...If we're wrong, then at least we it's not the first time assumed something wrongly...but I seriously doubt that ammonites with large and heavy shells that are upright would most certinaly topple, no?
'Ammoniten konnten ganz sicher nicht schwimmen. Das lässt sich mit den von Archimedes schon vor 2000 Jahren gefundenen Regeln der Hydrostatik sowie der Hebelge- setze ganz eindeutig nachweisen. Sie waren ausnahmslos Bodenbewohner und mussten sich somit kriechend fort- bewegen, auch wenn es mancher Thomas nicht so recht glauben mag - not my problem.'
'Ammonites were certainly unable to swim. This is proven, without a doubt, by the rules of hydrostatics (discovered by Archimedes more than 2000 years ago), as well as the principle of the lever (?). They were, without exception, benthic ('floor-residents') and therefore moved by crawling; if some people choose not to believe this, not my problem.'
Some very persuasive arguments (no x+y stuff to confuse me) are brought up on the hydrostatics page. One question though, Spirula is used as an example for vertical shell (or body) orientation, why is it not crawling along the bottom like a snail?
Should I really question my belief in Santa Claus?
I must say everybody is entitled to their own opinion, but i strongly disagree with this German guy Eble. He is by the way a physicist and not a paleontologist, who also claims that archaeopteryx was a underwater swimmer. He states that all ammonoids (heteromorph or not) were benthonic (and by this he mains really benthonic on the bottom and not demersal like some fish). He came to this by making false assumptions on ammonoid growth and his own calculations of negative buoyancy of ammonoids, which were proven wrong by all other studies, which all gave values within the margin of error of neutral buoyancy. If would by the way be very hard to live on the seafloor with a negatively buoyant shell (must of been drag carrying that around). It think it is ok to assume that the hydrostatic apparatus was working, because they all (even the weirdest heteromorphs like Nipponites) posses (and did not lose) their siphuncle. So per definition they would be somewhere in the water column from swimmers to planktonic floaters or vertical migrants. Some of them could have feeded demersally on the bottom (some orthoconic forms without adapical ballast) or potentially gyroconic forms, while other must have unmistakenly fed in the water column with a stabile upward pointed aperture (assuming soft parts filled the entire body chambers => see some of the discussions from Neal Monks)...