John We are currently at the eastern side mooring wall (8'6" depth) at Poonamalie Lock 32 on the Rideau heading south so can only tell you what we've experienced from Ottawa to Poonamalie (north of the Rideau Lakes). We have a 4'8" 'official' draft trawler with 18' beam and 16'6" air draft. With full tanks and full provisioning in fresh water we estimate that we are much closer to 5' draft. We have seen 5'6" of water in a couple of places in the channel and we are particular about honoring the markers and watching both of our electronic charting systems. We generally see a minimum of 6' of water in the channel. You will regularly see 6' in the channel coming close to a lock and we see 6' on our depth sounders going over the lock sills. It is difficult for Parks Canada to give you a exact answer as the water levels do fluctuate and receed with rainfall. In the section north of Poonamalie Lock at the moment the water level is just 2 inches above chart datum. The thing we dislike most is the amount of weed in the water. If you decide to take the Rideau Canal and intend mooring at the Parks Canada docks/mooring walls we suggest you check with the lock staff about water depth at the walls prior to attempting to dock. At Kilmarnock Lock we found the maximum water depth alongside the east and west walls to be 3'9". Having said that most of the mooring walls have 6' plus alongside. Most of the boats we have seen on the Rideau so far we would classify as 'small boats', a lot of 32'-36' Carver type shallow draft go fast boats mostly locals. Maybe the 'bigger' boats will come along later in the season ? The Parks Canada staff have all been overwhelmingly helpful. Unless you are in a hurry we would suggest you sit out the weekends somewhere as the local traffic can get pretty hectic but during the week so far we've had most of the mooring walls and locks to ourselves. We're sure that will change come July. At 5' we would say like us you are pushing the limit in a few spots but so far we've not encountered anything to really scare us. There is also a Nordic Tug 37 who has gone ahead of us with a similar draft. Apparently a barge and a tour boat come through here regularly during the season and both have a 5' draft. So far we think it's certainly been worth the effort but it depends on your tolerance to just giving things a go and see what happens. Regards from Rod and Pauline 2003 Nova Scotia 47 Pilothouse Trawler