Thanks chaps. Yes Fenlander, you correctly pull me on my somewhat novice approach to naval navigation. That first outing was quite a learning experience in terms of cross referencing depth on sounder, charts, watching what the water was doing, land features, etc. So much to observe and interpret.
My concern, aside from grinding to a sudden halt and getting stuck, was what impact the mud ingestion could/would have on the engine... Sounds perhaps like this is the least of my worries.