Why we build in aluminium (and what fibreglass still does better)
Lighter, no osmosis, repairable with a plate and a welder, and worth more after ten years. Five differences that only show up once the boat is old — and the cases where fibreglass is still the right answer.
Two questions come up in almost every first conversation: is aluminium strong enough, and will it corrode. Both have better answers than yes or no, and neither is the reason most of our customers end up buying aluminium. The reasons show up five years later.
1. It burns less fuel for the same speed
Aluminium is lighter than fibreglass for the same strength. On a like-for-like hull that is worth roughly 20 percent in fuel at the same cruising speed — or the same fuel for more speed. On a 12-metre boat doing 200 hours a year, that is a serious number over a decade, and it also means a smaller engine can do the job.
2. It does not absorb water
Fibreglass hulls are built around resin, and resin absorbs water slowly. That is osmosis: blisters under the gelcoat, a hull that gains weight, and a repair bill that arrives in year eight. Aluminium does not absorb anything. It also does not care about sunlight, which is why a ten-year-old aluminium boat usually looks newer than a ten-year-old fibreglass one kept in the same marina.
3. Damage is a plate, not a mould
Hit a rock in a fibreglass hull and you get cracking that spreads under the surface; the repair is a workshop, a mould and weeks. Hit the same rock in aluminium and the plate deforms. A dent can be pushed out, and a torn section can be cut out and welded in a day. The hull is back to full strength, not to 80 percent of it.
This is also why trailer transport is kinder to aluminium. Straps and rollers crack fibreglass over time; aluminium simply takes the load.
4. It does not burn
Aluminium is not combustible, and it does not feed a fire. A fibreglass boat that catches fire above the waterline can burn down to the waterline. That is not a theoretical difference if you carry fuel, batteries and people.
5. It holds its value
Because none of the above degrades, a used aluminium boat is worth more relative to what it cost. Depreciation is lower precisely because there is less to go wrong.
A boat is a promise that it will still be working in fifteen years. Aluminium is the material that keeps that promise.
Where fibreglass still wins
If you want a complex, curved, one-piece shape with a glossy finish, fibreglass is cheaper to produce. If your boat is under 5 m and lives on a trailer, a moulded hull is lighter and quieter. And if you are building hundreds of identical boats a year, a mould pays for itself.
Everything we build — from a 5.5 m skiff to a 15 m crew boat — is a case where those trade-offs do not apply. See the fishing range or the utility range for what that looks like in practice.
