View Full Version : Watertight Wooden Bulworks Stanchions

11-07-2010, 06:16 PM
I didn't want to highjack the thread this picture was originally posted on so I'm reasking my question here...

I've been considering installing these on my Kahuna instead of using bronze deck-mounted brackets for the bulworks. I've been curious about how to form a watertight seal on a cold molded plywood deck. Matt indicated that the purpose of these wedges is to form the seal so I'm asking if this is appropriate/needed for my boat. Just learning, Scott


wizbang 13
11-07-2010, 06:26 PM
I cannot believe those will ever be watertight. Gonna caulk em with cotton? gonna FG them ? gonna put sika dookee on em?
Besides, I've seen boats that went aground and the bulwark /timbers hung up on the dock, then the friggin covering board was lifted!
Strip planked bulwarks may work for you. Engineer the bottom plank to be fat, (lots of epoxy area) and decrease thickness quickly as you come up. They can be very strong WO risking the deck integrity.

Ian McColgin
11-07-2010, 06:44 PM
In general it's not good engineering to carry structural members above and below the gunnel. If those are frames sticking up, you've got a terrific way to push minor damage, maybe not even damage so much as a brief deflection, from a hard docking down to be cracked frames.

Boat with bulworks will back them onto frames that are almost the same size as the boat's principle frames, but they stay above the gunnel.

It's really hard to design wooden stauncheons that look even marginally in porportion and are actually strong enough.


Roger Cumming
11-07-2010, 10:01 PM
My old boat (5 ton yawl) had high bulwarks supported by stanchions the same size as the frames which were set clear of the frames (between them) extending several planks down from the covering board. Where they pierced the covering board a caulk joint was formed and filled with what looked like Boatlife. In the 15 years I sailed the boat not one of these joints ever leaked, although there were other leaks (mainly between deck and cabin trunk). I attribute this to very high quality workmanship by the builder. These stanchions were detailed to be replaced with a minimum of fuss (no epoxy or any other glue) and also (I think) to give a little when the boat came alongside a dock. This is just good old fashioned high quality construction. They looked right, too - not too big or too small.

Ian McColgin
11-08-2010, 09:44 AM
To clarify a thought that, given Roger's remarks above, I might not have made correctly - I'd not heard of the wooden frames holding up bulwarks as "stanchions" before. When I gave a knock at wooden stanchions I had in mind free standing uprights that support life lines or sunroof or such. Most bulwarks are set against wooden frames and that looks right. The description of running those bulwark frames through the covering boards and down a couple of planks is normal and usually results in an outer face of the bulwark a bit in from the shear strake, due to the bulwark being a nudge lighter than the shere strake, and that looks right. Also common are bulwark frames that land on the covering board with the base to prevent athwartships movement being essentially the depth of the frame plus the thickness of the bulwark. This is a nudge weaker than running through the covering board, but it's way more than strong enough and if broken results in less damage to surrounding hull structures, especially little or no damage to the shearstrake/shelf/clamp/deck.

Both are normal practice in quality vessels and much depends on the size of the boat and exactly what the bulwarks are meant to do. For example, supporting bulwarks that, while not toe rails are only a little more than lower calf rails, run a inch or so above the deck the whole way and thus allow both maximum egress for deck water but also maximum inlet, is a different proposition from bulwarks that are built with freeing ports.

Sometimes similar terms can apply to enough different ways of doing things that confusion can ensue if one is too dogmatic that one's way is the one way.

That caveat aside, I have seen boats with at least some frames brought up past clamp/shelf/shear and they all suffered as a result. And specific to this and put very bluntly, any frame to deck joint that utilizes wedges is inherently bad because the bevel of the wedge leaves a gap some little bit below the surface, a nice gap for rot inducing moisture to gather. It's indifferent workmanship by someone who might make a nice cabin in the woods but is not a boatwright.


Cecil Borel
11-09-2010, 07:28 PM
Scott: I faced the same issue. It is very tempting to use the ring frame projecting above the sheer to anchor the bulwark. As I got to the point of putting the decking down, it was clear that the frames were in the way, and would be hard to work around, let alone seal-up. The frame projections were good staging for forming the bulwarks and deck-cabin beam, and probably should be left long enough to form these elements. I cut the projections off, after this, and put the decking layer over top. Bronze bulwark brackets are not that hard to do.

11-09-2010, 08:03 PM
Hi Cecil,

I chose not to use ring frames in my Kahuna, opting instead to use a combination of permenant and temporary bulkheads as molds. Thus, If I go with wooden bulworks supports they would not be an extension of the frames, or even sistered to existing frames.They would only be epoxied to the upper 18"(?) of the hull, only there as supports for the bulworks. My thinking was for the strength they would provide for safety but also for aesthetics. After reading some of the comments above though, I do have concerns of how an initial minor dock-bump could transfer into hull damage. Plus the problem of sealing out water... Bronze brackets may be best all around. I was impressed with the work you've done so far. Since I only live a few miles from the Wooden Boat School, I may take their bronze casting class.