Prospectus excerpt:  We are offering 6,000,000 of our 8.50% Series B Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units, liquidation preference $25.00 per unit (or the Series B Preferred Units). Distributions on the Series B Preferred Units are cumulative from the date of original issue and will be payable quarterly in arrears on the 15th day of January, April, July and October of each year, when, as and if declared by the board of directors of our general partner. The initial distribution on the Series B Preferred Units offered hereby will be payable on January 15, 2018 in an amount equal to $0.40139 per unit. Distributions will be payable out of amounts legally available for distributions (i) from and including the original issue date to, but excluding October 15, 2027 at a fixed rate equal to 8.50% per annum of the stated liquidation preference and (ii) from and including October 15, 2027, at a floating rate equal to three-month LIBOR plus a spread of 624.1 basis points.