First things first, find out what kind of material the rc boat is made of. A fibreglass boat will be repaired differently from a plastic or wooden.
To ensure that the hull is repaired properly and is long lasting, then it would be wise to take a bit of time to find our what kind of material the boat is made of, what kind of glues are best, and whether the hull can be self-repaired or if you need to obtain expert help.
If your boat is fibreglass then the best option would be to use an epoxy resin. The resin makes it easy by plugging in the hole with the resin and then sanding the surface after it has dried for a while. After that simply paint over it or varnish it properly.
The good thing about fibreglass is that there is mesh that you can use for bigger holes and cracks. Just plug the holes or cracks with the mesh and apply the resin and allow time for the resin to dry thoroughly before sanding and then painting.
Plastic is different from fibreglass and can be fixed using a modelling glue to stick parts together. Modelling putty can be used for bigger holes.
This boats are not that hard to repair once you have the right material available. For splits in the wood, the job is more difficult as you will need to remove whole pieces and replace these with exact shaped pieces of wood, usually ply. For gluing purposes, different repair shops use slow cure epoxy with slow cure hardner and others also use a wood glue or titebond. Play a visit to your local RC Boat store for more advice on this matter.
Leaks are usually at the rivet joints and would need to be fixed using a rivet repair kit. There are gluing or welding options but the popular one to use would be the riveting option.
A popular option is the 3M 5200 sealant. This can seal leaks for years and is an easy way to fix troublesome leaks. Another way to fix a leak is by using an Aluminium boat patch. Instructions should be followed closely when using a patch.
We hope that this information is helpful to ensure that your boat is seaworthy for many more years to come.