Vol 1, Sixteenth Edition of Sailing Directions, British Columbia Coast (South Portion) - an official publication has this to say about Dodd Narrows:
Dodd Narrows is more difficult to pass through when entering from north rather than south, for in the former case, the slight alteration in course, necessary when passing through, has to be made immediately on entering the narrow part; in addition the entrance to Dodd Narrows is difficult to see when approaching from Northumberland Channel.
It is recommended that passage through Dodd Narrows be made at slack water. Before passing through Dodd Narrows other than at slack water be sure the vessel is able to proceed against the tidal stream; if there is any doubt, passage should be delayed until slack water.
Note: I have yet to transit Dodd Narrows unevenfully - invariably yahoos in larger powerboats making huge wash being amplified by the current - always plenty of venting on VHF.
cheers - Dave