Fraud is the intentional misrepresentation of a material fact made with knowledge of its falsity and with the intent to induce your reliance upon which you jusitiably relied to your detriment.In other words, your mother would not have purchased the kayaks had she known their true condition, that they leaked.In a lawsuit for fraud, your mother's damages (monetary compensation) would be a refund of the amount she paid for the kayaks.  She can alos seek punitive damages which are a substantial additional amount to punish the intentional, malicious, wrongful act of the seller of the kayaks.