Project M - Interior Aft Bulkhead

[pokerrick1]

What's this "if you're smart" cra*. Of course he's smart - - -and he can draw too!

Rick

[Currie]

(gulp)....Jeez guys, I hope this thing turns out The pressure's on. I'll do my best. Kevin, good idea. I'll save all the templates and make up a set of plans if it's practical. Makes me wonder how much variation there is from boat to boat. They all came from the same mold...but still.

I'm getting excited about this project.

Cheers,
~Bob

[Terry]

(gulp)....Jeez guys, I hope this thing turns out The pressure's on. I'll do my best. Kevin, good idea. I'll save all the templates and make up a set of plans if it's practical. Makes me wonder how much variation there is from boat to boat. They all came from the same mold...but still.

I'm getting excited about this project.

Cheers,
~Bob

I'll be one of your first customers Bob!
Actually they did not all come from the same mold, hull perhaps, but those interior molds kept changing for the first few years.
The '04 model has the hump behind the ladder whereas the '03 and post '05 do not. The seats are higher in the '05 and newer models whereas the '03 & '04 are likely the same lower height.
I also noticed on the mods page that the bolts holding the pedestal in place had the little access buttons covering them whereas in my '03 those bolts are sticking down where I can bump my head on them so I covered them with little rubber stoppers to soften the bang on my head (I still bump them)
Not sure of the ladder length in various models but you may want to measure that distance from the seat to the cabin top as it will be different from the '05 and newer models due to the higher seating.
I have the wood floor panels in the salon, head and hallway sole (can't think of the nautical term) outside the head, whereas newer models have a complete fiberglass molded floor. Perhaps even the salon floor is of different dimensions in various models.
I doubt there is any major differences between the '03 & '04 aside from the hump behind the ladder. Since the two original models are most similar the plans should work on either model, it will only be the '05 and newer models that will have to modify the plans a bit. Looking forward to getting the plans Bob!

[Paul S]

I mentioned it on the first page.. but the hull flexes A LOT. any firm bulkhead in this area will be a location for stress point . Not good of you are rafted, and have a fender between you and the boat (or dock, etc)..and a killer wake comes by

These are tough boats, but after being woken up at 5am, rafted with another Mac, and having a Maine lobster boat pass leaving a wake of insane magnatude. I could see the hull flex where the fender was, a good 8-10 inches into the boat.. I had to brace myself on the starboard bunk pressing my back onto the hull to minimize the deflection. I was STUNNED how much they flexed without breaking! I was CERTAIN it would crack the gelcoat/fiberglass..but it did not!

Not being a buzz kill, but I would be super careful in creating a bulkhead in an apparent engineered flex area.

Paul

[Terry]

Bob, if you're smart you'll measure and document each step along the way in this project, since I expect you will be able to sell, in classic Norm Abrams' New Yankee Workshop fashion, "a measured drawring" of the project! And if you video it you can sell that as well. Heck, you could even sell the kit parts (less lumber) as well!

(Ya gotta love capitalism.)

Well Kevin, let me give you an example of the epitomy of capitalism.
Garrison Bay, just around the corner from Roche Harbor on San Juan Island PNW.
This is the location of the historic Bay of Pigs War Tensions that took place between the Americans and British, an historic monument to be sure. I had the oportunity to visit this famous location summer of 2006 and could not believe what I discovered. Here was where the British built an entire garrison and kept a fleet of ships and built a full community of buildings including a school house. In the last remaining building the Washington State Parkies were doing a slide show presentation depicting the historic times of the settlement. They showed images of all the buildings that were there during the time. At the end I asked the uniformed Parkie what happened to all those beautifully engineered structures and she explained to me that during those times it was most profitable to dis-assemble the buildings and sell the lumber for money. Wow! Capitalism at its' finest! If it had been me having to explain this to a tourist I would be too ashamed to do so. Such an important piece of national history sold for profit, I was totally agast and felt quite disappointed that such a thing could be allowed to happen even if it was over 100 years ago, but then again we do live in a capitalist society.

(Ya gotta love capitalism.)

[Currie]

I mentioned it on the first page.. but the hull flexes A LOT. any firm bulkhead in this area will be a location for stress point . Not good of you are rafted, and have a fender between you and the boat (or dock, etc)..and a killer wake comes by

These are tough boats, but after being woken up at 5am, rafted with another Mac, and having a Maine lobster boat pass leaving a wake of insane magnatude. I could see the hull flex where the fender was, a good 8-10 inches into the boat.. I had to brace myself on the starboard bunk pressing my back onto the hull to minimize the deflection. I was STUNNED how much they flexed without breaking! I was CERTAIN it would crack the gelcoat/fiberglass..but it did not!

Not being a buzz kill, but I would be super careful in creating a bulkhead in an apparent engineered flex area.

Paul

Hi Paul,

Not a buzz kill at all, in fact, I changed the design based on your original comments (read above). Rather than an edge of 1/2" plywood contacting the hull/liner, the bulkhead will "run back" about 3" and stay roughly 1/2" away from the hull. This 3" X 1/2" space will run from top to bottom and be filled with 2.5" X 1/2" styrofoam (the live, spongy kind). The styrofoam will be covered with mildew-resistant cloth or felt to stop squeaking and the exposed half inch along the edge will be covered with decorate rope, tucked in. That really should do the trick. Thanks again for pointing it out. I agree totally.

~Bob

[Terry]

Not being a buzz kill, but I would be super careful in creating a bulkhead in an apparent engineered flex area.
Paul

Curious as to just how much flex is required in that area. The traveller is located in that stress point, as is the framework of the companionway, not to mention the support the companionway ladder provides. Then there is the overlap where the top cabin liners join there too, and the seats also end there with reinforcement, and that reinforcement extends port to starboard across the cabin floor. Seems to me that would be the least flexible ridge area of the boat lenght excluding bow and stern. I see Bob has a work around for it but is it really that necessary?
One more point; is the flex really engineered or is it just a byproduct of economic manufacturing?

[Currie]

Yeah structurally it's pretty stiff there, although flexible in the middle of the upper hull panel itself - mostly above the chine. I'd crap if I actually witnessed it bump in 10" I'm with Paul on not running edges against it if it does get bumped, so I'm softening it.

That's more than Roger did, however - (on my '04 boat), the galley and head bulkheads just butt the plywood edge right up to the hull. There's less flex there but it would strain if the hull was compressed from the outside. Better safe than sorry on the rear bulkhead, I guess. It won't allow 10" of flex, but will better distrubute the "bump".

~Bob

[Terry]

Hi Paul,
Not a buzz kill at all, in fact, I changed the design based on your original comments (read above). Rather than an edge of 1/2" plywood contacting the hull/liner, the bulkhead will "run back" about 3" and stay roughly 1/2" away from the hull. This 3" X 1/2" space will run from top to bottom and be filled with 2.5" X 1/2" styrofoam (the live, spongy kind). The styrofoam will be covered with mildew-resistant cloth or felt to stop squeaking and the exposed half inch along the edge will be covered with decorate rope, tucked in. That really should do the trick. Thanks again for pointing it out. I agree totally.
~Bob

Ok Bob, so what is going to support the edges that would normally butt up against the hull above the chines? I can see drilling in to the upper beige liner for some support as that overhangs enough to put a screw through. I hang "S' hooks and trays under it to hang coats from and put stuff in so I know there is a good space under it, even put one of those over the door plastic coat hangers under it but pulled the over the door parts off and put them on backwards so that it would function.(I have had my hands scraped trying to put hooks under it, I even installed a grab handle under it just across from the head to keep my balance going forward). Still, you may want to have a brace of sorts glued vertically on the hull to keep your new wall from flexing back and forth, you never know who might put a pillow behind them then lean against it while reading a magazine from those cool racks you have pictured. I guess I am more concerned about support than flex. I have never experienced what Paul has in any of the raft ups I was tied to.

[Paul S]

my last comment did happen, we were on a mooring, rafted, and the boats bounced together ruthlessly.. you could see the deflection..if it wasnt 8 inch..it was sure close..

as long as there is some flex in the bulkhead design, you should be ok.

you can see inside the liner with the holes on either side, apparently is there for flexing. One of the dealers boats we were on (in FLA) had numerous cracks in that liner flex section (above the girls head in this pic) http://www.macgregor26.com/interior_and ... _large.jpg No doubt if it was ridgid there, it would certainly crack the hull itself.

I just wanted to point out the flexing as a public service annoucement

[Currie]

Ok Bob, so what is going to support the edges that would normally butt up against the hull above the chines? I can see drilling in to the upper beige liner for some support as that overhangs enough to put a screw through. I hang "S' hooks and trays under it to hang coats from and put stuff in so I know there is a good space under it, even put one of those over the door plastic coat hangers under it but pulled the over the door parts off and put them on backwards so that it would function.(I have had my hands scraped trying to put hooks under it, I even installed a grab handle under it just across from the head to keep my balance going forward). Still, you may want to have a brace of sorts glued vertically on the hull to keep your new wall from flexing back and forth, you never know who might put a pillow behind them then lean against it while reading a magazine from those cool racks you have pictured. I guess I am more concerned about support than flex. I have never experienced what Paul has in any of the raft ups I was tied to.

Hi Terry, the bulkhead unit will be vertically rigid (even with the mantle shelf), and secured only on the top and bottom (nothing along hull wall). I'll visit the boat this weekend and make my detail plans. Stay tuned

~Bob

[Québec 1]

Buying a blue 2003 26M next week. Am wondering if I can get the porthole wood trims like in the 05-8 models. Am ready to take on that rear berth mod. The first thing to do is the hinged ladder . Seems to be a good mod(take the steps off the actual ramp, fasten them on a ramp made of the correct size pvc pipe which has been sliced so that it accepts to snap on to the existing railing. The steps could also have bolts which slide into the existing rail holes for solidity. Already dreaming its great.

[Terry]

The '03 & '04 models are the ones that are most conducive for Bobs' project. As for the ladder, it supports the cockpit so be careful what you do with it. I was thinking to replace it with a set of brackets. If you look to the right of the letter 'P' on your keyboard you will see a couple sets of brackets on the adjacent keys. Ignore the curvey ones and check the square ones, I think a set of SS brackets of that shape would provide a larger access door and support the cockpit, while making use of the existing bolts and holes, then you can put whatever swing ladder you want there.
Forget the wood trim windows, someone else looked into it and discovered it had to be done at the factory level. You could fabricate your own version but I found that the curtains made a wood frame redundant as you would never see the frames behind the curtains anyway.

[Québec 1]

I agree with your suggestion which would widden the access to the rear berth but I do not really want to change the bars that are already there (the simpler the better and don't want to play with structural elements)would it still be wide enough? To bad about the wood window frames. I will look into a window molding which has curtains incorporated in them.

[Currie]

Some progress....



Lot's of trim, doors, etc. to add - not to mention the doorway (the part with the strength).

Cheers,

~Bob