Why are VPM Decompression Tables so Similar to the RGBM Tables?
Why have VPM tables always been so similar to Bruce Wienke’s RGBM tables? Until 2002, this was simply because the RGBM was essentially the same as the VPM for a single decompression dive. Even though Wienke claims to have “abandoned” VPM, his publications and publicity from vendor partners belie this as marketing over substance. Wienke apparently still uses core elements of Yount and Hoffman’s VPM algorithm as a basis for the RGBM. Even today, in 2004, it can be demonstrated from commercial programs that the “full-up” RGBM is still underpinned by Yount and Hoffman’s iterative algorithm. With the wide distribution of open source VPM, Wienke was placed under pressure to differentiate his product by customers who had paid for material that could be obtained virtually for free. Since 2002, this has resulted in a new RGBM model, publicized in dive industry print and venues. Nonetheless, as demonstrated by the close correlation of ascent data for VPM and RGBM, this work has actually only res
