Factors to consider when deciding on weather routeing?
- Voyage length
- Navigational viable (free from land)
- Free from strong currents, ice, load line restrictions
- Most beneficial in when extreme weather expected
- Type of vessel
What can be the different objectives of weather routeing?
- Least time track
- Least time with least damage to hull
- Least damage
- Constant speed
- Fuel saving
- To avoid ice accretion
Method of obtaining a Least time Track (this is from the Stone Age), it’s all automated on computers now. But when SQA exams say jump we say how high
- From a start point identify a rough area where least time area will occur.
- Create multiple possible routes
- Using performance curves, expected wave height chart and synoptic chart overlays approximate expected sailing time for 24 hours
- Repeat process and identify least time track
Types of message from Weather Routeing company?
- Advisory Message, forecast significant and unavoidable
- Diversion Message, forecast significant and avoidable
What is a Hindcast Chart?
- A way of comparing a vessels track and actual weather experienced compared with alternative routes and weather.
- Shows time, fuel and money saved
- Produced by weather routeing companies for vessels
Benefits of carrying out Shipboard routeing?
- Cost saving - however increased workload for officers
- Modern ships have access to a lot of similar weather information that a weather routeing company has.
- Ship’s crew can better assess current weather then forecasts
- Master has experience on how his vessel performs in differing conditions
Factors for Master to consider when choosing optimum route?
Climatic / Operational
- Currents
- Encountering fog or ice
- Delays or damage to due to adverse weather
- Type of ship, nature of cargo
- Operational tasks required on passage
Commercial
- Instructions from owners or terms of charter party
- Dist of each route
- ETA and fuel consumption
- Time saving / delay and costs of canal
- Load Line Zones
What is Climatic Routeing?
- Following recommended routes according to season for a given ocean
- Shows average prevailing conditions from years of data
- Illustrated in Ocean passages for the world and routeing charts
What to refer to when considering factors for planning ocean passage?
- Ocean current circulation
- Worse weather in high lats
- Better weather in middle lats (STAC)
