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Helm Seat, Sierra Boat Seat, Torsion 380 Mechanical Suspension

Mfr. H.O. Bostrom

Helm Seat, Sierra Boat Seat, Torsion 380 Mechanical Suspension

Sierra SeaPost Torsion Helm Seat with H.O. Bostrom's Torsion 380 Mechanical Suspension is a custom built marine seat with 4" of suspension travel providing operator comfort on any boat and comes with a 5 year warranty.

  • 6" of horizontal fore/aft adjustment
  • Easy-turn dial adjusts suspension for operators weighing 110 lbs/50 kg to 275 lbs/125 kg
  • High or low back heights available
    • High and low back styles available with arm rests
    • High back comes standard with knob adjustable lumbar support and reclining back (25° from vertical)
  • Suspension base cover included
Options available at additional costs include: four-way height adjustment with 2.4"/60 mm of vertical travel, two point seat-belt, hip restraints, and flip-up armrests that lock in three positions.

These helm seats are made to order and typically take between 2-4 weeks. Please contact us if you have any questions.

Note: H.O. Bostrom seats do not ship USPS.

$855.41 - $963.88

Additional Description

  • Helm seats are fully "marinized" with two-coat metal finish. A phosphate base coat, plus a baked TGIC polyester powder paint finish allows the finish to survive 1,000 hours of salt spray testing. All hardware is non-corrosive.
  • Your choice of upholstery: We offer two fabric colors and four vinyl colors. Custom materials are also available.
  • Lumbar Support is adjustable or built-in depending on model.
  • Durable armrests are fully adjustable and withstand up to 400 pounds. Arm ends allow you to mount controls.
  • Sleek, quick-change upholstery kit on new product line lets you replace worn upholstery without removing the seat assembly.
  • Combine components to meet your special needs; i.e., the pedestal and swivel assembly on the high-back helm seat can also be used on the floor slide rail. Or vary the seat back height, from low to high.
  • Serpentine seat springs isolate shock from rough seas.
  • High density seat cushion and padding are contour molded for added comfort.

The Sierra Torsion 380 combines heavy duty, mechanical suspension with an ergonomic upper seat to provide you with the ultimate in driver comfort. The unique, low profile, torsion bar suspension provides 4 inches of shock absorbing ride. The weight adjustment allows the same level ride regardless of the operator's weight with adjustment from 110 to 275 pounds. The Torsion 380 can be combined with a 3 inch height adjust for optimal flexibility or with a static riser when a higher profile option is needed. High or low back available with optional back recline and armrest.

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Accessories, Related Items, Spare Parts, ...

SeaPost Seat Riser, 7.25"

SeaPost Seat Riser, 7.25"

Mfr. H.O. Bostrom | Mfr No. 3328-296

Used with above Part#: 100046, 100049, 100052, 100055, 100058, 100061, 96885, 96891
Not Currently Available

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Review and FAQ Center


Does the seapost Siera seat with torsion 380 swivel 180 degrees?

Submitted by: Reid

No, the Sierra helm seat you are referring to does not swivel. Below are some links to our website to seats that do swivel:

SeaPost Console Marine Helm Seat

Mariner - Boat Seat, Bentley's Marine Seating


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