Can Grace safely enter Noosa, and what depth and tide limits should I plan for?

Grace can enter Noosa safely only if her loaded draught, the latest minimum depth on the entrance route and the swell conditions allow it. Plan a daylight crossing on a rising tide with confirmed clearance; this shifting sand bar has no dependable permanent depth limit.

Check Grace's loaded draught

Measure from the waterline to Grace's deepest fixed underwater part, with cruising stores, fuel and water aboard. Her name alone does not identify her hull, keel or draught. Another yacht's figures cannot tell you whether she will fit.

• Fixed-keel yacht: use the loaded keel draught, allowing for uncertainty in the published specification.
• Lifting-keel yacht or trimaran: check the rudder, propeller and drive leg as well as the raised keel or centreboard. Establish how much board must remain down for control.
• Motorboat: use the deepest operating position of the running gear; trimming a drive up may reduce steering and thrust.

Check the sounder offset too. Depth below the transducer, total water depth and clearance below the keel are different readings. Establish which the sounder displays before approaching shallow water, rather than trying to interpret an alarm in the entrance.

Calculate the minimum tide height

Noosa's entrance is a mobile sand channel. A charted sounding, an old track or another skipper's successful passage cannot establish today's least depth. Obtain current advice from the local marine rescue service. Before departure, check Maritime Safety Queensland notices, available entrance surveys and coastal observations.

For preliminary planning, use this calculation only when the bottom depth and tide height share the same datum:

Minimum tide height = loaded draught + required clearance − minimum bottom depth below chart datum.

For example, if Grace draws 1.80 m, the latest reliable minimum bottom depth is 1.20 m below chart datum, and you select 0.80 m clearance, the calculated minimum tide height is 1.40 m. These figures illustrate the calculation; they are not reported Noosa depths or an entry recommendation.

If someone reports "2.5 m through the channel", establish when it was measured, the tide height then and whether the figure was total water depth. Adding today's tide to an observed total depth would count the tide twice.

For initial screening, allow at least 0.5 m static clearance in sheltered water and consider 1.0 m or more where swell affects the crossing. Neither figure guarantees safety. Pitching, wave troughs, squat and uncertain soundings can consume that margin. Breaking conditions can rule out entry regardless of depth.