Abstract: A riser tensioning device that utilizes parallel air cans. A stem having an inner diameter larger than the outer diameter of the riser is positioned around the riser and is fastened in position at the wellhead of the riser on the offshore structure. A yoke attached to the stem supports a number of sleeves around the stem. Each sleeve receives a variable buoyancy air can. The sleeves and air cans are provided with a retainer that retains the air cans in the sleeves and transfers the vertical loads of the air cans to the sleeve. The retainer is also designed to allow the air cans to be selectively removed from their individual sleeves without the need to pull the entire riser assembly.