Local Knowledge

This book contains an eclectic assortment of valuable navigation tools including over 50 pages of handy distance tables between West Coast ports and anchorages for navigation planning and strategies for managing the tides and currents in Johnstone Strait and Cordero Channel set out in an easy-to-use tabular format.

It also contains conversion tables, time, distance and speed tables, weather reference data, radio procedures and frequencies and a number of useful information resources to answer many of the questions that come up while underway. Compiled by Kevin Monahan, an officer in the Canadian Coast Guard and former fisherman and delivery captain, this book provides the local knowledge to simplify navigation and safe passage from Tacoma to Ketchikan.

Distance	On an overcast day with at least 5 miles visibility	On a sunny day
1/2 cable 0.05 Nm. 300 feet	Differing types of bushes clearly distinguishable Ferns identifiable. Texture of tree trunks can be seen clearly. Blades of grass can be seen.	Differing types of bushes clearly distinguishable Ferns identifiable. Texture of tree trunks can be seen clearly. Blades of grass can be seen.
1 cable 0.1 Nm. 600 feet	Individual leaves visible on deciduous trees and bushes. Coniferous branchlets visible. Different types of vegetation not distinguishable. Grass appears fuzzy.	Individual leaves visible on trees and bushes.Coniferous branchlets visible. Different types of vegetation not distinguishable.Grass appears fuzzy.
2 cables 0.2 Nm.	Conifers--small branches appear.	Conifers--small branches appear.
5 cables 0.5 Nm.	Conifers--large branches clear and distinct. Texture of deciduous bushes apparent, showing lighter green than conifers	Conifers--large branches clear and distinct. Dead branches on conifers visible
7.5 cables 0.75 Nm.	Conifers--large branches becoming distinct.	Conifers--large branches becoming distinct. Texture of deciduous bushes apparent, showing lighter green than conifers
1 Nm.	Conifers--large branches barely visible. Deciduous--large branches distinct.	Conifers--large branches barely visible. Deciduous--large branches distinct.
2 Nm.	Deciduous--texture of branches and leaves clear but individual large branches not visible	Individual conifers clearly visible. Deciduous--texture of branches and leaves clear but individual large branches not visible
2.5 Nm.	Trees dull green. Individual trees just visible.	Individual dead conifers just visible. Individual trees just visible.
3 Nm.	Deciduous trees apparent by cloudy texture and lighter colour. In winter they appear like smoke.	Coniferous forest has a textured appearance. Individual trees barely distinguishable except on the skyline. Deciduous trees apparent by cloudy texture and lighter colour.
4 Nm.	Trees take on a bluish appearance. Individual trees not distinguishable except on skyline, but texture of forested areas is apparent.	Individual trees not distinguishable except on the skyline.
5 Nm.	Texture of forested areas is just visible.	Trees a dull green. Individual trees not distinguishable except on skyline, but texture of forested areas is apparent
more than 5 Nm.	Texture of forest not readily apparent. Objects at sea level are below the horizon to an observer on a small boat. Individual trees on skyline not detectable.	Texture of forest not readily apparent. Objects at sea level are below the horizon to an observer on a small boat. Individual trees on skyline not detectable.
This table applies only to observers with good eyesight when atmospheric conditions are favourable. The distances quoted are estimates only and the criteria are quite subjective. Use the table with caution. It is intended as a guide only.