Drilling and sealing a transom

[two stroke mick]

A read on this forum how important it is to seal a transom. I hope to be drilling mine shortly to install an A frame (yet to be designed) and I will also need to install a transducer for a fish finder. I know this is going to sound like a stupid question

"how do you drill a transom for a self tapping screw and ensure that it is sealed?"

"What is the best way to install bolt holes for an A frame and ensure they are sealed?"

[Nos4r2]

Sikaflex 291. Fill the holes with it and coat the screws/bolts with it too. Wipe off excess after installation (but before the Sikaflex sets) with acetone. Wear rubber gloves when using Sikaflex (and obviously when using acetone)-it sticks to skin very well. Jewson sell general hand wipes that will remove small amounts from skin-just look for one that removes silicone sealer.

[two stroke mick]

Thank you Nos

[mike-stgt]

Hi there, be sure to drill the hole 1-2 mm larger than neccesary.
With self drilling screws, drill the hole not to small, because the tension in the material around the hole will break it after some time.
The holes for the normal srews need to be a little larger, because sikaflex
needs a minimum of thickness to be stable and proof.