One day I closed a thruhole before leaving for a long hiking trip. I had never done this before so Mike explained the safety reasoning & where all the thruholes were on the boat. He explained, if a pipe directly connected to a thruhole were to fail (aka break) & we were gone, it would potentially allow for the boat to sink. I immediately googled thruholes and read this little tidbit of information “A three inch diameter hole twelve inches below waterline can emit 177 gallons of water per hour (gph)…”. I was horrified to realize someone had intentionally put holes in my boat. I understand how silly and ignorant I was but back then this information was revolutionary to my fear of living on a boat. Proof that ignorance is bliss. A week later Mike left for a business trip. This left me on Gaia, on a mooring, by myself, for a week (can you feel the impending drama building???). I tell ya, I surprise even myself at how many things I found to keep me up at night. My Dad would always joke saying ‘leave one foot on the ground when you sleep, just in case…’ . I’m embarrassed to admit I wasn’t that far away from trying it – I mean WHAT IF the bilge pump broke and the VHF radio didn’t turn on, AND the dinghy was stolen…..
Fast forward a boat season or two…..
We hauled Gaia out at Admirals Hill. And while others could slap an undercoat of paint on or polish the hull over the course of a few days, Gaia always seemed to become a semi-permant resident in whichever marina we were being hauled out. This haul-out was no different. This seasons haul-out was dedicated to thruholes or “seacocks”. Mike replaced 5 thruholes, and filled in three we deemed unnecessary, and together we rebeded one stubborn thruhole… (fun story there).
Kirstens brief overview…..
- First step; choosing the thruhole: underwater thruholes shouldn’t be plastic, it’s more expensive but go with the bronz (do I need to remind you how many gallons of water can get through a 3 inch hole?). Plastic, as you may guess, has a much easier breaking point and is more susceptible to extreme changes in cold.
- Second: Once you have your replacement thruholes you’ll need to remove the old ones….. good luck with that. Items required for removing a thruhole are the expected screwdrivers, wrench, and angle grinder and unexpected but most productive was the blow torch.
- Thirdly, clean out the hole, sand lightly around the edge and apply the 42Hundred. 42 hundred is your underwater sealant which retains a bit of flexibility to prevent against cracking.
- To remove and close up a thruhole you’ll need to sand the edge at a slight angle so as to make it a beveled edge. After that it’s all about layering fiberglass carefully to reinforce the hole.
Overall, after hearing it so many times, I admit it…. It’s not as scary as you may think.
Last bit of this story is; Mike replaced and touched up every thruhole EXCEPT ONE (which was a lot). When it was time to put us back in the water the travel lift operator sat Gaia in the water and we eagerly jumped onboard to check for any leaks. “Looks good”, “looks good”, “looks good” rang back and forth between Mike and I as we checked each thruhole with headlamps. I thought we were in the clear and then we heard the bilge pump go off … crud. There was a leak somewhere. Mike shined his headlamp at the ONE thruhole he didn’t touch and sure enough that little bugger was leaking. We had an emergency haul out and we were put back on the stilts. The marina operator gave us one hour to fix it and get back in the water. There was a lot of cursing and blow torch action but we got it done like we always do.