You are wise to put nav lights on your boat.
The Safe Boating Guide (
https://publications.gc.ca/collectio...-2011-eng.pdf0)
says you just need " One (1) all-round white light; and • Sidelights" for a power boat under 39'4" (12m).
as an alternative to "• One (1) masthead light;
• OPtiOnaL — Another masthead light;
• Sidelights; and
• One (1) sternlight"
would be overkill for a 12' tin boat.
For my 14' hunting boat I use the Atwood clamp on AA battery powered LED combined red/green bow light (for the sidelight requirement) and clamp on all-round stern light, available at CTC.