Can kids under 13 wear them legally. My youngest son is 12 and we do a lot of trolling. The neoprene vest are hot to wear at idle speeds. From what I�ve read I�m not sure. One says it must be a type 1,2 or 3 and the other just says a coastguard approved wearable PFD.

All children under 13 years of age in all vessels under 26 feet in length must
wear a U.S. Coast Guard approved wearable PFD while underway. Underway
means not at anchor, made fast to the shore, or aground.

Vessels 16 feet and longer, excluding canoes and kayaks, are required to be
equipped with one Type IV throwable PFD in addition to the Type I, II, III, or V
PFD required for each person on board.
Inflatable PFDs are authorized only when used in accordance with requirements
as presented on U.S. Coast Guard approval labels.

From the coast Guard:

TYPE V PFDS / SPECIAL USE DEVICES: Only for special uses or conditions.
See label for limits of use:

Hybrid Inflatable PFDs
Canoe/Kayak Vest
Boardsailing Vests
Deck Suits
Work Vests for Commercial Vessels
Commercial Whitewater Vests
Man-Overboard Rescue Devices
Law Enforcement Flotation Devices
Note: The Coast Guard is working with the PFD community to revise the classification and labeling of PFDs. When completed, this information will be updated and hopefully be somewhat easier to understand. Meanwhile, spending a few minutes to understand the many options available to find a PFD that you�re willing to wear could mean the difference between life and death for you or a loved one.

I read this as well but when you look at the water safety act it states only a 1,2 or 3.
Most type 5 say 16 or older and 80 or more pounds. My son is well over 80 pounds and tall for a 12 year old.

I don't think trolling is considered "underway"

Also, there's plenty of type 2 and 3 inflatables available out there

If the boat is moving it is considered underway.

You will have to look at different brands and models of inflatable life vests, and find one that the Coast Guard label says is approved for your 12 year old, by weight or age.

The word "underway" means that a vessel is not at anchor, or made fast to the shore, or aground according to the Coast Guard.

Talked with the local game wardens today and was told as long as he met the weight requirements there would be no problem.

I read on the kill switch law post that underway is 6 mph. My trolling motor doesn't go that fast

Different laws.

The kill switch law includes the term underway at "headway speed" which is arguably and I mean arguably 6 mph. Thank god for that little addition that was missing from previous versions.

If you are not at anchor or morned you are under way. If you motor of sale is in use you are making way.