Installing Seacock Pad for Flush Mounted Thru-Hull (Replacing Thru Hulls and Seacocks – Part 4)

All the original Morgan 382 thru hull fittings were flush with the exterior hull.   To accommodate the exterior flange of the flush thru hull fitting, raised areas of fiberglass protrude into the interior of the hull.  On Pilgrim we decided to reuse one of the original flush mounted thru hull sites, the head sink drain.  Creating a seacock pad atop the interior protrusion proved much more complicated than installing the seacock pads in other parts of the hull (see Four Out of Five Seacock Pads Install Easily)

The process began by creating a plug to prevent the interior epoxy work from fouling the exterior recess.  The exterior recess must mate well to the mitered flange of the thru hull fitting to ensure a water tight fit.  Allowing excess epoxy to mar the exterior surface must be avoided.

Top:  The duct tape wrapped PVC pipe used to temporarily plug the existing hole in the hull.
Bottom:  The new marelon recessed thru hull fitting

A scrap of PVC pipe closely matched the outside diameter (OD) of the existing hole in the hull.  Adding a few wraps of duct tape ensured a snug fit and covered the hollow end of the pipe.   Epoxy does not create a strong bond with either side of duct tape so taping over the pipe will also make it easy to remove once the epoxy has cured.

The exterior view of the hole with the plug inserted.

Inserted from the outside the PVC & duct tape plug fit the hole well.

The interior view of the hole with the plug in place.

With the hole in the hull plugged, I headed inside Pilgrim to install the first layer of the seacock pad.

The seacock pad for this site consists of two layers of 3/8” G10 board.  The first layer has large hole in the center to accommodate the bulge in the hull.   Layer one was set in position using epoxy thickened with a combination of microfibers and cabosil.

The first layer of the seacock pad with grey epoxy filling the center cutout.

After allowing the epoxy  to cure overnight, I washed down and ground smooth the first layer of the new seacock pad.

To maintain proper alignment of top layer while the epoxy cures, I plan to insert a ¼” machine screw through a pilot hole in both layers.  The ¼” hole is ideal since I have plenty of ¼” machine screws around and the hole diameter matches the size of my hole saw arbor bit.     It is very important the ¼” pilot hole be centered precisely in the existing hole in the hull as it will serve as a guide when boring out the seacock pads to accept the new thru hull fitting.

To precisely locate the center of the existing thru hull hole, I hand turned a hole saw matching the diameter of the thru hull hole in the original hole.  The tip of the hole saw arbor bit marked the center of the original hole.  Using the center mark on the outside of the hull as a guide, I drilled a ¼” hole through the new layer of thickened epoxy that now filled the center of the first layer of the seacock pad.

I then went inside Pilgrim and taped the second layer of the seacock pad atop the first.  Then back outside to mark the hole on the second layer with a pencil.  Then back inside to remove the tape.  Then over to the shop to drill the ¼” hole in the pad on the drill press.

Ready to epxoy together the two layers of the seacock pad.

After many trips in and out of the boat, I finally had matching holes in the two layers of the seacock pad.  Waxing the ¼” machine screw used to align the layers prevents the epoxy from sticking to the screw. 

Top Right: The two layers of the seacock pad assembled and curing
Bottom left:  Recently installed seacock pad for blackwater discharge thru hull.

I used another round of epoxy thickened with micro fibers and cabosil to secure the second layer atop the first.  

Exterior view of thru hull recess with machine screw securing the interior assembly.

Next a quick outside inspection  to ensure no epoxy  squished out on to the exterior recess. Now we wait for the layup to cure.

What are those white stripes on the hull? 

Good question!   And one I plan to answer in my next post.

Four Out of Five Seacock Pads Install Easily (Replacing Thru Hulls and Seacocks – Part 3)

Seacock pads for the four mushroom (button) style thru hull fittings are now epoxied to Pilgrim’s hull.

Seacock pad for galley sink drain 

The installation started by drilling a ¼” hole in the center of each pad. The ¼” hole matches the diameter of the hole saw arbor bit that will later be used to cut the larger hole in the hull and pad.   I then placed each pad on the hull in it’s desired location; used an awl to mark the location of the ¼” center hole on the hull; and then drilled a ¼” hole in the hull.

Seacock pad for engine raw water intake now located under quarterberth.

Inserting a ¼” bolt thru both the hole in the pad and the corresponding hole in the hull ensured the pads remained properly aligned while the epoxy cured.

Seacock pad for raw water intake located in wet locker opposite galley

I coated the underside of each pad with a 3/8” to ½” of West epoxy thickened with a combination of 404 & 406 fillers.  When setting the pads onto the hull I ensured a healthy bead of thickened epoxy squished out around the entire perimeter of the pad.

Seacock pad for blackwater discharge located under head sink.  Hole up and right of new green pad is the original recessed fitting for the head sink drain.

The single remaining pad will be installed atop the existing recessed fitting in the head.  The installation of the pad for the recessed thru hull is a bit more complex and deserves it’s own post.

Additional Images can be found in our Re-Plumbing Pilgrim Photo Album.

Fabricating Pads for New Seacocks (Replacing Thru-Hull Fittings and Seacocks – Part 2)

With work on the exterior of the hull progressing along it is time to fabricate new mounting pads for the seacocks.  I am creating pads to serve two purposes.  First, the pads provide a smooth flat surface for mounting the seacock on the interior of the hull.   Secondly, since I do not plan to thru bolt the seacocks to the hull the pads provide a thick stable surface to which the seacocks can be mechanically fastened.

Morgan used 5200 to adhere plywood pads during the original construction. The image below, taken in January, is of the original plywood pads in the head.

Pilgrim's original plywood seacock pads in the head.

Pilgrim's new seacock pads will be created from fiberglass (FRP) board.  Prefabricated FRP board can be purchased in sheets up to 4’ x 8’.  The material is also available in many thicknesses.  I’ve seen it range from 1/8” to 2” thick.  Commercially the material can be sourced under the name GPO3  or G10 Fiberglass Board. 

Fortunately there is a pile of scrap G10 material left over from other projects here at the boat yard.  Attaching the seacocks to the pads via tapped holes rather than bolting through the hull requires a pad thickness of at least 5/8”.  Achieving a 5/8” thickness while scavenging from scrap pile required laminating 3/8” thick pieces together for the larger pads.  I was able to find scraps suitable for creating pads for the two smaller seacocks.

Cutting fiberglass is brutal on saw blades and drill bits.  Only after destroying two blades on my jigsaw did I discover that there are blades specifically made for cutting FRP

The right tool for cutting FRP 

Having the right tool for the job is invaluable.

Cutting, drilling, and sanding FRP creates a noxious dust.  So… always wear a high quality dust mask.

4 of the 5 thru-hulls we are installing will be located in new positions on the hull.  For these we purchased mushroom (button) style thru-hull fittings.  Pads for these thru hulls were relatively simple round or square shapes. 

Rough cutting the G10 Board.  The two discs at top will be laminated into a single pad.  The two square pieces below are for a recessed thru-hull in the head.

The Morgan 382’s original thru-hull fittings were recessed.  We are replacing one of the original recessed thru-hulls, the head sink drain.  Since the fitting is recessed the interior fiberglass bulges upward around the fitting.  Fabricating a thick seacock pad for this thru-hull required two layers of G10 board.  The initial layer has a circular void in the center to accommodate the hull shape.  The second layer is a solid piece of G10 board.

The pads as they will look when laminated together 

I laminated the pads for the mushroom style thru-hulls together prior to installing them in Pilgrim.  The two layer pad for the recessed thru-hull will be laminated together during the installation process.

Test fitting the seacocks on the completed pads.

Repairs to Hull Damage and Blisters – Part 2

Filling old thru-hulls, blisters, and damage on Pilgrim’s Hull is progressing.  We have now filled in all the areas initially ground out for repairs.

Portside under head after initial round of applying 1708 cloth

I employed a 9” grinder with 36 grit paper to begin fairing the repairs. The larger surface area grinder lessens the likelihood of dipping an edge and removing unnecessary material.

Portside under head after initial grinding.  The area on the right, old thru-hull holes, require additional cloth. 

A couple of the repairs were shy of the original hull surface.   Any area required more than 1/8” of additional material to fill I chose to build up with layer(s) of cloth.  These areas included the old head thru hulls, a blister just port and forward of the keel, and a sizable strip of the large repair portside under the cockpit.

Repair on portside under cockpit requires an additional layer of 1708 cloth in the outlined area.

Above - Area circled in black ink required one additional layer of 1708 cloth.

Below – Area after applying new cloth.

Repair on portside under cockpit with additional layer of cloth applied.

I’m certain as we remove more bottom paint we will discover additional area’s requiring attention, but for now all the areas we have exposed are ready for the initial round of filler.

Looking down the centerline of the hull at ongoing repairs.

I will use a mixture of west epoxy and cabosil for the first round of fairing filler.