Journal · Gear Review
Seven through-hulls, all replaced in 2026 with GRP TruDesign seacocks and new clamps — one of the least visible jobs on the boat, and one of the most important.
Seacocks and hoses are one of the most common causes of a genuinely serious problem at sea — a failed through-hull or a burst hose below the waterline can put a boat in real trouble faster than almost anything else that can go wrong, and it's one of the least glamorous systems aboard, easy to overlook right up until the moment it fails. Gran Blau carries seven seacocks in total, serving the engine, the generator, air conditioning, the watermaker, both heads, and the sink drains — and in 2026 every one of them was replaced.
What's Fitted
All seven through-hulls now run GRP (glass-reinforced plastic) TruDesign seacocks — a composite alternative to traditional bronze, chosen specifically because it doesn't corrode or suffer the galvanic and dezincification problems that can quietly weaken a metal seacock over years in salt water, especially aboard a boat with as much DC electrical equipment as Gran Blau carries.
Every hose run below the waterline was fitted with new clamps at the same time as the seacocks themselves — deliberately, rather than pairing brand-new fittings with whatever clamps happened to already be in place. A seacock is only as good as the hose and clamps attached to it.
Why It Matters
Nobody chooses a boat based on its seacocks, and that's exactly the problem — they're invisible right up until one fails, at which point they're the single biggest thing standing between a minor leak and a genuine emergency. Composite TruDesign fittings remove an entire failure mode that traditional bronze seacocks are exposed to: corrosion from dissimilar metals and stray electrical current, which is a real risk on any boat with significant DC systems aboard. Replacing all seven at once, with new clamps throughout, means there's no single old, unknown-condition fitting quietly left in the system as a weak point.
Installation Notes
The job was done with the boat hauled out at Port Mataró — where Gran Blau is lifted for anti-fouling and below-the-waterline work like this — the kind of job that genuinely needs the boat out of the water, with every through-hull accessible from both sides rather than working blind. The whole job was carried out in spring 2026 by the yard's own team.
Living With It
Performance so far has been great. It's taken a major worry away from us, which has let us actually enjoy the cruising rather than quietly wondering about seven ageing fittings below the waterline every time the boat's left unattended at anchor or in a marina.
More From the Refit
This is one of nine systems covered in the refit overview — see the rest, or sign up to the newsletter for each new review as it's published.
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