Steel is the most robust material for large bluewater cruisers, expedition vessels, and commercial vessels. Turkish yards have fabricated steel vessels for decades. The critical factor - corrosion protection - requires independent supervision from day one.
Steel makes compelling sense for vessels above 18m intended for extensive offshore or commercial use. The material is cheap, universally available, and welds with ordinary equipment. Impact resistance is superior to any other common build material. A steel hull that strikes a reef does not hole - it deforms.
The disadvantage is weight and corrosion. A steel hull is 40-50% heavier than the aluminium equivalent. And steel corrodes in seawater. Protecting it requires sandblasting to Sa2.5 standard, an epoxy primer system applied within 4 hours of blasting, and epoxy topcoats. If this sequence is not followed precisely - and it frequently is not in unsupervised Turkish yards - the paint fails within 2-3 years and structural corrosion follows.
In 15 years of supervising steel builds and surveying steel vessels in Turkey, the single largest source of problems is incorrect paint application. The corrosion protection sequence must be: (1) abrasive blasting to Sa2.5, (2) epoxy zinc primer applied within 4 hours, (3) epoxy mid-coat, (4) antifouling topcoat below waterline. If humidity is above 85% during application, the entire sequence must stop.
We have surveyed steel vessels less than 5 years old with structural corrosion because this sequence was not followed. Paint system monitoring is a non-negotiable part of Surveyyat steel build supervision.
Abrasive blasting to ISO Sa2.5. Profile 50-75 microns. Applied within 4 hours of blast. Humidity below 85%.
Epoxy zinc phosphate primer, minimum 75 microns DFT. Interior: epoxy coal tar or 2-pack epoxy. External topsides: high-build epoxy.
Copper-containing antifouling above zinc anodes. Inspect and replace anodes annually. Haul-out minimum every 18 months.
| Vessel type | LOA | Steel build cost Turkey | vs Aluminium | Timeline |
|---|---|---|---|---|
| Steel Sailing Yacht | 14-18m | EUR 220,000 - 400,000 | 20-30% less | 10-16 months |
| Steel Motor Yacht | 14-18m | EUR 260,000 - 480,000 | 25% less | 10-16 months |
| Steel Expedition Vessel | 18-24m | EUR 400,000 - 800,000 | 30% less | 14-22 months |
| Steel Gulet-Type | 20-28m | EUR 500,000 - 1,100,000 | n/a (unusual) | 16-24 months |
| Steel Commercial Vessel | 18-30m | EUR 450,000 - 1,200,000 | Preferred | 14-24 months |
Steel builds include corrosion protection system in quoted cost. Supervision fee 2-4% of contract. Travel within Turkey included.
Mandatory for any steel survey. Readings taken at minimum 100 locations - hull bottom, topsides, deck, frames, and suspect areas. Identifies hidden corrosion not visible through paint.
Bilge water pools at frames. Internal corrosion at frame-to-plating connections is the most common critical finding in steel vessels over 10 years old.
Steel hulls are inherently conductive. Correct bonding system and anode protection prevents stray current corrosion - the most rapid and destructive form of steel hull deterioration.
Paint adhesion testing at multiple locations. Identification of blistering, delamination, and osmotic blistering. Assessment of remaining service life before repainting required.
We supervise steel builds with mandatory paint system verification at each stage. Pre-purchase surveys include ultrasonic thickness measurement as standard.