Which trolling motor should you put on a fishing kayak?

No. Federal capacity plate rules under 33 CFR 183 cover monohull boats under 20 feet that are propelled by machinery, and canoes and kayaks are explicitly not covered by that requirement. A kayak's stated maximum capacity is the manufacturer's own figure, not a federally regulated one, and different manufacturers do not always measure or define it the same way. Treat it as a useful reference point rather than a certified rating.

A small 12 volt kayak motor typically weighs 10 to 15 lb, and a single 12 volt deep cycle battery adds another 20 to 35 lb depending on chemistry and capacity, so budget 30 to 50 lb combined before adding the mount hardware. That is a meaningful chunk of most kayaks' rated capacity, which is why weighing the whole setup against 70 percent of the stated maximum matters more on a kayak than it does on a boat with far more capacity to spare.

A bow mount gives straighter tracking and, on the Kayak Terrova, genuine GPS Spot-Lock anchoring, but needs a longer shaft and a bow rigged to accept a bracket. A transom mount is simpler to add to a kayak with no existing bow rigging, costs less, and uses a shorter shaft because a scupper sits closer to the waterline than a bow deck. Most anglers converting an existing paddle kayak start with a transom mount for exactly that reason.

Yes, and it is often the better choice on a kayak specifically because of weight: a lithium battery delivers close to its full rated capacity even at the higher currents a motor draws, where a lead acid battery of the same amp hour rating delivers noticeably less. The battery still needs a charger with a genuine lithium charge profile rather than a lead acid charger, since a lead acid profile will not fill a lithium pack correctly.

A kayak bow sits higher above the waterline than a scupper-mounted transom does on most hulls, so the same shaft length formula, measuring down to the water and adding 16 or 20 inches, produces a longer answer at the bow. That is why the dedicated Kayak Terrova bow motor runs a 36 inch shaft while Newport's kayak transom motors commonly run 24 inches, even though both are built for similar sized kayaks.

It depends on how you fish. GPS Spot-Lock anchoring holds position hands free over structure or a school of fish, which is genuinely valuable for anyone sight fishing or working a specific spot repeatedly. A paddler who mainly wants help covering distance between spots, without needing to hold a precise position, gets most of the practical benefit from a much cheaper transom motor without paying for GPS electronics that go unused.