Floor fillet question

[mark48]

Hi all,

How are PS builders addressing the keelson joint seam running through each floor's quarter-round gap (port and starboard)? The floor-to-bottom-panel joint receives a fillet which ends short of the gap (as do the bottom-panel-to-keelson and keelson-to-CB-trunk joints), to enable the fiberglass to transition smoothly from one surface to the next. But the keelson joint running through each floor gap needs epoxy too - if for no other reason than this is where any water will go - and yet we don't want anything plugging the gap (e.g., stray thickened epoxy).

I've considered mixing up epoxy, thickening it with only small amount of wood flour such that the mixture flows, and then pouring it along the bottom-panel-to-keelson seam, allowing the liquid to flow through these gaps along the joint line but I'm interested in how others addressed this before I make an awful mess.

Thank you all,
Mark Nunlist

[ddemasie]

I am not totally clear what you are asking, but here is what I did in that spot:

I considered that joint (in between each of the floor supports from CB trunk - across the keelson width, to the bottom hull piece) to be a critical seam - I wanted it to be completely water tight and the strongest on the boat. Because that seam will virtually never be observed (it gets painted and the floorboards cover it completely from sight) I was not concerned about how it looked. I did a total of 3 fillets there - 1 that covered the keelson to CB trunk attachment when I was putting the keelson together - another between the keelson and the hull bottom when initially stitching and gluing the hull bottom on.

Then after I began my final filleting on the floorboard supports, I added a third, very wide fillet between each of the floor supports - that covered the entire distance between the Centerboard trunk, across the keelson and overlapping onto the hull bottom. I wanted every inch of that covered with a wide fillet. I tried to be very careful to do a good, smooth fillet (and sanded it thoroughly with a corner sander) because you do lay fiberglass over it when fiber glassing each of the chambers between floor supports that reaches from the CB trunk all the way across the keelson, across the bottom hull, and onto the side hull panel. After it all set, I did have to do some minor drilling to ensure that there is at least a small gap at each of the 'floor support to CB trunk to keelson/hull' so if water did get in one of the chambers - it had a channel to drain to the lowest part of the hull - as designed (I used a Dremel tool with a flexible attachment to get those holes carefully opened).

I wanted that entire seam to be super strong, and I think I met that objective.

Also keep in mind - there is one more chance to strengthen that "CB trunk to keelson to hull bottom" joint when you flip the boat over and fiberglass the entire hull exterior much later in the build. I did something similar there too. Of all of the joints on my pocketship where separate pieces of plywood come together, I can definitely say that one at the bottom of the boat where those 3 pieces meet is the strongest in my entire build - from both the inside and the outside - I believe that mine will not leak, and it will not break there.

[mark48]

Hi Dennis,

Thank you very much for your thoughtful reply. Were I to reassemble the hull, I'd follow your plan. However, I am beyond that point in that my CB / keel assembly is glued, and the keelson is permanently glued to that CB / keel assembly. The hull (bottom and side panels) is wired and filleted - including the bottom-panel-to-keelson-to-CB-trunk joints between each floor, but I have been trying to keep the "limber holes" clear through each floor (port and starboard) to preserve water drainage and have thus not filleted the ~ 1" gap traversing these limber holes. In retrospect, the smarter idea is to glue the joints in question and subsequently drill out "new" limber holes through any epoxy which interfered. I have no concerns about the strength of the keel-to-CB-trunk joint assembly so far, nor the bootom-panel-to-keelson joint between floors, but I'll proceed to fillet the remaining short spaces traversing each floor.

Any other thoughts are welcome, and thanks again.
Mark

[truenorth]

I think you've hit on one of the more problematic parts of the build. It's too late now, and was too late for me, too, but when I came up to this part, I realized that I should've epoxy'd the keelson and bilge panels before installing the floors. In the end, it didn't matter *that much* but it took some work to make me feel good about the solution. You've mentioned it already: try mixing up some thinner epoxy and applying it liberally at these joints. You're going to have to re-drill, anyway, when you 'glass these panels, so don't worry about filling the limber holes. I used a finger dipped in epoxy.

In hindsight, this blog post isn't as helpful as I thought it was at the time, but the gist of what I'm trying to say is here. The sixth photo down is a good shot of it.

http://sunmonkeypocketship.blogspot.com ... gress.html