It would be an interesting experiment.
I would not expect the boat to last more than a season or two.
I would not take it very far from shore, ie how far can you swim?

In addition to the other things written here about OSB I'd also consider:
- how resistant would the spray on truck bed liner be to scrapes? If the
chips get wet they will swell. I'd put a pair of skids on the bottom to
protect the hull from scrapes in hopes the boat would last longer.
- once the chips in the board get wet and start to swell like the stuff
you see left uncovered in sheds and other buidlings, I imagine it would be
very difficult to make watertight again, ie hard to repair and keep
watertight once it starts to go.
- there's so much glue in OSB the boat will be heavier than plywood.
I'd take a pair of bathroom scales to the lumber yard and weight a sheet,
then calculate the weight of the boat before building it.

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