Plastic (typically polyethylene) surfskis are considerably heavier than their fiber based (fiberglass, carbon, Kevlar) siblings, but they do have a very significant advantage over their lighter counterparts in terms of durability and capacity to absorb collisions and abrasions. If you are anticipating rough care and/or negligent storage habits for a surfski OR you want to use a surfski for rivers or shore breaks where bumps and scrapes are likely, then a plastic surfski might very well be a worthwhile investment. They are less expensive than their fiber construction equivalents. Plastic surfskis can also be handy for rescue drills where you do not want to worry about banging surfskis together. Some plastic surfskis also have flip up rudder options (sea kayak style) that can be quite useful if you will be doing a lot of shallow water paddling.
Many of these models are no longer being manufactured, but due to their durability they can still come up for sale (used) from time to time on used equipment webpages and auction websites. Or if you advertise that you are looking for one, you may spark some owner's recollection of the one sitting in their back yard that they no longer ever paddle. But pay attention to UV damage/sag if the boat has been basking in the sun for a long time. Sag can sometimes be corrected by flipping the boat for a period in the sun. Ultimately these boats should probably be stored sideways?
Epic V7
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Nelo 510
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Epic V5 (at least one of these is rotomolded)
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Spirit PRS 570
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Epic V5 Surfing in Taiwan - with Greenland style paddle
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Pyranha Octane
surfing video (the Octane is the red surfski - this video did not allow embedded window)
Nelo 510
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