Date: 201510
Local time of day: 0601-1200
Location: BOS.Airport, MA
Flight conditions: VMC
Light: Dawn
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
ATC / advisory: Tower BOS
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Training / Qualification; Situational Awareness
Second reporter function: First Officer
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
Detector: Person Flight Crew; Person Air Traffic Control
When detected: Taxi
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Contributing factors: Procedure; Manuals; Human Factors
Primary problem: Ambiguous

Narrative: We were too heavy to launch off 22R so coordinated for takeoff on 22L. As we pulled onto the runway; we noticed a multi-deck cruise ship passing east to west and just past the extended centerline of 22L. Tower told us that the vessel had a 175 ft mast height and was some distance (I don't recall the exact numbers) from the departure end. As the ship was west of the runway centerline and moving west; we elected to launch. After climbout; we reviewed the performance data to see what the effect would be if the ship hadn't been moving but instead had been stationary off the end of the runway. We saw that the obstacle climb would have been limiting and that we would have been too heavy to launch from 22L. The performance data also has a '22L Ship Condition' option on the runway selection page. However; we could find nothing about what ship condition means or whether the Tower-provided obstacle data overrides the use of ship condition. There was nothing on the ATIS or in the NOTAMs for BOS that mentioned tall ships of the end of the runway possibly because; since the ship was moving; useful data would have been hard to provide.In retrospect; we should have pulled off the runway; run the numbers Tower provided for obstacle data; and then queried the Tower as to when they showed the ship was no longer an obstacle. Alternatively; we could have coordinated takeoff on 15R; which we might have been able to get. We need better documentation about tall ship departures at BOS. The airport pages for BOS should add a discussion of tall ship procedures in the Departure section to include when to use the '22L Ship Condition' option of the performance data. BOS Tower should issue a NOTAM for tall ships in the harbor when 22L/R are in use; with at least an approximate effective time.


Second narrative: Prior to takeoff from Runway 22L; we were advised by Boston Tower that a cruise ship had entered the harbor. Went to recalculate data with ship obstruction and found that we were too heavy to depart and waited for cruise ship to clear the departure path. We became concerned how far away from runway centerline the cruise ship has to be to be legal to depart without having to use the ship obstruction criteria. We could not find any guidance on the performance Computer or any manual. Publish definitive guidance on the ship obstruction when departing Boston.


Synopsis: B737 flight crew is informed by BOS Tower of a ship in the harbor while preparing to depart Runway 22L. They were too heavy to depart with 'ship in harbor' performance data and waited for the ship to clear the runway centerline and departed. Airborne; the crew wondered if merely clearing the runway centerline was sufficient to meet the 'no ship' performance criteria.