To all interested parties.... Last evening, I received notification that there is a new flavor of AIS that will be interesting to pleasure craft owners/operators. Those of you who know me know I am not a fan of Class B AIS for pleasure craft. (I will remind you that I see Class B AIS as appropriate ONLY in 5 situations: 1) reduced visibility, 2) night operations, 3) offshore operations, 4) the inland rivers, and 5) boat not-under-command). While many disagree with me, my assessment and conclusion is informed by Class B technology limitations that I believe create a false sense of security in many - if not the majority - of pleasure craft operators. Review my article on this on my website for the whole story. Here is a link to that article: https://gilwellbear.wordpress.com/category/boat-technical-topics/equipment-topics/ais/. Well, apparently the world-wide "powers that be" (International Marine Organization, USCG) agree with me, and there is now a new AIS communications standard called "Class B+." Note the "+" sign in "B+." Here are the differences introduced by the new standard as I understand them today: 1. Class B unit radios are 2 Watts, Class B+ radios are 5 Watts; creates additional range. 2. Class B transmit interval is 30 seconds; Class B+ interval is 30 seconds up to 14 kts, then 15 seconds up to 23 kts, then 5 seconds above 23 kts. This will greatly enhance position accuracy for go-fast boats. 3, But by far the most important safety improvement is that the new Class B+ standard uses SOTDMA rather than CSTDMA to decide when to transmit. The CSTDMA technology DOES NOT ensure that a message will be sent in the clear; it's entirely possible for CSTDMA messages to be lost without the vessel operator knowing that. This obviously creates unreliable position accuracy and a false sense of security. The SOTDMA technology (which is used by Class A AIS) guarantees a time slot on the AIS VHF Data Link for clear message transmission. That is very important in crowded areas, like Mobile Harbor, Charleston Harbor, Norfolk Harbor or in areas with very heavy pleasure craft traffic, like Annapolis. Today as far as I know, Sitex and Digital Yacht have Class B+ products available for sale. If you do not have AIS today, and might be considering adding AIS to your boat, I strongly recommend you consider these new Class B+ products in place of the existing Class B products. Class B+ is still not as good as Class A, but they are a very significant improvement over what we have today. Jim Peg and Jim Healy aboard Sanctuary, currently at Charlotte Harbor, Punta Gorda, FL http://gilwellbear.wordpress.com Monk 36 Hull #132 MMSI #367042570 AGLCA #3767 MTOA #3436