3 ms·

So many things are obvious once pointed out. I never would have thought of pressure gradients but once you did it's obviously a very uneven surface and you don

So many things are obvious once pointed out. I never would have thought of pressure gradients but once you did it's obviously a very uneven surface and you don't do that in anything contending with a lot of drag. How do you see this as a SWATH? This is a catamaran that combines buoyancy and propulsion. I do agree it has a high center of gravity, but that's a relative term--what counts is the ratio of height to width. And a catamaran or SWATH has a much wider base than a typical ship. Wikipedia says SWATH ships require complex control systems--why? Yes, they're very load sensitive because the small contact at the surface means a lot of vertical movement to compensate for weight changes, but couldn't that simply be handled with some pumps and tanks? Make the ship always weigh X--take on water or pump it out as needed to maintain that X.

usrusr 3y ago
I'm not a marine anything, but I'd assume that the control system Wikipedia mentions are ballast tanks that need to reflect any change in load, load distribution and even wind load I'd guess. Sinking a little deeper won't do much to compensate increased load because the small surface area means little change in displacement per change in vertical position. Active trimming pumps.
- LorenPechtel 3y ago
  Yes, but how is that all that complex by modern standards? Dealing with known weight, simply pump the right number of gallons. If your ship can change weight rapidly you might need some fairly big pumps. (I'm thinking of a warship--VLS equipped ships can throw an awful lot of weight into the sky awfully quickly. But on the flip side you can dispense with a whole bunch of stuff meant to deal with the missile exhaust--your VLS tubes go all the way through the ship, when the missile lights it simply blows a panel open on the bottom of the cell and the exhaust slams into the ocean. And it's a safety advantage to be able to jettison a missile without having to launch it or rig a crane.)
  - usrusr 3y ago
    More complex than a hull shape that is perfectly fine with just sinking in in a little deeper when load is added or redistributed. The control system you don't have or need is inherently less complex than the control system you do need. It's not exactly a problem impossible to solve, SWATH have already been operated half a century ago, but it seems to be rarely worth the effort.

usrusr 3y ago

I'm not a marine anything, but I'd assume that the control system Wikipedia mentions are ballast tanks that need to reflect any change in load, load distribution and even wind load I'd guess. Sinking a little deeper won't do much to compensate increased load because the small surface area means little change in displacement per change in vertical position. Active trimming pumps.

LorenPechtel 3y ago
Yes, but how is that all that complex by modern standards? Dealing with known weight, simply pump the right number of gallons. If your ship can change weight rapidly you might need some fairly big pumps. (I'm thinking of a warship--VLS equipped ships can throw an awful lot of weight into the sky awfully quickly. But on the flip side you can dispense with a whole bunch of stuff meant to deal with the missile exhaust--your VLS tubes go all the way through the ship, when the missile lights it simply blows a panel open on the bottom of the cell and the exhaust slams into the ocean. And it's a safety advantage to be able to jettison a missile without having to launch it or rig a crane.)
- usrusr 3y ago
  More complex than a hull shape that is perfectly fine with just sinking in in a little deeper when load is added or redistributed. The control system you don't have or need is inherently less complex than the control system you do need. It's not exactly a problem impossible to solve, SWATH have already been operated half a century ago, but it seems to be rarely worth the effort.