Uneven and missing marine chart data

[speleoluc]

When I navigate my kayak with Osmand+, I choose a Kayak profile that uses the Nautical map view plugin. Yet I seldom see buoys on my maps, and I don't recall ever seeing a water depth, nor the Saint Lawrence Seaway, a major commercial navigation route that has been excavated, thus deeper than its surroundings. Am I mistaken on Osmand's scope, do I need another plugin or subscription or is it just a data shortage for my area (Quebec, Canada) in OSM sea maps?