Gel coat resin cannot be used to deep fill in voids in the laminate structure. You should fill the voids with resin mixed with a filler. Then top coat the repair with gel coat resin. Gel coat resin is brittle and will be easily cracked again if you just put globs of gel coat into a void. I prefer epoxy resin for repairs because epoxy resin is a stronger bonding agent than laminating resin (polyester resin). If you use epoxy resin you must thoroughly wash the cured resin to remove amine blush on the surface. Amine blush will inhibit the curing of gel coat resin if it is left on the surface of a repair. Gel coat resin will not cure to a hard surface unless the surface is prevented from exposure to air, so gel coat patch resin contains a wax. Or poly-vinyl alcohol can be used to cover the gel coat while curing.
Read more about repairs in the FAQ at
Q5: how is damage to a Unibond hull repaired?
https://continuouswave.com/whaler/reference/FAQ/#Q5Read all the recommended articles linked from the FAQ.
Also, the damage probably was caused from hitting a dock. They could also have been some forward motion on the boat when it hit the dock, the damages seem to be in a line, as if the boat was moving forward somewhat at the time of impact. I would not call the damage just cosmetic because it exposed the underlying laminate layers and creates an opening in the hull where water could enter. Cosmetic damage would he damage that was limited to just a scratch into the surface of the gel coat layer. This damage has clearly broken away the entire gel coat layer and exposed the laminate layers.
There may have been some voids in the hull in the original manufacture, and that is why there appears to be an air gap between the gel coat layer and the laminate, or the gel coat layer has moved away from the laminate after the impact. The gel coat layer should be strongly bonded to the underlying laminate layers, and that bond does NOT seem to appear in the close-up images.
These areas appear to be in a high-visibility part of the boat, so you will want to make the repairs blend into the hull as much as possible. Using the Spectrum gel coat patch kit resin should give you a good color match. If you are not skilled in using resins to make repairs, you should first attempt a repair to a not-so-visible area of damage.
The damage shown in Figure 3 looks rather deep, but it may be just the photograph is a very extreme close-up view. In that image the gel coat looks like it did not have a good primary bond to the underlying laminate layers. The laminate layer looks very dry.