Blower vent removal

I am not a fan of holes in the side of a boat which are not part of a closed system.  If water goes up a closed system like the generator exhaust, air conditioner water raw water outlet or even in a worst case, the gas vent, at least it doesn't go into the bilge.  In the case of our boat, someone had cut a big fat ugly hole in the side of the boat only about 24" above the water line and then connected an old rectangular bilge blower to the hole.  The blower unit was corroded badly but it still ran.  Still, we would find another way to vent the bilge during engine start that didn't require there to be a big ugly 6" by 4" hole that was covered by a cheap looking louvered plate.

As with the holes in the bottom of the boat, this hole was scarfed although not nearly 12:1.  But it's really not taking any load so I am sure that the contact area will be enough to hold, especially with the use of West Systems epoxy.

Due to the size of this hole, before we patched the front of it we pulled a piece of epoxy soaked cloth across the backside and let it cure.  This gave the patch something to push against when laid in place from the outside.

A layered, tapered patch was created, same as it was for the holes in the bottom, and the hole was gooped up with epoxy resin.

The patch was then squeegeed into place using waxed paper to protect the top layer of the patch from being moved around relative to underlying layers by the squeegee.  We made sure that the ridge in the middle of the hole was filled without voids. 

When we placed this patch, the outside temperature was at the low end of the allowable range.  Thus it took all night to cure to any degree.  As we checked on it over the next couple hours we noted it was slowly sliding down the side of the boat under its own weight.  In order to lock it into place, we taped a masonry trowel which had a lot of surface area on top of it and let it set overnight.

We were lucky that the patch was not fully cured the next morning or we might have had to grind that trowel off of there.  But with some effort we coaxed the trowel free without hurting the patch.

The patch was later sanded and faired and is now ready for gel coating.

Some might be curious where the bilge blower vents were relocated.  We decided to go with twin inline blowers that connect to these stainless louvers, one port and one starboard, that would probably be mistaken for courtesy lights at first glance.  They are up out of the way and all fumes are still discharged outside of the cockpit.  The are up high and safe from water intrusion and have been through many strong storms in the marina already without blowing any water back down into the bilge.  This spot almost looks like it was made for the blower vents.

Click here to see how we handled the rotten toe rail.