Eastport Pram Skeg Installation

Builder's Forum
1

I was comparing the manual between my Eastport Pram and the Passagemaker, specifically the section on installing the skeg.  A few questions about the best approach.

1) - the passagemaker instructions say to sand the hull surface where the skeg will attach and shows a picture of the fiberglass coating sanded clean through to the wood while the eastport manual does not say anything about this.  How important is this step?  When considering the screws and the fillet that will hold the skeg to the boat, it seems like maybe a light sanding will do?

2) - a lot of people talk about drilling over-sized holes for any screws that are going to be below the waterline, filling said holes with epoxy, and then redrilling the appropriate sized pilot hole in the cured epoxy.  I guess this is to prevent water intrusion.  Is this important?  If so, then why isn't it mentioned in the manuals?

3) - what is the right sized drill bit for a pilot hole for a #8 screw?  Should the bit be smaller or the same size as the shank of the screw?

4) - the passagemaker manual mentions countersinking the #8 screws when installing them.  Is the assumption that the pilot holes should be hit with a countersink drill bit on the inside to allow the #8 screws to sit flush on the surface of the inside?  And then filled over with more epoxy?  The heads of these screws seem to be invisible for both the skeg and the skids in pictures on the web.  What's the secret to hiding these on the inside of the boat?

Thanks.

2

Add all epoxy coats to the bottom before installing the skeg, then you won't have any issues with the glass.  It's also easier to roll on without the skeg and skids in the way.

The slotted screws are very appropriate for the old-school builders.  I've never had any luck with them and they blow out on me, hence the Frearson bits.  With that being said, I would use them for installing the oarlocks, regardless.  The domed top gives them more meat for the screwdriver to bite.  In almost all applications, I prefer oval head screws.  They just don't work very well for a flush installation.

Always use the properly sized counter sink (e.g. #8, #10, #12, etc.).  Don't make them any deeper than they have to be.  To check, I'll flip the screw upside down and see if the top of the head fits into the hole.  With only 6mm to work with, every mm counts.  Hooper makes an interesting point that I never thought of though.  I use plugs for furniture making to hide screws, but I never thought they needed hiding.

Yes, good catch, cut out the daggerboard slot before installing the skeg to give you full access all the way around the slot.  My skeg butts right up to the edge of the slot.  I used a 1/8" round-over bit in the router to ease the edge after using a patterning bit to follow the inside of the case.

 

 

3

   While I'm at it - how perfectly does the mating surface of the skeg need to match the curve of the hull?  Are small gaps ok considering the eventual fillet that will cover them?

4

1.  Depending on how long between epoxy coating the hull and installing the skeg, you might have to sand.  This is dependent on the epoxy, so check the manufacturer's recommendations here.  To be safe, light hand sanding to scuff the cured epoxy is highly recommended.  This provides a mechanical bond in addition to any chemical bonding that may occur.  Do not sand into the fiberglass.

2.  The drill-fill-drill concept is an automatic, no-duh, slam dunk.  Get into the habit.  Use 5 minute epoxy for these if absolutely necessary but do it always, religiously, or you'll be praying you had done it...

3.  For wood, pilot holes, should be the same size as the shank of the screw, not counting the threads.  You can hold a drill bit up in front of a screw and if all of the threads are sticking out, then you've got your pilot hole size.  There are also tons of online charts for those, but I think it's more important to know how to do it manually, the old-school way.  This method gives you maximum bite of the threads in both pieces of wood/epoxy.

4.  Countersink your flatheads so they're flush with the bottom of the boat.  Then as you epoxy over it, they'll get sealed and be flush.  This is the same whether you're painting or leaving the interior bright.  This brings up an important point.  Make sure you use silicon bronze screws here, not stainless!  Stainless loses it's stainlessness when deprived of oxygen (like when it's encapsulated in epoxy).  Silicon bronze screws have been used for boat building since the first time a boat builder threw his beer bottle into the smelter.  Not kidding here.  This leads us to the next most important thing, don't use Phillips head screwdrivers on your silicon bronze screws.  Get a Frearson bit, which will bite better into the softer material.  As stated above, my interior is finished bright and I love being able to see the silicon bronze screw heads sunk into the wood.

5.  I built from plans and my skeg fit pretty nicely along the curve of the bottom's rocker.  The first step is to "butter" the edge of the skeg that's mating with the bottom, so any gap <1/8" should be acceptable.  After screwing the skeg into place, I ran huge fillets along both sides for more lateral stability.

Hope that helps.  Check out my build blog:

http://www.midnight-maker.com/single-post/2015/08/18/Mancraft-101-Building-the-Eastport-Pram

5

   Thanks CaptainSkully.  I have seen and enjoyed your build blog!  What luck being able to ask you questions directly.

At this point I've only done a single epoxy coat on the fiberglass on the bottom of the boat, so any sanding is going to skuff up the fiberglass I suppose.

Also, the bronze screws supplied with my kit are flat head slotted and have a slightly domed top, which seems to me to be about the worst type of screw you could have for driving, and for making flush.  Perhaps I'll run out and get some better screws.  Did you find it necessary to use a countersink drill bit to create a counter sink hole when driving the screws for the skeg, or did you just drive them until they stopped and rely on subsequent epoxy coats to flush them up?

I also just realised that I'm going to have to cut the daggerboard opening in the bottom of the boat before installing the skeg, as the proximity of the end of the skeg to the aft portion of the slot is close enough that I'll never be able to get a router into the end of the slot if the skeg is in the way.  The manual doesn't mention this.  The manual doesn't mention a lot of things.

Many thanks!

Thom

6

The screw heads could have a decorative look in the bottom of the boat. For my Skerry, I countersunk them slightly below the surface and cut paper thin plugs to cover them. Durability is not a concern as it is glassed over. You have to look for these screws to find them and when you do see them, they have a very “finished” look. Hooper Williams - Brevard, NC