Bungs or Bung mounting Leaks

[PeterInSA]

Prior to taking out our 5m 1/2 cabin it being in our garage unused for sometime, I replaced the old bungs with black washer seals with new red washer seal bungs. I understand that the red washers indicate a square thread and the blue a round thread.

A good 4 hours on the water, back at the boat ramp, a good 3 cups of water came out of the centre bung and two cups of water out of both the bungs on either side of centre. The water was choppy but no waves came on board. The side bungs go into underfloor boyancy tanks with no other opening to the outside, so either the bungs are leaking or I suspect the seal around the bung mounting leaks.

Question1 What sealer do I use to seal the bung mount eg Sellys Roof and Gutter sealant?

Question 2 Do I use the same sealant to coat the timber inside the hole to stop rot?

Question 3 How long will this sealant last, because travelling at a reasonable speed in rough seas on hitting a wave the bottom of the boat must compress the air in the underflloor tank forcing pressure on the sealant around the bung mount and after the wave passes there will be backward pressure to suck in water thru the sealant around/underneath the mount.

Appreciate your comments

[Noelm]

hhmm All I can say is yes to all those things, and not too sure of the exact sealant, but I guess anything is better than nothing.

[100]

maybe some sikaflex as a sealent, but also some plumbers tape around the thread on the bungs them self. helped me alot..

[ozscott]

Funnily enough mate mine were letting a bit of water in also - they are chrome plated brass bung shrouds with c-lated brass bungs - pretty rate these days, but its a 70s boat. Once every few years you just replace the o-ring. I pulled the lot out and cleaned up inside and then inserted sikaflex and then 19m poly pipe and made sure there was a skin of sika where it meets the inside of the bilge area and the brass shroud when put back in...now water cannot ever again touch wood!

Cheers