Hi my old man is thinking of buying a pedalfish 13 or 10, but is unsure which would best suit offshore fishing
Cheers Anthony

Honestly, neither! If you had to then 13 foot but if he wants offshore without a paddle, buy a hobie adventure island.

Out of the Hobie range an Adventure or a Revolution 13/16 both suit a wide range of offshore conditions. The Adventure island is obviously more capable but costs a lot more for that extra capability. A wide range of other kayaks can be used offshore but will have a narrower range of conditions and not best suited to less experienced paddlers. (I've used a PA a lot offshore but I wouldn't class this as an offshore yak -especially the newer models, and not for those without a lot of offshore experience). The pedalfish and native (imo) have hull designs and especially the high centre of gravity's that are generally not well suited for offshore use. You should be looking for longer kayak that can cut through waves and chop and provide good stability in very rough conditions. Generally the pick in this area are the models first mentioned, glass skis or longer/sleeker paddle yaks like the longer oceans kayaks or vikings.