems.
  • Check along the welding that joins the frame to the plating, as this is a common place for rust to start inside the hull.
  • Look carefully at the edges of any timber that is fastened to the steel. Check for signs of rust, as timber is notorious for taking up moisture which works its way between the timber and the steel, which then rusts.

Engine failure at sea – common causes and how to avoid them

Many engine failures are caused by lack of maintenance, resulting in fuel filter blockages, water pump failures, overheating and other breakdowns. Indeed, one of the most common reasons for marine rescue service call outs is for one of the most basic reasons possible – boats that have run out of fuel.

Jester Challenge 2022 – Sailing single handed from Plymouth UK to the Azores: Part 4 – Navigation

Jester Challenge – A modern experiment in old-fashioned self-reliance, self sufficiency, and personal responsibility. This is the fourth 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.

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...

First Aid Afloat – jellyfish stings

  Wherever you are boating in the world I am sure you will be using a pilot guide to aid your navigation. Often in the...

Jester Challenge 2022 – Sailing single handed from Plymouth UK to the Azores: Part 6 – Communications

Jester Challenge – A modern experiment in old-fashioned self-reliance, self sufficiency, and personal responsibility. This is the sixth 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.

Avoiding collisions at sea – how to stay safe on the water

Boats have many blind spots, including the headsails of sailing boats. Always keep a lookout, stay safe and remember that...

Antifouling for leisure boats – Part 3

Antifouling is one of the least pleasant boat maintenance jobs to do, but it has to be done. The very worst job of all is removing the old antifouling as this can get seriously messy and is very hard work.

The dangers of running aground in a motor boat

The peril of grounding a motor boat is not only an inconvenience; it can lead to substantial risks for both the vessel and its passengers. . In this article, we’ll explore the potential dangers of running aground and highlight the importance of proper navigation and preparedness to avoid these hazards!

Wooden Hulls – Part 2

It is important to ensure the essential hull maintenance of a wooden boat is done, even if you are paying others to look after your boat for you. The priority is to prevent rot from taking hold. The protective layers of paint and varnish over wood are far more critical than on GRP boats, where the topsides are painted more for cosmetic reasons.

Boat maintenance – what does it involve?

The maintenance of a boat involves things like cleaning, varnishing, painting, polishing, antifouling, servicing the engine, servicing the seacocks, and maintaining the gas and plumbing systems. It all amounts to a fairly considerable amount of work that can’t be ignored if you are to keep your boat in a safe and good condition.

Cutless bearing replacement

Cutless bearings can last for many years but if the propeller shaft is out of alignment they will wear through more quickly. If you have noticed a clunking sound when motoring then it could be a worn cutless bearing that is causing the problem.

Always have an emergency grab bag to hand when at sea…

  Grab bag: In the event of having to abandon ship, it is recommended to have a designated waterproof bag to carry...

Fractures, sprains and dislocations at sea

Moving about a boat at sea often results in a few knocks and bruises, but if a crew member has a fall or major bump and is in serious pain, they should be examined and treated accordingly.

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.

Boating Etiquette: Do’s and Don’ts on the Water

Boating etiquette is essential for ensuring the safety, enjoyment, and harmony of everyone on the water. Whether you’re a seasoned boater or new to the boating community, it’s important to be aware of the do’s and don’ts of boating etiquette. Take a look at our guidelines:

Essential Yachting + Power Boat Safety Briefing

Yachting Safety Briefing   Down below Lifejackets and harnesses - fitting, when to wear, clipping on Gas - risks,...

Top 5 Reasons Why an Inflatable SUP Should Be Your Next Yacht Accessory

In this article, inflatable paddle board expert Jason Paul gives the top 5 reasons why an inflatable SUP should be your next...

Sailboat rig checks – Part 2

In part two of Sail boat rig checks we run through some useful rig maintenance tips and then finish with a brief look at what a professional rig check involves.

Top Ten Tips For Learning The ColRegs Boating Rules Of The Road

Colregs Boating Rules Of The Road Skippers struggle to learn and remember the ColRegs Yachtmaster and Day Skipper course...

Boat Security: Protecting your vessel from theft & vandalism

Boats are susceptible to theft and vandalism. Protecting your vessel from these risks requires a proactive approach to boat security. In this comprehensive guide, we’ll explore the various threats to boat security and provide practical strategies and technologies to safeguard your investment and enjoy peace of mind on the water.

Nautical paper charts – a reminder of the basics

The nautical chart is an indispensable tool for navigation. A chart is a graphic representation of an area of the sea which might also include coastlines, estuaries and islands. All cruising leisure boats should carry up-to-date paper charts.

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!

Sailing Safely at Night – Best Practice

Sailing at night can be a magical experience – the peaceful solitude, starry skies, and gentle lapping of waves create an unforgettable atmosphere. However, nighttime sailing also presents unique challenges and risks that require careful preparation and vigilance. This comprehensive guide will cover essential safety practices to ensure your nocturnal nautical adventures are both enjoyable and secure.

DIY boat upgrades: Budget-friendly projects to enhance your (older!) boat

DIY projects that can enhance both the functionality and aesthetics of your boat. In this article, we’ll explore a variety of DIY boat upgrades that won’t break the bank but will significantly enhance your boating experience.

Diesel engine winterisation

An inactive boat engine needs to be protected from corrosion during the winter, caused by the rising humidity levels through the cold months and the salty coastal air. This applies whether the boat is left afloat or hauled out over the winter. Read here about the two important stages of winterisaton for a diesel boat engine.