Hello John
cremore lagoon is accessed down Honeywood drive ( it is on your left as you go down the South Arm hwy. Has to be southerly - south east to sail here.
Mortimer bay and dorans road ( ralphs bay) are different spots. Dorans is sailed in nw to sw. Mortimers is more south- south west.
All three places are shallow and easy places to sail and within 5 minutes of each other. Wear booties as oysters are nasty on bear feet!
PS. Mortimers is a lumpy track accessed off Gellibrand drive.
Jez can be your tour guide if you need one , part of the package!!

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