Go here for Print Friendly Page



Why are small boats required to have flotation, and why are there different requirements.?

Back in the 50's and 60's the old Boating Industry Association (now NMMA) and the Yacht Safety Bureau (now ABYC) realized that one of the main reasons people died in boat accidents was the boat sank out from under them. Sounds obvious but it wasn't really.  Then in the 1970's a lot of research was done into hypothermia, and the two came together. It was realized that if the boat did not sink, it would give the people something to hang onto, that could be seen much better than just a head sticking out of the water, and if the boat, although full of water, did not sink, or roll over, then the people could actually stay in the boat. Most of their torso would be out of the water reducing the effects of hypothermia, and providing a much better rescue platform.

So work started on developing a standard for flotation.  Through testing and experiments techniques were developed that would provide enough flotation to keep a small boat afloat, and floating relatively level. However, this did not work well for inboard boats, because the size and weight of the engines required far too much flotation material to float the boat level.

Meanwhile the Federal Boat Safety Act passed in 1971 and went into effect in 1972. The Coast Guard began collecting statistical data on boating accidents.  Analysis of this data revealed that the most significant contributors to fatalities were capsize, sinking and falls overboard. Flotation in a boat could eliminate the sinking, prevent capsizing, and prevent some of the falls overboard.  Many of the "falls overboard" were actually the boat rolling over and dumping everyone in the drink. Also analysis revealed that by far the majority of these accidents occurred in monohulled boats under 20 feet in length, manually propelled or with outboard power. The inboards contributed some.

Content Continues After Ad

So between NMMA, ABYC, and the Coast Guard it was determined that monohull boats under 20 feet with outboard power or manually propelled should have level flotation, and inboard boats basic flotation.  Basic flotation simply keeps the boat afloat with some of the boat sticking out of the water.

When the regulation was proposed many people in the classic and wooden boat community felt that the standard was too rigid to be applicable to small manually propelled boats or boats with tiny engines.  So after testing and consultation with persons building these types of boats the standard was modified to allow some latitude in achieving the same performance.  That is, these boats have to float level to the same degree as larger boats with bigger outboards, but the method of achieving it is different. It was called modified level flotation. Additionally this small boats are allowed to carry a greater percentage of their weight capacity as persons, than larger boats are. This seemed to satisfy everyone.

This particular standard has been a rousing success in preventing deaths.  It is not clear and probably not quantifiable just how many deaths have been prevented but the fatalities have dropped dramatically since 1972, from about 19 per 100,000 boat, or about 1300 people, to less than 6 per 100,000 boats, about 600, annually in 2005.  At the same time the boating population has grown to roughly 5 times what is was then. The drop in fatalities is a combined result of education, engineering and enforcement, so it is hard to say which has contributed more, but certainly flotation standards have had an effect.

© 2007 All Rights Reserved. Revised 01/28/2018


American Boat And Yacht Council  Boat Design Net  Wooden Boat Foundation

This Web site may contain copyrighted material the use of which has not always been specifically authorized by the copyright owner. I am making such material available in my efforts to advance understanding of educational, economic, and scientific issues, etc. I believe this constitutes a "fair use" of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this Web site is distributed without profit to those who have expressed a prior interest in receiving the included information for nonprofit educational purposes. For more information see: If you wish to use copyrighted material from this Web site for purposes of your own that go beyond "fair use", you must obtain permission from the copyright owner.

Created with Dreamweaver 21.2 © 2022 All Rights Reserved