"Boatanchors"
I don’t really like the term "Boatanchors". I assume it comes from across the pond, where the military had so much kit that they could afford to chuck 100lbs of high grade communications gear over the side to keep an MTB from drifting onto the beach! Personally, I think a more British term is called for. Something like "Barndoorstops" or maybe just "Backbreakers". Please feel free to email your suggestions!
More to follow soon - watch this space!