Is that a hard shell kayak or a diy skin on frame kayak? The SoF kayaks are even quieter.
With SoF kayaks your legs feel every little wavelet hit the side of the boat. The flex of the skin dampens out the sound that would be heard on a hard shell boat. I don't have home made ones, just the commercially made folding kayak types. I was kayaking on the outer banks of N.C. a few years ago. In the fall just after the summer when several shark attacks were reported along the east coast down into Fla. One of which had occurred not far from the same area of N.C. I was kayaking.
Twice during that vacation while kayaking in the sound I noticed a silver flash just below the surface followed quickly by a hard thumb on the skin of the kayak. Scares the crap out of you for an instant following the stories from earlier in the year. Kayaks are attacked by sharks ever now an again. In my particular experience I suppose it was just blue fish or some similar species being chased and hitting the boat. Goes to show just how quiet SoF kayaks are. The Greenlanders and Inuit used them for a reason.
You're not at the top of the food chain in salt water. However - It's best not to think about such things to much. Else your imagination summons up images like these:


This one is the result of one real attack, note the kayaker was not harmed.

I've never tried tenkara fishing from any of my kayaks. Just hand line fishing: a spool, some line and some lures to tow. I took my son and a friend to a local lake last summer, they went out in a Pakboat canoe looking for that pool of bass. I took my FC Java , but never put it together to get on the water. I was catching plenty of fish from the shore. OK mostly blue gill and ever once in a while a far sized bass. Plenty of bass in that particular lake because all bass must be returned. Other fish can be kept if you want.
Maybe next summer I will give kayak/tenkara fishing a try.
btw - here's a link if you'd like to read the scariest kayak shark attack story I've ever read. It wasn't a quick hit and then over. It dragged out for 20 minutes or so of stalking. Must have felt like hours to the kayak fisherman in NZ. This poor guy really did get the crap scared out of him.
http://www.fishingkites.co.nz/sharks/gr ... ttack.html 