Updated October 26, 2026
How surveys describe it
Wording varies by surveyor. Illustrative examples (not quoted from any real survey):
- “Seacock for the engine intake is frozen in the open position.”
- “Through-hull fitting shows corrosion; recommend replacement.”
What it is
Through-hulls are the fittings that pass water in or out below the waterline. Seacocks are the valves on them. If a seacock is seized, you can't shut off water when a hose fails.
How serious it is
A failed below-waterline fitting can sink a boat, so seized or corroded seacocks are usually a fix-before-launch item. Replacement normally needs the boat out of the water.
In our reports this usually lands under Fix. Your survey's details decide.
What it typically costs
| Scope | Estimated range |
|---|---|
| 1 item | $290–$950 |
| 3 items | $850–$2,800 |
These ranges combine typical parts costs of $75–$250 per item with our assumption of 2–4 labor hours, priced at $110–$165 an hour, a typical Florida shop rate.[1][2][3]
- Boat is already hauled
- Bronze or reinforced-composite fitting with a new backing block
- Larger fittings cost more
Estimates to help you frame a conversation with a yard, not quotes. Real prices depend on the boat, the yard, access and what's found once work starts. Confirm with your surveyor or a qualified yard.
What to ask your surveyor or yard
- Which fittings are affected, and are they below the waterline?
- Can they be freed and serviced, or do they need replacing?
- Can this be done while the boat is hauled for survey?
Have your survey already?
Upload it and get every finding sorted into fix, negotiate, watch or ignore, with the surveyor's page and words beside each one.
Get a free previewSources
- Marine Mechanic Rates: What You'll Pay Locally, Marco Boatworks (Southwest Florida). Repair shop's price guide. Accessed 2026-10-26.
- Mobile Marine Mechanic vs Boat Yard: Real Tradeoffs, Boat Repair Miami FL. Repair shop's price guide. Accessed 2026-10-26.
- Through hull / seacock replacement, SailboatOwners.com forums (owner reports). Boat owners' reported prices. Accessed 2026-10-26.