Everything Totally Explained


Ask & we'll explain, totally!
Pontoon effect
Totally Explained


  FOR SALE!Either this or the left-hand panel are available for just $19.95 per
day, or you can have both for only $34.95! Contact us for details.  


View this entry using RSS

Everything about The Pontoon Effect totally explained

The pontoon effect refers to the tendency of a vessel whose flotation depends on lateral pontoons to capsize without warning when a lateral force is applied. The effect can be sudden and dramatic because the vessel is stable and self-righting as greater lateral force is applied, up to the point that the pontoon(s) on one side of the vessel are completely submerged. At this point, stability suddenly disappears and the vessel rapidly capsizes.
   (The same term can also arise when describing a design in which the attributes of a pontoon are created without using explicit pontoons--when a design effectively incorporates pontoons. This page describes the specific phenomenon described above.)
   The pontoon effect is theoretically possible whenever the vessel's entire weight exceeds the buoyancy of the pontoon(s) on either side. However, the pontoon effect is much more likely in vessels with a high center of gravity and low or non-existent displacement other than the pontoons.
   A pontoon vessel such as a catamaran floats in a level position when the center of gravity of the entire vessel (including its load) is above the center of buoyancy. If it tips, the vessel will be stable as long as the center of gravity doesn't move further to the side than the center of buoyancy. Under these conditions a "righting force" (a turning moment) acts on the vessel to push it back toward the level position.
   However if the center of gravity is high relative to the width of the vessel, and the pontoons on one side are unable to bear the vessel's complete weight, the lateral movement of the center of buoyancy will be restricted. Even a relatively small lateral force can move the center of gravity further to the side than the center of buoyancy can go. At this point, the righting force will disappear, replaced by a turning moment in the opposite direction. This can capsize the vessel at the point at which one pontoon is completely submerged.
   When using twin lateral pontoons, each pontoon should have enough buoyancy to bear the load of the entire vessel on its own. If the vessel is so heavy that either pontoon is mostly submerged when no lateral force is applied, it'll be vulnerable to the pontoon effect. If sufficient lateral force arises (such as wind or shifting load), the vessel can tip enough to submerge one pontoon. At this point, the sunken pontoon will provide no further buoyancy to right the vessel. As the center of buoyancy can't move further to that side to match the center of gravity, that pontoon will continue sinking. The tipping angle will increase until the vessel capsizes. This can continue until the vessel inverts completely with the pontoons again floating on the surface but the rest of the vessel underwater. At this point, the upside-down vessel will be highly stable. If, on the other hand, the vessel is design and loaded so that each pontoon can support the vessel's entire weight, the center of gravity can't move transversely beyond the center of buoyancy at the most extreme tipping angle, and the pontoon effect can't occur.
   In the abstract sense, the principles at work govern the stability of all boats and ships including those without lateral pontoons. See angle of loll and metacentric height.

Further Information

Get more info on 'Pontoon Effect'.


External Link Exchanges

Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:

    <a href="http://pontoon_effect.totallyexplained.com">Pontoon effect Totally Explained</a>

Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
   As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned.



Copyright © 2007-8 totallyexplained.com | Licensed under the GNU Free Documentation License | Site Map
This article contains text from the Wikipedia article Pontoon effect (History) and is released under the GFDL | RSS Version