which caulking is acceptable

[995jim]

Hi. when I go to reinstall screws to attach a bracket on the outter face of my transom on my fiberglass boat which of these caulking choices is best to leak seal
butyl
rtv silicone
marine silicone
thanks jim

 

[dingbat]

Hi. when I go to reinstall screws to attach a bracket on the outter face of my transom on my fiberglass boat which of these caulking choices is best to leak seal
butyl
rtv silicone
marine silicone
thanks jim

3M 4200FC