I have read several other threads discussing the 'what ifs' regarding the accidental loss of a weight belt, and now have first hand experience. My buddy (who is also my nephew) and I were enjoying a 2x4 'wreck' at 60 feet in Tobermory last weekend, pacing ourselves for a leisurely dive. We had circled the wreck once and were in the process of doing another loop when I had noticed a slight cloud of silt appear at the edge of my peripheral vision. I quickly realized that it was my buddy's weight belt (colorful weights) and instinctively reached for him (we stay within 3' of each other usually) and managed to snag his fin. Securing a better hold on his ankle (I think) I swam down as fast as I could, but I ended up doing a few 360s thanks to his buoyancy. Considering that the belt had 24 pounds of lead, it was no surprise that we were ascending at an alarming rate. While he had dumped most of his air initially he did not continuously do so, adding to our ascent. I usually take ascents slow as my ears and sinuses sometimes give me a few problems but strangely they managed to equalize even during our more rapid phase. When we broke the surface (could have been in as little as 10-15 seconds, could have been more) I think we both took a few seconds to run internal systems checks (lungs...present, sensation in all limbs...check) before simultaneously asking each other if we're okay. We both indicated that we were and managed a few chuckles over what could have been a serious event. We spent a great deal of time discussing the dive, noting that we (I) did a poor job examining his equipment before the dive (he has virtually no hips so the weight belt was held up by tension alone and hence it becoming loose when the 14mm of neoprene compressed at depth), and also that he should have assumed a horizontal position during the ascent. Not -completely- emptying the BC was also a big problem, probably a fatal one if I wasn't able to grab him. This was a learning experience for us neophyte divers!