How to Buy a Boat - 7 Hull Material Options

For those who are wondering how to buy a boat, there are a lot of choices, but basically sail or power. Once that basic decision is made, then there is the choice of boat hull construction, usually decided by the designer and not the boat builder. For those who are buying a used boat or home boat building, there are many choices. Most modern boats are made of GRP - glass reinforced polyester aka fibreglass. It offers many benefits, but there is a down-side too. Here, we look at 7 of the wide range of hull materials available, together with the main pros and cons of each type.

Composite GRP (Basic/Traditional)

This is the most common production material. Older vessels used very heavy 'layups' - thicknesses of woven and chopped strand glass mat. For: GRP has a good strength to weight ratio, low maintenance requirement, and is cheap for high volume construction. It is simple to repair - minor repairs are easily fixable by a competent home handyman. Against: Older compounds can present osmosis, and bleaching in prolonged sunlight. Modern resins are more resistant. Ideal for: All round uses - e.g. motor yachts, sailboats, dinghies and even minesweepers!

Composite (Exotic)

This boat hull construction use Kevlar or carbon fibre mat, with a high perfromance polyester or epoxy base resin.

For: Great strength/weight ratio. Against: Expensive to build, requires high-tech (= expensive) repair. Ideal for: Racing and high performance craft, big budgets.

Composite (Epoxy on foam or balsa core)

This is was popular build for one-offs, and also for volume production, though foam has now surpassed balsa.

For: Good strength/weight ratio, cheap and quick to build. Against: Difficult repairs. Major problem if the core is balsa wood and water gets in (a very careful survey needed here). Good for: Home build, one off designs.

Composite (wood strip, epoxy coated)

Usually built with cedar strip planks for stiffness, strength and shape. For: Moderate strength to weight, cheap and quick build. Against: Not easy to repair. Ideal for: One off and home build projects.

Wood / Timber (traditional build)

After the floating tree and dugout canoe, the oldest build was timber boat building, with some 'modern' variations. A range of planking types: clinker (overlapped), carvel ('smooth panked'), diagonal (single/double/triple layup). Double or triple diagonal may be laid up cold or oven cured - no longer produced these days.

For: Lovers of wood, tradition. Against: Generally lower strength to weight ratio. Increasingly difficult to find craftsmen for repairs, high maintenance requirement, fastenings corrode. Ideal for: owners with time and money.

Wood (plywood)

Plywood started the home-build market way back in the early 1950's. Some smaller designs use the 'stitch and glue' technique. There is also a 'lapstrake' variation.

For: Cheap and easy to build, light to moderate strength/weight ratio. Against: Moderate maintenance requirement. Poor quality non-marine plywood may have been used, and there are design constraints. Ideal for kits.

Steel

For: High strength:weight (for builds over 38'-40'), cheap and easy to build, cheap and low-tech repairs and modifications, very durable. Against: Corrosion/maintenance. Ideal for: All round use, one-off designs, home build, larger vessels, even kits.

Aluminium Alloy

For: High strength:weight, durable, low maintenance (no painting necessary above water). Against: Specialist builders, repairs and corrosion. Ideal for: Those who must have higher performance with a durable material.

RIBs

Rigid inflatable boats usually have GRP base hulls, with inflatable collars, and really fall outside the scope of this overview.

Whichever hull construction you opt for when you buy a used boat, do get a professional survey (unless of course it's a small dinghy or inflatable), or get it checked over by a knowledgeable friend. Many plywood, strip planked and steel boats may have been amateur built, with variable quality hidden faults. But be careful - there are many bad examples of commerically built GRP boats too, even modern ones.

This was just a bbrief summary of the constructions used for boats. If you are thinking of buying a used boat, or even building a boat, then there are other materials too, some of which can offer good value for money.


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The author has more than 50 years experience with boats,
from home build dinghies, wooden lifeboat conversions, major GRP repairs and a fair share of the problems that go with boats, plus the
fun! Discover a whole lot more other hull materials too and
over 15 engine checks you must make before buying.