The 550B Is Designed for High Production and Efficiency in Difficult Ground Both Uphill and Downhill Yarding. The T-MAR 550B is a fast, high performance, one piece move swing yarder optimized for use with a mechanical grapple, msp or light motorized carriage.  It features a full interlocking winch with equal speed drum reversing for grapple open and close.  The efficient winch and light weight make it ideal for heavy, hard to access timber in steep country anywhere.  Its 50’ tower and interlocking winch with oversized water cooled brakes make the most of poor deflection and limited options to yard more, faster.