Hi black_jack mate he is right on that comment if you look in the rules an regs of boating it states the size an weight of anchor, Chains and different diameter of rope or if the vessel is to use full chain required for the different size vessel once a vessel reaches a certain size they must go into the plough anchors for safety reasons but we should always carry the right anchors on board as you never know just when you may require the different anchors i always carry a sandy an my reefie when i am outside or in the bay if at the pin the reefie is left at home so as it does not get in the way an i have both 50mtr an 100mtr of rope and 3 mtrs of chain on both anchors or if going to tipplers or some where the same for camping i always carry two sandies so as to place the nose of the vessel out so the big bay cruises do not flood them from the stern or they do not beach themselves
hope this helps and answers your question
Cheers
Steve