Do you fish out of a SOT (sit-on-top) kayak, or have you tried fishing from this platform?
If so, you may have wondered why it is sluggish and hard to paddle, and why water coming out of the scupper holes keeps flooding your ride’s deck. In fact, you may have even decided to plug those scupper holes once and for all, as many SOT kayak anglers do, eventually.
Part of the SOT kayak’s sluggishness is the result of its being typically wider than other types of kayak (e.g. sit-in and W kayak) in order to compensate for its inferior stability, which is the result of the user being seated in the L-position on top of an elevated deck.
But there’s more to it, and this article discussing the hull design of SOT kayaks explains the negative effects that scupper holes and narrow tunnels incorporated into the hull have on the kayak’s hydrodynamics, namely how they work to reduce its speed.
It turns out that both scupper holes and narrow channels or tunnels create turbulence and drag that make the SOT kayak’s hull even less efficient in hydrodynamic terms.
Most interesting is the revelation that scupper holes are there not to drain water from the kayak’s deck, but these vertical molded-in tunnels’ main job is to prevent the deck from collapsing under the weight of the user and their gear.