Thursday, April 24, 2014

Hatches and Secret Passageways

Starting with the stack of hatch opening reinforcements and hatch stiffeners from my last post, I have laminated, cleaned up glue squeeze-out, trimmed, rounded corners and edges, and sanded until I've had about enough of that for a while!  But now they are all ready to go.

Here's a pile of laminated hatch stiffeners on the left and the port seat hatch reinforcement on the right.

Here are the cockpit sole hatch opening reinforcements ready to install.

And here they are clamped up waiting for epoxy to cure.  I made these PVC pipe clamps about 15 years ago when I built my first kayak.  The idea is from Chesapeake Light Craft, and they are made from 4" schedule 40 PVC, cut about 1 1/4" wide, and then cut so they can spread open.  They work well, and are cheap to make.  I find they are best clamping about 1" thickness, they are a bit less effective on this thinner glue-up, so I used a bunch of them.

First coat of sealing epoxy is on those now.  I'll sand the fuzz off and put a couple more coats on before this gets installed.  Same progress with the hatches in both seat tops.

I've also started gluing on the hatch stiffeners to the back side of the hatch lids.  As with the hatches I did for B3, there is some twist in the plywood, so I twist it a bit the other way (see the 4 mm spacer at lower right) and glue it up.  I try to guess right with the spacer so that when unclamped it springs back until it's flat.

As I was doing all this hatch work I was thinking about drainage.  I was thinking that the cracks around the hatches in the cockpit sole are likely to get filled with water in the normal course of events from wet swimsuits climbing in, rain, overflow from filling the ballast tank, etc., and that water would fill the cracks and stay there until it drains into the storage areas if the hatch gets opened.  It seemed to me that could be irritating.

I have seen others rout a channel the full depth of the sole doubler (the top layer) to allow that water to drain away.  But I didn't like the look of that.  After a bit I came up with my idea of "Secret Passageway" drainage!  

I routed a drainage channel on the underside of the sole doubler leading from one corner of the hatch opening to the gutter that runs down to the sump in the rear of the boat.  I cut the channel about half the thickness of the plywood, and angled it back at a 55 degree angle.  The sole has a slight tilt towards the rear so water should drain through here by gravity.

The openings are pretty much invisible, and the cockpit floor is undisturbed.

If these would ever get plugged with gunk it should be pretty easy to poke something through there from the hatch opening side to clean them out.

These channels will be well coated with several coats of epoxy to prevent water from seeping into the plywood, and I'm making a special tool (ok, basically a rounded stick) to run through the channels as I glue the two pieces together, to clean out any thickened epoxy that squeezes into the channel and would block it. 

I think this is going to work nicely.  Any other SCAMP builders that want to borrow the idea please feel free!

July 27, 2014 addendum - I had a question in the comments about the router and templates I'm using for some of the build sequence, so heres' a shot of the Porter-Cable router.  I've had this for probably 20 years - I don't know if they still make this model (#693 with a #6931 plunge base)

Here's a photo of the bottom with a template guide bushing installed, and some of the other spacers that I've used on this project: 

And here's a shot from above showing the knurled ring that fixes the template guide in place.

Wednesday, April 16, 2014

Cutting cockpit sole and seat top hatch openings

With the hull panels now installed, I put a coat of paint on the inside, and will show a photo of that when I've got the final coat done.  I took a little break from painting and turned my attention to constructing the remaining hatches in the cockpit sole and the seat tops.

I used the same technique I described earlier in > this blog post <.  I used all the same template guide bushings and reused the template itself for three of the cockpit sole hatches and for the hatch on the port seat.  I needed to make additional templates for the ballast tank opening, the starboard seat top hatch, which is narrower due to the centerboard trunk, and the round openings for the plastic hatches in the back corners of the seats.

I took a while to finalize the locations of the cockpit sole hatches, measured (several times!), and started making sawdust. 

Here are the holes completed in the top layer.   These were cut out with a 1/8" bit, and I plan to use the sections cut out as the hatch covers.

In the bottom layer I cut the holes smaller, and included a groove for the gasket.

And then I spent a few hours cutting all the additional backing plates and hatch stiffeners from 1/4" birch ply.  Lots of changing template guides, collets and bits was involved.

Next up, I will sand off the fuzz and round edges and corners, laminate two layers where appropriate, and install them.

Thursday, April 10, 2014

Hull panels done - some fisheye fun!

To finish off the hull panels, I taped the joints between the hull panels and bow/stern transoms, and trimmed the panels off flush with the ends of the boat, which looks nice.

Next I vacuumed out the hull and ran a tack cloth over it before coating the interior of the hull panels with their third and final coat of epoxy.  I had applied the first two quite a while ago when the panels were flat on the bench.  I used a roller, and then tipped out the bubbles with a foam brush.

Then I grabbed the fisheye lens for my camera to take these shots, which accentuate the nice curves on this boat!

After the epoxy cures I'll remove the gloss by hand sanding with a sanding sponge, then will apply two coats of white paint to finish off those interior areas.

Sunday, April 6, 2014

Final hull panels installed!

It's been a productive weekend - I finished installing the final hull panels, and now this is really looking like a boat.  

These panels were the easiest of the bunch.  I fit the panels, then removed wires front and rear and loosend those attached to bulkheads 3 and 5, the hull panel lifted up and stayed in place leaving lots of room to apply thickened epoxy to the lap joint: 

After applying epoxy, I pivoted the panel down and reattached the wires.  I added a few through the lap joint to make sure I had good contact the length of the joint.  These ties I bent to the shape of a big staple, drilled two holes, inserted them from inside, and twisted on the outside.  Worked very nicely.

I let the expoy cure, then removed the wire ties that were no longer needed in the lap joint, and filleted and fiberglass taped the inside joint.  The fiberglass tape on this joint is not required per the manual, but it makes me feel better to have it, so I applied it.

Here's an inside view.  This was taken before I filleted and taped the starboard side.

And here's an outside view.  Looking like a boat!

Mini-tool review - Microplane rasp

This weekend I was looking through the remaining pile of boat pieces, and was pleased to find that they grow fewer all the time - a visible sign of progress. 

Among the remaining pieces I spotted one that I had forgotten about - the cleat that supports the aft edge of the foredeck.  I thought I might as well install this, and went to check the fit on the boat.  I found that I had painted over the gluing area, so I first scraped that area clean.  I then found that I had put some nice substantial fillets around the deck beams on the forward side of bulkhead 2, and so the cutout in the cleat would not fit.

I had a couple options at this point.  I could try to remove the fillets, which would be a lot of work.  I could make a new cutout in the part big enough to fit around the fillets, but that would not be very elegant.  I took the third option - to form the cleat to conform to the fillets, and to do that I called into service one of several microplane rasps that I bought a little while ago.

These stainless steel rasps have lots of very sharp tiny cutting edges, and come in fine or coarse in several different profiles.  They work great.  The company's web side is here if you'd like more info: Microplane Rasps 

Here I'm using a coarse, square profile rasp to shape the deck cleat cutout. 

Here's the final result.

And here's the installed part - a perfect fit!

These tools also work great on cured epoxy.

Centerboard uphaul tube installed - makeshift flaring tool

Before I finished installing hull panels, I wanted to get the centerboard uphaul tube installed, while it was still easy to work in that area.  This tube lines the hole that the rope runs through to raise the centerboard, and prevents wear to the hole and to the rope.

The uphaul line is 1/4" diameter, so I got a short length of tubing from the hardware store that is 5/16" ID, and 3/8" OD.

First, I drilled the hole.  I wanted to ensure that the hole was perpendicular to the bulkhead, and didn't tear out on the far side.  So I drilled a hole through a scrap block on the drill press to use a a drill guide, and clamped another block on the inside of the centerboard trunk to prevent tear-out.  I drilled a pilot hole and then followed that up with a 7/16" bit.

I cut a short length of tubing, flared the end, and inserted a length of 5/16" dowel and taped it on.  This let me manipulate the tubing, rotating it to apply thickend epoxy and pulling it through the hole. 

I clamped it in place with a stick until the epoxy cured.

Here's the inside, flared edge.

And this is the other side.

And this shows the 1/4" uphaul line exiting the tube.  At this point I considered leaving this as is and calling it done.  The rope pulls straight out of the hole and into a turning block, so I think that would work fine.  At this point the flaring tool doesn't work, and trying to shape it with a ball pein hammer seemed likely to mess things up.

After some thought, I started rummaging around in my 1/4" bolt bin, and found this flat-head machine screw.  My plan was to insert this through the tube with a washer and nut on the inside and flare out the end by tightening the nut in a controlled manner.

Here's the screw Inserted in the tube.

And the resulting flare after tightening up the nut a bit.  Worked great.

But it was sticking out a little too far, so I sanded it back using a little disk in a die grinder, and flared again.

And then I did follow up with a little light tapping from the ball pein hammer to fllatten it out just a bit more.  Job done!

Wednesday, April 2, 2014

More hull panels and a Whoops!

I have continued to install more hull panels, and it's been rewarding to start to get a more complete feel of what this boat will look like.  

After applying a panel I come back about a day later and hit the edges of the fiberglass tape with a scraper to smooth off the rough edge.  The tape has a little structure at the edge that sticks up and is rough, and one edge is worse than the other.  The scraper made quick work of it.

And after vacuuming up the shavings we see this.  I don't intend to attempt to further smooth this out.  It's inside the storage area, and all I care about is that there are no rough edges to snag anything I store in there.  the inside of the hull panel and fiberglass tape will get one more coat of epoxy to ensure all is sealed, and then two coats Rustoleum Gloss White to finish it off.

I found that the front of the garboard panel curved across the center line due to the keel from the bow transom down to the bottom of the hull having a slight curve.  

I used a plane to trim that panel back to the center line so that it would not interfere with the panel on the starboard side.

I then took a look at where the material was removed, and how much was taken, and got out the spokeshave to make the other side look the same

After installing the panel, the front edges meet up nicely. 

Moving on to panel number two, things got a little more difficult.  The bottom hull panel rested against the hull bottom, but panel 2 doesn't have that luxury.  I ended up suspending the panel with some thin nylon straps to get it roughly into position, and then wired it on in a few places.

I then took out some wires and loosened others.

This left the hull panel hanging loose enough so that I could get under there to apply thickened epoxy to the lap joint and then tighten things up again.

So, current status is four hull panels installed, filleted, and taped.

And it's looking like a boat!

But alas, all is not perfect.  I got so into getting hull panels installed that I forgot I needed to use the seats to align the bulkheads.  I've had some issues with this plywood in that the pieces tend to warp and twist somewhat.  Not sure why that is, but the net result in this case is that all the bulkheads no longer line up with the slots in the seats.  Whoops! 

This is the worst one.  Looks like I'll need to open up the slot on one side, and fill it in with epoxy (wood flour fillet mixture) on the other.  Should not be a big deal, and the hull panel shape looks good.

My wife consoled me, saying that no one would ever notice as long as I didn't blab it all over the internet or something :-)