Pilothouse window design

Hello all,

We have added a pilot house to our former center cockpit ketch. Everything so far is working out well with the new interior layout. However I have run into a mind block on how to design the windows.

Pilot house structure is laminated plywood with opening for windows and doors cutout. I have built frames from sapele to fit into the window openings so that there will not be any raw plywood edges near window edges.

Of the three across the front, the center one I want to have a two piece window with the top half being a swing open from the top. On each side of the center will be a fixed window.

On the sides the forward window will be a removable but not swinging, same goes for the aft window on each side.

I can find plans and sketches for every other thing imaginable on a boat ( and a few things that I cannot imagine having a place on a vessel) but nowhere can I find sketches or designs for this type of window.

I have several reference books that show this type of window, but no details on how it goes together.

Any and all help would be appreciated.

 

The upper half of the middle is called an awning window, I think. To keep it sealed, it's a good idea to have two ways to keep water out. Labyrinth, and gasket. The labyrinth drains at the bottom, and he gasket goes all around.
On the inner face, the area closest to the window can be flat until past the gasket, and then grooved maybe 1/2" to accept a frame-mounted tongue facing outward. The tongue can extend around the bottom too, except with a drain scupper located at a low point.
The outer (fixed) face, then, is plain except for a raised tongue about halfway across the face. If the outer face is 2" wide, the gasket (attached to boat) can be 3/4", half as tall as the spline or tongue, which could be 1/2" wide, and the remaining area outside of that 3/4". The spline/tongue is rounded to encourage alignment. Further refinements would be an outer frame as thick or thicker than the window, or insetting the window frames depending on style, etc..

Alan


The window itself is similer, but reversed, with a groove

 

Alan,
Thanks for the info. I will post a couple of pictures that will better describe what I have done so far. I think I understand the jist of your description.

I am just struggling with how to incorporate it into a removable window assembly.

Darr

 

http://seamac.co.nz/1800fixed.htm
I used to use these, maybe something like it near you, they are excellent pass survey too

 

I see. The outer frames are in now. The question is whether you can inset a seat at least an inch and a half wide (causing your frames to appear rabbeted)---- at a depth the same as the thickness of your window "sash".
Then the tongue can be 3/8" wide, positioned to allow 1/2" to the outside, and 5/8" for the gasket inside (the gasket should be purchased before any wood is cut, of course, to ensure availability and to build around its dimensions). An aluminum tongue is actually a better choice, angle section (1/8" x 1/2" x 3/4" e.g.) even better with welded corners, so that it can be screwed to the flat rabbet face and the gasket can hide the screws.
This also allows a slightly larger glass area, as it requires a smaller rabbet and hence window sash.
Probably should finger joint the window frames too, for strength, with epoxy, and if you have time, fiberglass cloth under varnish to seal and strengthen the whole sash. They take a real beating.

 

Traditional frames are bevel mortised, usually pretty shallow, then screwed or pinned (picture frame style). They incorporate the rabbit from the glass and has either a rubber gasket (on of several types) or are set in goo and have a quarter round tacked over to finish the look. Some use a seperate metal track and gasket to capture the glass.

These types of frames have a tendency to "rack" especially if supported by a single strut when open. Moisture content changes also can play havoc on the joints.

After breaking a few pieces of laminated glass in my Chris Craft, which has a very delicately built frame, I swore to solve the problems. My solution was to make a composite frame with an inner core of plywood and an outer skin of mahogany, which included the rabbit.

The frame is cut from a section of plywood, less the thickness of the mahogany around all edges (I used 1/4" thick harwood). The plywood is stable and doesn't move with changes in moisture content. The mahogany is laminated to both sides of the plywood, sandwiching the "core" with epoxy. The glass still rides in a rabbit and rubber gasket, but I elected to use the "spine" style of gasket (like used on older car windshields) which really tightens the glass firmly to the rabbet. The spine gasket uses a piece of metal or plastic in a slot, on the outside of the window. The glass is easily installed without this piece in place and dropped into the frame, then the spine is pushed in, which spreads the gasket against the glass and frame at the same time, sealing it tight.

I've used this technique on two different boat window frames, a Lyman and an old Atkins cruiser. None have moved a lick and appear as built. The oldest version is 7 years and working well.

A metal core could be substituted (aluminum). With some fancy brake and welding effort, could also incorporate the flange for a rabbet. This type could be screwed together without epoxy, but then you'd have to contend with bungs or exposed fastener heads.

 

Limited Depth of Rabbet

Ok,
The frames are assembled, but not mounted into the pilot house yet.

I can only seem to find a rabbeting bit that will give me a 7/16 in shelf.

I guess I can go one of two ways.

Put the rabbet 3/8 in deep (limited due to channel that sides of frame go into on opposite side) I could then put a rabbet on a piece of 1 3/8in. wide stock and develop the 1 1/2 in wide shelf.

Or I can not put a matching rabbet on the 1 3/8" stock, simply mounting it directly below the existing frame face, developing a two level shelf. Upper shelf being 7/16 in. then a 3/8 in. drop to the remaining exposed 1 in. (approx) lower piece. This develops two 90 degree corners to divert a driven spray. I think I can successfully put a large gasket around the window frame that will come in contact with the exposed 1 in. lower shelf to stop the rest.

Thoughts, suggestions, etc.....

Now onto the mating part of the frame, I will most likely have to do half lap corners with wooden dowels to pin them in place. I think out of all the windows over half of the corners are not 90 degrees.

I am curious for more information from the member who laminated the frames up around plywood. Certainly sounds stable, but how labor intensive, I have 12 to build.

 

It's more involved, but it produces a bullet proof, non-racking frame, which was the point. I use a similar technique on wooden powerboat transoms, where the inner and outer skins are oak planks, but are sandwiching a plywood core, which keeps the planks stable and the transom rock solid. It looks just like a double planked transom, but is much stronger and longer lasting. Think of it as a plywood core, sheathed in the finish veneer of your choice. Raking of large opening, wooden frame windows is a real problem. They look great at first, but soon after some serious use they rack (parallelogram), pull at their fasteners and joints and stop fitting well. Leaks follow and they start looking like crap with open joints and moisture stains.

If you have substantial gluing area and half lap the corners, plus use full and true encapsulation techniques, you may stave off racking for some time and the epoxy will seal the frame from moisture.

If you'd like to drop me an email (click on my name) we could discuss it in better detail.