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CROSSING COASTAL RIVER BARS Disaster inbound Damage outboundHelp page Bar DynamicsDamage inbound Vessel handling (Ranger Hope © 2005/14) (Chart extracts.

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Presentation on theme: "CROSSING COASTAL RIVER BARS Disaster inbound Damage outboundHelp page Bar DynamicsDamage inbound Vessel handling (Ranger Hope © 2005/14) (Chart extracts."— Presentation transcript:

1 CROSSING COASTAL RIVER BARS Disaster inbound Damage outboundHelp page Bar DynamicsDamage inbound Vessel handling (Ranger Hope © 2005/14) (Chart extracts courtesy of AHO) Open as Ppt show

2 The NSW East Coast is renowned for its formidable river bars. Safe passage requires both the vessel and the skipper’s experience to be adequate for the conditions encountered.

3 All small vessels and all skippers have their limitations. If in doubt don’t go out

4 All small vessels and all skippers have their limitations. Never turn your back to a wave.

5 PORT MACQUARIE BAR DIAMANTINA ROCKS BARS OF THE NORTHERN RIVERS As the river water meets the sea it spreads out, slows and drops its load of silt. The East Australian Current continually erodes the seaward side forming a steep edge where waves can suddenly form.

6 THE PORT MACQUARIE BAR

7 PORT MACQUARIE BAR 2013 Diamantina Rocks EAST AUSTRALIAN CURRENT DAYTIME LEADS NIGHTIME LEADS VARIABLE LEADS - AVOIDS SOUTHERN HAZARDS 2013 approx 250º T 2013 approx 245º T 2013 approx West T 2013 approx 265º T Breaks This chart extract is not for navigation click here for charts

8 CAMDEN HAVEN BAR

9 This chart extract is not for navigation click here for charts

10 FORSTER TUNCURRY BAR

11 FORSTER TUNCURRY BAR This chart extract is not for navigation click here for charts

12 OTHER BARS

13 TWEED BAR This chart extract is not for navigation click here for charts

14 RICHMOND RIVER BAR This chart extract is not for navigation click here for charts

15 THE CASUALTIES OF PORT MACQUARIE BAR The Mermaid, the Prince Regent and the Lady Nelson were all damaged on the bar when they brought the first convict settlers in The “safe and commodious harbour…of a type familiar to experienced seamen of this coast” as promoted by the explorer John Oxley in 1818, has since claimed thirty more shipwrecks and countless small vessels.

16 Ben Boyds topsail schooner WANDERER On 14 th November 1851, in huge seas with 14 crew and 14 foot of draught, the rakish craft was spotted desperately searching for entry. The townsfolk fearing she was a pirate signaled warning not to cross the seven foot depth over the on the bar. The next day she foundered the seven foot depth as she attempted to run the bar.

17 In 1879 the outbound paddle steamer the Ballina was swept sideways where she stuck fast on the sand. Cargo and passengers were taken off but attempts to refloat her failed. The outer northern breakwall was built over her remains.

18 F.V. NERANGI In 1933, the attempts of the Pilot Master Capt. Liley were unsuccessful in towing the trawler off the Southern Breakwall. She became a total wreck.

19 Captain Liley considered the new double ender pilot boat the “Hastings” unsuitable for bar work. In 1937, while piloting the SS Nambucca inbound, a freak wave capsized her and he was drowned. Here she is seen washed up on the North Shore. His crewman, with a lifebuoy, Jim Fitchett, survived.

20 PORT MACQUARIE WATERFRONT IN 1890 THE EVER CHANGING BAR The signature of a bar is that it is always unpredictable, changing by act of man, nature or conditions of the moment. History shows that changes can be dramatic and sudden. Royal HotelThe BarClarence StKooloonbung Ck

21 Royal Hotel THE SWASHWAYS OF THE BAR Goal Point Copy of an original painting courtesy of the Hastings Council Art Collection

22 PORT MACQUARIE THE SWASHWAYS OF THE BAR BALLINA WRECK ROYAL HOTEL WANDERER WRECK

23 NORTH SHORE NORTHERN BREAKWALL BALLINA WRECK SOUTHERN BREAKWALL PELICAN ISLAND ROYAL HOTEL CLARENCE ST WHARF RESCUE SHED RSL THEN AND NOW SHORELINE OVERLAID BAR

24 PORT MACQUARIE

25 1943 In 1929 a one hundred year flood washed away the North Shore, the new entry was shoals & shallows until consolidated by the Northern Breakwall constructed in Ballina Channel Southern Breakwall 1899

26 Ballina channel PORT MACQUARIE 1970

27 PORT MACQUARIE 2004 Outer Northern Breakwall By 1970 sand build up on the North Shore has reduced the bar to 5 feet. In 1976 the outer Breakwall was built to create northerly sand migration and push a crescent bar out to sea. The wreck of the Ballina and the Ballina Channel were covered by the new wall. By 2000 swell was often found to be less heavy to the north of the charted (recommended) track sown above. This chart extract is not for navigation click here for charts

28 The Crescent Bar Flagstaff Hill PORT MACQUARIE 1984

29 PORT MACQUARIE 1998 The Crescent Bar

30 BARS ARE EVER CHANGING Advice received must be weighed against your observation of present conditions PORT MACQUARIE 1998

31 PORT MACQUARIE BAR 2013 Diamantina Rocks EAST AUSTRALIAN CURRENT DAYTIME LEADS NIGHTIME LEADS VARIABLE LEADS - AVOIDS SOUTHERN HAZARDS 2013 approx 250º T 2013 approx 245º T 2013 approx West T 2013 approx 265º T Breaks This chart extract is not for navigation click here for charts

32 THE DYNAMICS OF RIVER BARS Swell Wind Seas Current TideFlood EVER CHANGING BAR CONDITIONS

33 Ocean waves rotate within their wavelength. Squeezed upward on the shoaling bar, they slow down, the wavelength shortens and they may become top heavy and break. They become waves of translation (pushing forward). WAVE ACTION ON THE BAR 18 knots on the bar 25 knots approach25 knots after The bar Steep edge The seaward edge is kept steep by the East Australian Current. Typical speeds of the swell Lagoon

34 Seas Swell Wavelength Sea and swell coincide SWELL AND SEAS Seas are whipped up by the local wind. Swell is created by distant storms, persistent winds or seismic events. Seas + swells of different frequencies interact to form sets. Typically 50 to 200mtrs Speed knots

35 SWELL AND SETS CORAL SEA CYCLONE LOW IN THE TASMAN Swells of different frequencies may interact to form sets of larger waves or lulls. The period between sets may be up to 20 minutes or more.

36 EFFECT OF WIND ON THE BAR Increase of wavelengths and breaking of waves flattens waves inshore, but raises them offshore Swells slow down and their wavelengths shorten on the bar Offshore wind Onshore wind

37 EFFECTS OF ONSHORE WINDS More white water Higher waves, longer swell More spray, less visibility

38 EFFECT OF TIDE ON THE BAR Increase of wavelengths & progressive increase of bar depth shortening of wavelengths & raising of wave height Swells slow down and their wavelengths shorten on the bar Ebb tide Flood tide

39 PORT MACQUARIE 2004 The Crescent Bar 2004

40 PRESSURE WAVES Strong run out tide can create standing waves by shortening the wavelengths and raising of wave height. These are usually inside the bar but particularly “wet” for small vessels to cross.

41 RUN OUT & FLOOD Northerly longshore current Southerly East Australian current The overflowing saucer effect of run out

42 South West Rocks Southerly swell offshore The leading edge of swells slow as they hit shallow water causing waves to land parallel along the beach. Northerly waves into Arakoon Arakoon Easterly waves in the break COASTAL REFRACTION

43 SE on the South Easterly on the leads NE on the North Refraction on the crescent bar moderates swell direction.

44 THE REGULATIONS Commercial vessels require operational permit and are ill advised to operate on bars in conditions above winds of 20 knots and waves of 2 metres In approved lifejackets (PFD1) must be worn over bars Disaster inbound Damage outbound Photos courtesy of RMS

45 FAST PDV OUTBOUND PLAN Prepare your vessel and crew Forecast, fuel, mechanics, stowage, Pfd 1 Watch and wait Lulls and Sets may be 20 minutes apart Radio an ETR Tell someone where you are going Look for saddles of lower wave height and avoid white water. Anticipate tackling at least three waves on the bar & don't turn around. Slow down to reduce the impact forces of the swell HIIGH TIDE & RUN IN TIMING IS EVERYTHING DON’T GET AIRBORNE ASSUME NOTHING

46 Show me how not to exit a bar Swells may travel at 25 knots. A vessels approach at 20 knots creates an impact at 45 knots. You cannot slow the swell. Becoming airborne results in damage to vessel and crew. Slow down to reduce impact forces Show me a small vessel outbound Photos courtesy of NSW Maritime Authority

47 PREPARE YOUR VESSEL TO GO OUT POOR TRIM GOOD TRIM Overloading aft encourages becoming airborne, level trim punches through the waves. LOW MOTOR TILTGOOD MOTOR TILTHIGH MOTOR TILT Poor tilt trim encourages becoming airborne or punches under the waves.

48 SLOWER VESSELS OUTBOUND Show me a large vessel outbound

49 AVOIDING THE WORST OF THE RUN OUT PRESSURE WAVES Show me a Parallel running exit This technique is only relevant to Marine Rescue Personnel who may be required to exit in unfavourable conditions in order to save life. If you need to use such methods to get out then you shouldn’t go out!

50 INBOUND PLAN -ASSUME NOTHING Don’t turn around HIIGH TIDE & RUN IN TIMING IS EVERYTHING Stay on the back of the wave Watch and wait Lulls and Sets may be 20 minutes apart Prepare vessel and crew Forecast, fuel, mechanicsl, stowage, Pfd 1 Radio sign off on return Tell the rescuers that you are back Disaster inbound

51 No water flow over the rudder whilst surfing down the wave face. Ineffective prop thrust due to cavitation in the aerated white water. The stern being pushed forward by the wave crest as the bow bottoms in the contra-rotating trough. BROACHING IS PROMOTED BY : NEVER RUN DOWN THE WAVE FACE as it slows on the bar Stay on the back of the wave

52 PREPARE YOUR VESSEL TO COME IN POOR TRIM GOOD TRIM Slight trim by the bow up, improves buoyancy and stops the bow digging into the holes. TOO LOW MOTOR TILTLOW MOTOR TILTGOOD MOTOR TILT

53 Sight an object or compass bearing as the river mouthmay disappear behind the wave. STAR CLOUD COMPASS BACK OFF THE REVS IF WHITE WATER CAVITATION OCCURS Gently reapply only the power at which the prop will grip the water. Stay on the back of the wave

54 PRESSURE WAVES Dealing with pressure waves inbound

55 Prepare for heavy weather, Pfd 1 Stowage & free surface effect limitation Watertight doors, deadlights & hatches Clear freeing ports Consider a drogue DON’T TURN AROUND SLOWER VESSELS INBOUND Tell me more about preparing for heavy weather Photos courtesy of RMS

56 SHOULD YOU WAIT UNTIL CONDITIONS IMPROVE? SLOWER VESSELS INBOUND Photos courtesy of RMS

57 PORT MACQUARIE BAR TOWING OPERATIONS

58 ADVICE & HELP IS AVAILABLE FROM YOUR LOCAL SEA RESCUE TELL THEM WHO YOU ARE AND WHEN YOU EXPECT TO BE BACK Many volunteer rescue units maintain a radio watch and operate safety schemes for protecting vessels in their area.

59 AUSTRALIAN HYDROGRAPHIC OFFICE CHARTS The sample of chart AUS 219 is not safe for navigation but for demonstration only. Accurate charts are available from: BUREAU OF METEOROLOGY SATELLITE WEATHER COLOUR NSW MARITIME RMS 4 DAY FORECAST TIDAL PREDICTIONS MORE HELP IS WAITING AT: Aus 219 FOSTER TUNCURRY CAMDEN HAVEN HASTINGS RIVER WEATHER WATCH LOCAL CONDITIONS RESCUE TIDES PORT MACQUARIIE SEA RESCUE MARINE RESCUE NSW AUST. VOLUNTEER COASTGUARD ROYAL VOL. COASTAL PATROL

60 IF IN DOUBT Now check your progress Ranger Hope © 2004 Courtesy of Port Macquarie Newspapers

61 END


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