Yes, you can build with strips shorter than your canoe. Think about it... the HMS Beagle wasn't built with 90 foot planks. Allow us to share our method of making scarf joints between building forms on the fly. One more tip... when using NWC pre-cut strips, pull the strips off the pack in a Z pattern and you will match color and grain making your joint virtually invisible.
Overlap the two Strips giving yourself enough room to make a diagonal cut