Skip to content
YachtSurveycom.tr

Hull Survey

The most expensive repairs come from below the waterline. Moisture, osmosis and the keel joint reported with measured values.

  • The hull is scanned on a grid and a moisture map is produced
  • Skipper 5 for fast scanning, Wetsoon Pro to confirm
  • Sounding hammer survey for delamination
  • Ultrasonic thickness readings on steel and aluminium
  • Osmosis graded by extent and depth
  • Skin fittings, anodes and bonding tabulated
Book a SurveyCall Now

A hull survey examines the underwater hull for moisture, osmosis, delamination, thickness loss and keel-joint condition, using measuring instruments. The boat must be ashore and dry. The work takes 4-6 hours.

Marine growth on the shaft, cutless bearing and propeller
Shaft play, cutless bearing wear and fouling thickness are measured by hand and recorded.

Why the underwater hull is the critical zone

The most expensive repairs a boat can present — osmosis treatment, laminate repair, keel joint rework — almost always come from below the waterline. And this is the one zone that cannot be seen at all while the vessel is afloat.

Tramex Skipper 5 moisture meter
The Skipper 5 does the fast sweep; every suspect point is then verified with a second instrument.

How it is examined

After haul-out and washing, the hull is scanned on a grid with the Skipper 5 moisture meter and suspect areas verified with the Wetsoon Pro; readings are mapped so the report shows whether moisture is widespread or local. Percussion testing hunts voids and delamination that leave no surface trace. On metal hulls, ultrasonic thickness measurement documents corrosion wastage and past plate repairs. Skin fittings and seacocks are operated, anodes and bonding checked, and shaft, propeller, cutless bearing and rudder stock measured for play. The keel joint and keel bolts receive particular attention.

Percussion hammer testing on the hull of a boat hauled ashore
Percussion testing catches a void inside the laminate by the change in sound — while the surface shows nothing at all.

Why measure, rather than look?

The three defects that matter in an underwater hull all advance without showing on the surface: moisture in the laminate, a debonded core and thinned plating. All three look sound to the eye, and all three are among the most expensive repairs a boat can carry.

That is why a hull survey is a scanning job. The surface is divided on a grid, a reading is taken in each cell, and the values are plotted into the report as a map. This shows whether moisture is widespread or confined to one area — the distinction that decides what the repair will cost.

Moisture meter readings taken on a grid across the hull
Moisture is scanned on a grid; the readings enter the report as a map, not as a single verdict.
Propeller, shaft and rudder blade inspected on the underwater hull
Propeller, shaft and rudder are assessed together: bearing play produces vibration, and vibration fatigues the stern gland.

The report

Moisture values with their locations; osmosis graded for extent and depth where present; every defect photographed and urgency-classed, with cost ranges for items needing repair.

Thermal camera scanning the topsides of a hull
A thermal camera separates a water-holding area by its temperature difference — a second reading that confirms the moisture meter.

Duration and fee

A hull survey takes 4-6 hours, and the osmosis test is part of that work — the two are not carried out separately and are not billed separately.

Scope Fee
Hull survey + osmosis test 10 € / ft
Within a pre-purchase survey No separate charge — full survey rate 26 €/ft

On a 40 ft boat, hull + osmosis comes to 400 €.

Fees vary with the length of the boat, where she lies and the season. For a firm price call us — tell us about the boat and we will give you the number on the phone.

Estimate your survey fee

From the field

What this work looks like on board

8 frames

These frames were taken during real surveys. None of them are stock: each one is a measurement or a check described on this page.

Frequently asked questions

Common questions

How long should the hull dry before moisture readings?

At least 24-48 hours after pressure washing. Readings taken on a freshly hauled, wet hull mistake surface water for laminate moisture and give misleadingly high values.

Is osmosis a reason to walk away?

Not by itself. What matters is its extent, depth and whether it has reached the laminate. Superficial blistering is a manageable maintenance item; widespread, deep osmosis is a serious cost. The report draws that line with measured values.

What does a crack at the keel joint mean?

The thin "smile" line between hull and keel can indicate fatigued keel bolts or a past grounding. It hides easily under antifoul, which is why the joint area is specifically cleaned and examined.

Services

Other services

Contact

Book your survey

Tell us where the vessel lies and your approximate date — we reply the same day.

Serkan Kotel — yacht surveyor, portrait

Serkan Kotel

Yacht surveyor · IIMS · ABYC · MCA — the person who answers the phone, walks the boat and signs the report is the same person.

Service areas

Bodrum · Yalıkavak · Turgutreis · Milas · Göcek · Fethiye · Marmaris · Datça · İstanbul · Ayvalık

Message on WhatsApp