Is an Aluminium or Fibreglass Hull the Best Boat for you?

7th February 2013

Picture of fibreglass and aluminium boat hullsThe issue of which is the best type of hull has been argued over for many years and I thought an article on the pros and cons of both constructions deserved to be written.

There will always be boaties who will swear by either fibreglass or aluminium and they will probably never be swayed no matter how many good arguments are put forward to the contrary but for the undecided or new boatie I give below what I consider to be an unbiased view of the merits of each type.

Strength – In a collision with a solid object (such as a wharf) a fibreglass boat will splinter with the damaged fibreglass falling into the deep whereas an aluminium hull will bend into a dent.

Weight – Aluminium is lighter than fibreglass which means a smaller HP engine will give the same performance.  This translates to a cost saving on both the motor and fuel costs.

Advantages and Disadvantages of Fibreglass and Aluminium Hulls

Handling – Lighter boats can feel less stable when manoeuvring at higher speeds.

Price – In general fibreglass boats are more expensive.

Ride and Comfort – In rougher seas a light hull can be more noisy and give a more uncomfortable ride.

Damage – Although small dents in aluminium hulls can be easily repaired larger damaged areas can be costly and difficult.  Minor damage on fibreglass hulls can often be fixed with a tube of Epifill for $15 or for larger repairs a professional repairer is not hard to find.

Temperature – As aluminium diffuses heat away quicker than fibreglass these boats can feel colder and condensation is more likely.

Anti-fouling – To help prevent marine growth when the boat is permanently moored anti-fouling needs to be applied and this is more difficult and expensive on aluminium (if your boat is trailered this point is not relevant).

Corrosion/Osmosis – Aluminium hulls can develop corrosion in a saltwater situation and electrical connections and other metal connections to the aluminium can also react causing corrosion.  Fibreglass on the other hand has a problem called osmosis which is caused when inner fibres absorb water and results in them rotting.  Usually this only happens due to flaws from the factory or unattended damage to the gelcoat (the shiny outer hull coating) allowing the ingress of water to the inner fibres.  Osmosis needs to be treated promptly.

Upkeep – Fibreglass hulls usually require less checking and maintenace as there are no welds, rivets or corrosion problems

Style – A fibreglass boat can be shaped and moulded into aesthetically pleasing styles with sleek lines a ‘tinny’ owner can only dream about.

Flaws – Bubbles in a fibreglass hull can weaken it and can be disguised easily but are impossible to detect on inner layers.

Timber Rot – Timber is sometimes used for fibreglass reinforcing such as cross members and can cause expensive problems if water gets into them.  These days manufacturers have found different methods which no longer require timber.

Summing up, there will always be different schools of thought on which is best but it is still a matter of personal choice and thank goodness for that, it would be a dull old world if everyone liked the same things.  The fish can’t differentiate which boat they get hooked from and both types will give boaties pleasure.  Having grown up with fibreglass they are my personal preference but as I have said – each to their own.


The information in this article was sourced from Powerboat Training New Zealand
Coast Guard and RYA approved power boat training in Auckland
Contact: Andrew Flanagan
Phone: 09 8321647 Mobile: 027 3456690
Unit 4 23B Westhaven Drive, Auckland

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