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Wave Grenade RDM Aluminium Extension


(6 customer reviews)

The Severne wave grenade mast extension in reduced diameter has been developed to specifically enhance the performance, lightweight and ease of use of the Severne rig. All Severne Extensions have a slimline stainless steel automatic hinged collar system, for increased reliability and ease of rigging.

All Severne Extensions have a precision milled stainless steel button and mechanism for reliability.

Product Description

A no compromise RDM extension designed for durability and function. This RDM extension has a 0cm setting, making it the lowest in the industry.

Durability and Function

  • Stainless steel automatic hinged collar system
  • Stainless steel button and mechanism for improved reliability
  • 0cm setting for increased functional range
  • Internal metal chassis for durability
  • Unique Severne geometry pulley alignment for efficient down-hauling

Additional Information


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6 reviews for Wave Grenade RDM Aluminium Extension

  1. Neil Greentree

    What’s important to know about all Severne mast extensions is that they are engineered to match the sail’s pulleys so down hauling is easier. So much easier that I rigged my cammed Overdrive sails without using a rigging winch!

  2. Jonny Gambell

    I have just got my Severne 36cm Aluminium extension and it is great. If you use Severne sails i would definitely recommend these extensions because of the ease of rigging. The pulleys line up perfectly with no crossing in the rope and the collar is very well engineered for super easy use! RECOMMENDED!

  3. Steve Chatten (Team Rider)

    As with all of the Severne range extensions, they are designed for function and reliability.

    Race extension HD SDM
    Made of a solid aluminium tube combined with a triple pulley system that’s friction free for easy down-hauling. The pulley system is aligned with the system on the Severne sails so it’s hassel free. The other fittings used are made of stainless steel for improved reliability.
    Available in three sizes –
    16cm for the racing and speed sailor that wants to shave off weight by only using a small extension.
    Use the 24cm for your mid range kit and 36cm for extra length when needed.
    I used them on the BSA with Overdrive’s and didn’t need a downhaul pulley.

    For more information or help please call

  4. Penny Wiles (verified owner)

    It’s a dream. I have now used my carbon wave grenade extension twice. It’s unbelievably easy to downhaul, no more rig winching, the pulleys line up with the sails pulleys perfectly. Great buy.

  5. Jonny Utah

    This is one tough piece of kit.Because im light I use a 370 mast with my 4.7 so my extension needs to be really strong when being used in the 36cm position.I also agree with the other guys that its sooooo easy to downhaul.

  6. Tom McClelland

    Just like the deckplate, this is a very well thought out ergonomic design. I really can’t fault it in any way. Lots of little touches that show that the designers were thinking about how to make rigging and de-rigging as easy as possible.

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