If the seller misrepresented (lied about) the condition the boat was in to get you to agree to the trade, AND it was reasonable for you to rely on that misrepresentation (that is, for example, you did not have the chance to inspect the boat before  the trade; or if you did, the problems were  not ones you could have found on such inspection), then he may have committed fraud. Fraud can provide a basis to seek monetary compensation and/or rescind the sale (return boat, get bike back). Note that if he will not voluntary compensate you or rescind, you'd have to sue him to enforce your rights, which may or may not be economically worthwhile doing.