Fastnet Navigation

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Fastnet Navigation

• Nat Ives - RORC May 5 2009

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AGENDA

• Aim of the course
• The role of the navigator offshore
• Pre-race prep
• On the race track
• Routine and log
• Competitor tracking
• Weather and strategy updates
• Performance monitoring

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Role of the offshore navigator

• Course to Sail
• Strategy
• Competitor tracking
• Sailing Instructions
• Notice of Race
• Rules
• Protests
• Instruments
• Performance data
• Start and nav software

• Weather
• Tides or currents
• Class regs
• Safety regs
• VHF comms
• Crew Weights
• Sail crossovers
• Sail hours
• Hazards
• Shipping (lights)

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Pre-Regatta Prep - Admin

• Notice of Race
• Governing Rules esp. Weather sources IRPCS
• Programme
• Race Course
• Registration
• SIs
• Reporting
• Time Limits
• Penalties esp OCS (two-turns penalty allowed,
  50 place for OCS)
• VHF and SSB channels
• YC facilities
• Start and End Where are you berthing?

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RORC Comms Regulations

• 5(d) VHF AND RADIO COMMUNICATIONS (SEE ALSO 6(b))
• Sailing Instructions may request yachts to send
  position reports during a race. There is no limit
  on communication from a yacht provided the yacht
  does not receive information (other than that
  publicly available to all) which might help her
  in the race see RRS41 - (outside help). A yacht
  may receive information about severe weather
  without infringing RRS41 (outside help).

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Pre-Regatta Prep the Race Track

• Waypoint lists for route, hazards, and lights
• Weather
• Forecasts sources - GRIB Files
• Live Data
• Historical Data - climatology
• Topography
• Roadmap?
• Tides or Currents
• Reference ports
• Sources of data e.g. SHOM
• Charts
• Check up to date
• Know symbols
• Create a daily timetable based on the above, run
  preliminary routes to highlight key points of
  race area

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Waypoints other than obvious headlands

• Start and Finish lines
• Shambles (EW)
• Eddystone
• Runnel Stone
• Longships
• Wolf Rock
• Seven Stones (light and rock)
• Scilly Isles outlying rocks
• Bishops Rock
• Weather stations (Channel Light Vessel and Air
  Strips etc)

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Climatology e.g.Culdrose vs Scilly
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GRIB Files

• Electronic compressed data file with forecasted
  or actual data on a grid
• Important to know
• Source compare models
• Forecast time and publish time usually in UTC
• Resolution (1 deg, 0.5 deg, or hi-res)
• Data height normally 10m
• How the data is calculated and displayed beware
  interpolation
• Sources
• www.grib.us (free 1 deg and 0.5 deg GFS/AVN data)
  check spaghetti plots
• www.saildocs.com (free 1 deg data)
• Higher res data is normally paid for e.g. Theyr,
  PRO-GRIB etc if paid for then NOT in public
  domain so illegal for RORC races after start
• www.predictwind.com
• http//www.opc.ncep.noaa.gov/grids/data/ Quik
  Scat analysis GRIBS
• Global GRIB data can overestimate early and late
  in the day, does not account for topography and
  sea breeze
• Check reference height for data normally 10m
• UKMO and MeteoFrance do not do free GRIB so use
  graphical output as reference

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Bermuda Race Daily Schedule

• UTC
• 0630 3 Day Basic Sat Analysis
• 0700 Posns
• 0830 Avn Model
• 1100 Gulf stream Sat Pic
• 1200 Daily SSB Broadcast
• 1230 3 Day Basic Sat Analysis
• 1430 AVN Model
• 1500 Posns Quikscat
• 1830 3 Day Basic Sat Analysis
• 2030 AVN Model
• 2300 Posns Gulf Stream Satellite Pic
• 0030 3 Day Basic Sat Analysis
• 0230 AVN Model Quik Scat

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Live Data Sources

• Use to update forecast and track features
• www.xcweather.co.uk
• UKMO
• University of Wyoming - http//weather.uwyo.edu/su
  rface/meteogram/
• CEFAS WaveNet buoy data
• Satellite imagery good for fronts
• MCA VHF broadcast Franks Weather pages
  weather.mailasail.com
• YOU!! And a your instruments - barometer

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Pre Race prep the boat.

• Instruments, GPS, Radar, Comms
• Calibration (depth etc) Operation (MOB
  Procedure, target tracking, charts, sunrise etc)
• Spares
• Polars and Sails
• Nav polars
• Sail Crossovers
• Nav equipment
• Compass Binoculars
• NavNotes Log
• Checklists
• Charts
• Almanac Tidal Stream Atlas

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The Polar Curve

• Mathematical model of performance, Boatspeed vs
  TWA, TWS
• Designers tool, modified with real sailing
  data
• Varies according to local conditions and
  situation
• Consider bumps in curve

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Polars

• Tie them in with Sail Crossover chart
• Think about VMC options.
• Check actual performance againstpolars all the
  time.
• VMC heavily affected by sea state
• Is TWS at masthead
• what is GRIB ref height?
• Is polar for masthead height?

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Optimum Route Planning

• Theoretical route that is fastest to the finish
  based upon
• Weather forecast (GRIB)
• Polars
• Current (GRIB or Database
• Cautions
• Only as good as your inputs
• Try to judge the sensitivity of the route by
  running with slower polar or shorter forecast
• Can be driven equally by last day of forecast as
  much as first (where as forecast is more reliable
  for early on)
• Use gut feel to estimate route first

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Optimum Route Planning
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A
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Tidal Route Farr 80 Swan 45 Ker 32
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Tidal Route Ker 32 TWD, TWS (base 230, 10kts)
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Sources of Tidal Data www.wileynautical.com
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Sources of Tidal Data

• Winning Tides Solent
• UKHO and SHOM data for Channel and Irish Sea
• Wiley Nautical Almanac

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During the race

• If you can be out of watch system then you can
  set your own routine. Link with tactician/skipper
  at key times to decide on course to steer.
• Convey course to steer with context e.g. Sea
  state etc, likely changes in conditions and sail
  changes. When you need to be called
• Re-run routing after each forecast and update
  using observed conditions and satellite imagery
• Track competitors online, visually or with radar
  (note bearings at dusk). Use this to help with
  forecast through implied winds.
• Track performance of boat against predictions and
  adjust navigation polar accordingly or if you
  loose a sail.

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Fastnet Navigation

• Nat Ives - RORC May 5 2009