Joint owner of "Reefer" which is a Robber 3E version with taller rig and different shroud positions.
The Robber is a safe boat to sail in a blow and can subject to flat water outpace many larger boats upwind. However, in the light they tend to stick badly and careful attention to trim is crucial to keeping the boat moving. To combat this we added 1m to the mainsail hoist and approx 10 inches to the boom length. Whilst the rating is correspondingly high, the extra performance is certainly welcome, although I have been advised by a more experienced Robber owner that the best solution is to decrease the foresail area by moving the mast forward 18 inches, whilst at the same time increasing the mast height which gives you a much more powerful mainsail. Certainly this worked for Throbber, which is probably the fastest MK1 around. Movement of the mast post then becomes an issue with the MK 3 version, as you will have to support the base of the mast post.
A few years ago, survey report identified that the keel to hull joint was typical of the build era (i.e. simple GRP recess to receive bolted keel flange) and by today’s standards would be considered a little light. We added 5No.75mm ply stingers across the keel area, which undoubtedly helps stiffen the bottom of the boat. Whilst this work was probably unnecessary, we do have increased faith in the boat withstanding a bad grounding.