WBC3 Area Categories Explained — Cat 0 to Cat 6
Every workboat certified under WBC3 is assigned an area category of operation. This determines where the vessel can go, what equipment it must carry, and what qualifications the crew need. Getting the right category matters — too low and you're limited in where you can work; too high and you're carrying equipment and qualifications you don't need.
Key points:
- Seven area categories from Cat 0 (unrestricted) to Cat 6 (within 3nm, daylight only)
- Higher categories require more equipment and higher crew qualifications
- Most UK harbour workboats operate at Cat 3–6
- Vessels can operate at a lower category than their certificate allows
The Seven Categories
| Category | Operating Area | Conditions |
|---|---|---|
| Cat 0 | Unrestricted | No distance limit |
| Cat 1 | Up to 150nm from a safe haven | Offshore operations |
| Cat 2 | Up to 60nm from a safe haven | Extended coastal |
| Cat 3 | Up to 20nm from a safe haven | Near coastal, day and night |
| Cat 4 | Up to 20nm from a safe haven | Daylight only |
| Cat 5 | Within 3nm of land | Day and night |
| Cat 6 | Within 3nm of land, max 3nm from departure point | Daylight only, favourable weather |
One thing that confuses operators: Cat 3 and Cat 4 cover the same distance — 20 nautical miles from a safe haven. The only difference is Cat 4 is restricted to daylight. This matters more than you'd think, because it affects crew qualifications. RYA Day Skipper is acceptable as a Master qualification for Cat 4 (daylight) but not for Cat 3 (which includes night operations). If you might ever need to operate after dark, you need Cat 3 — and that means a higher Master qualification.
Similarly, Cat 5 and Cat 6 both cover 3 nautical miles from land. But Cat 5 allows night operations and Cat 6 doesn't. Day Skipper is valid for Cat 6 but not Cat 5. The distance is the same — it's the daylight restriction that changes everything.
What Changes Between Categories?
Equipment
Higher categories require more and better equipment. For example:
- Liferafts: Required for Cat 0–5. Cat 6 vessels in certain conditions may be exempt.
- EPIRB: Required for Cat 0–3 and Cat 5.
- Radar: Generally required for Cat 0–2. Optional for Cat 3–6 unless fitted.
- GMDSS radio: The type and capability of radio equipment increases with category.
Crew Qualifications
The minimum Master qualification varies significantly:
- Cat 0: STCW Master or Yachtmaster Ocean
- Cat 1: Yachtmaster Offshore
- Cat 2–3: Yachtmaster Coastal, Boatmaster Licence, or Powerboat Advanced
- Cat 4: Day Skipper (daylight only) or Powerboat Advanced
- Cat 5: Powerboat Advanced (Day Skipper is NOT valid — Cat 5 includes night operations)
- Cat 6: Powerboat Level 2 (restricted to open boats/RIBs under 3GT), Day Skipper, or above
The second person requirement also varies — Cat 0 and Cat 1 require a specifically qualified second person (Yachtmaster Offshore for Cat 0, Yachtmaster Coastal for Cat 1). For Cat 2, the Master decides if the second person is competent. For Cat 3–6, it's the owner/operator's judgement — no specific qualification is needed, just someone they consider experienced and competent.
Watch out for Powerboat Level 2. Under the old MGN 280, PB Level 2 was accepted for vessels up to 24m. Under WBC3, it's restricted to Category 6 only, and only on open boats, RIBs, or inflatables under 3 gross tonnes. If your vessel doesn't meet those conditions, PB Level 2 is not a valid Master qualification — regardless of whether it has a commercial endorsement.
Construction
Higher categories have more stringent requirements for structural strength, stability, and watertight integrity.
Operating Below Your Category
A vessel can always operate at a lower category than the one it's certificated for. If your vessel holds a Cat 2 certificate and you're making a trip that falls within Cat 4 limits, you can use Cat 4 manning and equipment requirements for that voyage.
This is useful for vessels that occasionally make longer passages but mostly operate closer to shore. For example, a Cat 2 vessel making a short harbour run doesn't need to carry all its offshore equipment for that trip — it can operate under Cat 5 or Cat 6 requirements for the voyage. But the reverse isn't true — a Cat 6 vessel can't make a Cat 2 trip without being re-certificated.
Choosing the Right Category
Most operators should certificate for the category that matches their normal operational area:
- Harbour workboats doing short daylight trips within a port → Cat 5 or Cat 6
- Coastal workboats doing crew transfer, survey, or support work within 20nm → Cat 3 or Cat 4
- Offshore vessels working wind farms, oil and gas, or long coastal passages → Cat 1 or Cat 2
Getting a higher category than you need means carrying more equipment and holding higher qualifications — which costs more. Getting a lower category means you can't take jobs beyond your limits without re-certification.
Your Certifying Authority can advise on the right category for your operation.
Read next: WBC3 Crew Qualifications — What Your Crew Actually Need →
Sources: WBC3 Sections 3.10, 28.1.3. Tables A5.1, 14.1.2.