Both vessel types are offshore support vessels. The daily work, required skills and pay differ enough that experienced officers who have done both consistently describe them as different careers.
What Each Does
PSV: runs cargo between shore bases and installations. The defining operation is DP cargo transfer near rigs and platforms. Carries deck cargo and bulk liquids. Transits, arrives, works, returns. Repeat.
AHTS: does the supply work but adds anchor handling. When a semi-submersible drilling rig moves location, AHTS vessels recover the anchors, attach towlines, move the rig and reset the anchor pattern. The anchor handling work is in a different operational category from supply runs.
The Physical Difference
PSVs are designed around deck cargo capacity. The power plant supports DP but the vessel is not built around raw towing force.
AHTS vessels are built around power. Bollard pull is a primary specification. Large North Sea AHTS vessels have bollard pulls of 200 tonnes and above. The winches are enormous. This requires substantial engine power and the vessels are larger and more powerful than most PSVs.
The Skills
Both require DP certification for watchkeeping officers. Anchor handling on AHTS vessels requires additional competency built through sea time and company-specific training. AHTS deck officers develop heavy lift operations, towline management and anchor pattern skills that PSV officers do not routinely work with.
AHTS experience is distinctive on a CV in a way that straightforward supply vessel experience is not.
Pay Comparison
North Sea monthly rates.
PSV Chief Officer: $9,000 to $13,000 AHTS Chief Officer: $10,500 to $15,000
PSV Master: $11,000 to $16,000 AHTS Master: $13,000 to $19,000
The AHTS premium reflects more demanding operational requirements and a smaller pool of qualified officers with relevant experience.