Cheers It ended up being about just less than 100mm wider than it was previously, judging by where the rollers sit (I didn't measure it previously). There are no beam supports on the trailer (which id love to add), and the hulls sit on some narrow rollers which the roller supports are welded to the trailer, so I need to move these both outwards. I'll probably end up grinding the welds out and bolting the roller supports into the new positions.