With your goals, spending
money on a better boat in the first place will end up saving you money (and maybe more) in the long run.
We had nice
weather on a Marblehead-Halifax
Race once, roaring down 15' swells at better than 12 knots on a 42'
sloop. More breeze or a different tide might have made them breaking waves. Not something you'd want to deal with in a 28' boat 100 miles off shore en
route to Sable Island. Figuring a generous
hull speed of 6.5 knots for a
Morgan 28, it would take about 15 hours to sail the 100+ miles from New Harbor to Sable Island. Perhaps possible if you could stay on a broad reach all the way, and the
wind didn't die, change direction, or mood. Any of those things happening could ruin your adventure, turning it harrowing, worrisome, or dangerous, depending on the
weather and your skills. As tkeith suggests, seaworthiness depends a lot on the sailor knowing what his or her boat can handle, and how to handle it. A bigger, better boat would make knowing how to handle such a trip easier. If I made such a trip on my boat, my
liferaft would be on board.