Anchoring in Desolation Sound is no different than anchoring anywhere else. Many of my favourite anchorages are in that region and we do go often but not during the peak summer season. Check your charts for the anchorages that you plan to visit and decide on your ground tackle based on the depths, tides, sea bottom and exposure to wind. The good news is that, for the most part, anchorages in Desolation are protected from large fetch (coves, inlets, harbours). Winds are normally calm but you should be prepared otherwise. The bad news is that tides can exceed 17' (15.5' at 6 AM this morning) so 30' becomes 45'+ at high tide. And it does get congested (to read very congested) during the summer months so you will benefit by staying put with chain rode. The shallower areas are usually reserved for boats with shallow draft and/or those that do not mind anchoring very close to others. And yes you will have to get there really early or move to a better spot the next day. Popular anchorages are Prideaux Harbour (40' plus tide 55'), Von Donop Inlet, Grace Harbour and Squirrel Cove (30'/45') and Drew Harbour (60'/75'). There are many, many others that may require creative anchoring techniques (Tenedos Bay) and of course stern tie. FWIW, I have 200' 5/16" G4 and 250' 5/8" nylon 3 strand anchor line with a 15kg \Manson Supreme on a boat with a displacement of 12,500 lbs. I usually anchor with a scope of 3 (plus a little) and only occasionally am I into the anchor line. Average I would guess would be 150' to 180'.