I have a Ride 115, with a Lowrance Elite 4 gps/2d BW model for mine, on a RAM mount. Since you have a SINK, you are a bit more limited on mounting options, but its possible. I would mount the transducer to the inside of the hull, possibly under the seat or in one of the storage areas, and use GOOP marine adhesive, make a good size puddle of it and stick the transducer down in it and let it set up. You can remove it/GOOP with a putty knife if needed. Can also use plumbers putty as well, but have not tried it. Google transducer install for kayak, and you'll get some good tips on how to do it, and possibly even for your particular yak. If you do use GOOP, make sure there are NO air bubbles in the goop, as it will cause interference just like air bubbles around the transducer if in water will cause interference.

For power, I use a 12v deer feeder battery, and made a watertight battery box with connectors. Battery will power my FF for 2-3 trips before it needs re-charging. Again, google this and you'll have some good leads on how to do your install.