NRS River Cat and Kodiak cataraft tubes use a proprietary two-piece plastic nose cone to seal the ends of the tubes. We use top-quality "50-year" silicone sealant to bond the nose cone to the boat material. If you experience air leaking around a nose cone it usually results from one of two things. Either the silicone has been dislodged or the inner part of the cone has cracked, usually from a crash against a rock or other hard object. This video shows you how to repair a nose cone leak.