That grooved bow section doesn't work as well as you might think; once the rubber is cut the sides are not particularly supportive and the bow line can easily distort the rubber and roll out. What I've found does work is to cut the groove and fit a rope from the outside bow fastening, over the bow to an inside fastening keeping it fairly taught. When making up this rope, tie an 'eye' in it with a stainless ferrule inside, position it just over the top of the bow. You can tie off to this for an anchor, a mooring warp, a temporary rope to the trailer when launching etc. I've also found a good method of mooring is to tether the warp inside the front bow but run it through the eye as a guide. The benefits to use and the boat are: easy access to the tie off point for you from within the boat, similarly from outside the boat, it prevents chafing of the tubes and removes the guide problem over the bow when anchoring. I might add that I also have a section of flat strake from the D section down the tube into the boat to prevent any fretting that could occur. It shows no sign of this though even after many years of use.
It does leave the eye protruding a wee bit when not in use and I know many of the ribnetters are bling merchants first so it may offend their sensitivity. I don't have this emotional problem.