The Suspenz Smart Airless DLX Cart is really good. It has a thick coat of paint which protects from scratches and rust in salt water environments, the wheels are airless, so there is no risk of puncture or need be be inflated from time to time.
The padding on the saddle protects the kayak hull from scratches, and the straps also have a lip of fabric for protection from scratches against the kayak. The one big disadvantage I have found with this cart is that it is too bulky to take with you in an expedition as it will take up most of the space in the stern hatch. If there was a way to break down the main frame into two or more pieces then it would be perfect, but as it is, you can really only use it for day trips.
The Youtube Video from Explore tech Adventure does a decent job of explaining the features of the Suspenz cart, however, they do have an open top kayak. In fact, nearly everyone who reviews this kayak has an open top. so for a sit inside kayak, you need something more compact that takes as little space as possible.
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