Lofting the Brewer catboat

[Jim Ledger]

Oh, you want a "nice" lid?

That is a lot of conflicting curves over a small space, good thing you have a built-in moaning spot. This will be fun watch.

And I'm looking forward to building it.

Cold mold it, Fairy did it with the Atlanta, although it is suggested that they used the Fairy Duckling dingy. That way no beams are required.
The hatch carlings can go on top and double as a grab rail forward.

Perhaps, next time, Nick. This ill be the now-traditional double ply on deck beams with a couple of layers of glass cloth.

Good to see you back working on the boat!
That cabin top is much more than I could handle but I've no doubt you
will show us the way.

When I find the way, Rich, I'll certainly show it.

Our boat had a complex cabin top shape. Here's how Jespersen's approached it:

Laminated beams over temporary molds.

Cedar beveled tongue and groove planking

Outside view of planking

A layer of glass, followed by blocking for hardware and closed cell foam.

Two layers of 6mm ply, vacuum bagged over the foam/blocking.

Thanks for the instructive photos, Dave. There's good stuff there

Probably did not need the laminated beams, they were of tiny scantlings. Unless they were there to secure the first layer of the plank?

You can't bend plywood over thin air...I've tried.

That’s a pretty good size panel to stiffen.
Is it maybe ten feet long and ten feet wide? Can it be supported on centerline from centerboard trunk?
The composites guy in the port lazarette of my brain is muttering about >1”foam sandwich, but I know that’s not it.
I can hardly wait.

Ten wide by eleven long, Jim. There's the possibility of a post off the CB trunk, Jim, and there will by a couple of sets of knees between the roof and cabin side.


Here's the first of the deck beams. The shape was derived from two measurements, the width and the height on the centerline. The curve was generated using the two stick method, which I will explain in a future post if anybody's curious.

I used six laminations in this beam, but changed the rest to seven laminations in order to reduce springback. The cross section dimensions are 1 3/4" by 2 1/4"






Here it is sitting on the boat...

[hawkeye54]

Jim, I was going to (extreme tongue-in-cheek) suggest a clear cabin top, like I had on an old 1950's Ford Crown Victoria I once owned, would be great for watch the stars on a clear night - but the weight would make it a bear to keep the shiny side up ( ) I am watching with interest as you build it.



Rick

[Breakaway]

Just checking in. Good to see you at it, Jim.

Kevin


Sent from my iPhone using Tapatalk Pro

[Jim Ledger]

Just checking in. Good to see you at it, Jim.

Kevin

Thanks, Kevin. Since my last post I've had a bit of surgery on my back Thanks to that and some excellent physical therapy I'm feeling better than I have in quite some time. The pain has gone.

Jim, I was going to (extreme tongue-in-cheek) suggest a clear cabin top, like I had on an old 1950's Ford Crown Victoria I once owned, would be great for watch the stars on a clear night - but the weight would make it a bear to keep the shiny side up ( ) I am watching with interest as you build it.

Rick

You know, Rick, what happens to those clear materials, they look great when new but after a couple of years they get scratched up and cloudy. Where then, are the oooh's and aaah's?


I've taken a bit of a leap. I laminated up eleven deck beams, each one different, using scant information, in the hope that all would end well. Late yesterday I roughly positioned them on the cabin sides. Something's up with the third one aft but the rest look fairly reasonable. The top of the cabin sides need to be trimmed fair and beveled, which should help to bring things into line. What I do know now that I didn't before is the precise bevel for the top of the sides

So that now, the entire top of the cabin sides can be faired in, from the bulkhead forward. Having done that, the line can be faired into the cockpit sides, and having made the necessary deductions the cockpit sides can also be cut. The cockpit sides get cut level across the top because there's a cap that will fit on top.

If anyone's curious, the deck beam curves were obtained by the two stick method, as opposed to the semicircle-divided-into-sections method. The problem with the latter, in this case, is that the ends seem to get flattened. The two stick method ends up with a plumper-looking shape, which looks right here.

Cheers, y'all

Jim

[willin woodworks]

Good to have you back Jim, glad to hear youre on the mend.

Looking forward to more posts....

JRM

[Jim Ledger]

Looking forward to more posts....

JRM

Thanks, Willin. Here's one...


You're looking at one of the notches that have been cut in the top of the cabin side at the location of each deck beam. This cut represents the minimum amount of material that will need to be removed to provide a landing for the roof plywood. When the beams are removed we are left with a row of notches which progress in depth as we move aft. A batten clamped on the outside of the cabin side, lined up with the bottoms of the cuts will delineate the amount of material to be removed between the cuts. However, as the top of the cabin side is not quite fair the batten will only be able to intersect the lowest cuts. By removing the waste material to the battened line we will end up with a fair line. The notches which don't touch the line can be deepened to the line being careful to preserve the angle.

You can see the difficulty involved in fairing up the cabin top without knowing the changing angles involved. I suppose the whole thing could be lofted and the bevels picked up in that way, but that's a lot of work and would be difficult to do accurately. With little wood to spare the direct measurement from the deck beams themselves offers a solution that can be relied upon and then cut with confidence.



Jim

[Larks]

That sounds like a task that gets more challenging as you move forward to the curve of the cabin Jim, even though the cut is shallower..?? But I’m assuming that once you have the angle for the top you can replicate the same angle for the deck beam cutouts? Which, by the way, I’m still interested to see how you execute.

[Jim Ledger]

That sounds like a task that gets more challenging as you move forward to the curve of the cabin Jim, even though the cut is shallower..?? But I’m assuming that once you have the angle for the top you can replicate the same angle for the deck beam cutouts? Which, by the way, I’m still interested to see how you execute.

Greg, you're correct, the front of the cabin is more difficult to properly line off, due to flat bevel and few reliable reference points. The front of the cabin side will be treated separately because of the curve. The batten I'm using for the sides won't go around the really curved parts, fore and aft. There will have to be a more flexible batten to go around the tight curves, and this thin batten will have to blend into the side line.

Here is the side batten being unclamped. The line is the top of the masking tape. You can see here how the beveled notches get shallower as you move forward, due to the shape of the beams. The next step is to use a slick and plane to remove the waste between the notches...

[hawkeye54]

It's coming together nicely, Jim !




Rick

[Peerie Maa]

Greg, you're correct, the front of the cabin is more difficult to properly line off, due to flat bevel and few reliable reference points. The front of the cabin side will be treated separately because of the curve. The batten I'm using for the sides won't go around the really curved parts, fore and aft. There will have to be a more flexible batten to go around the tight curves, and this thin batten will have to blend into the side line.

Here is the side batten being unclamped. The line is the top of the masking tape. You can see here how the beveled notches get shallower as you move forward, due to the shape of the beams. The next step is to use a slick and plane to remove the waste between the notches...

Jim, I would be tempted to leave the ford end until the other beams are fitted. Then you could use a straight edge to project the curve forward to set the bevel around the front. There is no round down to the coach roof, so that should work.

[Jim Ledger]

Jim, I would be tempted to leave the ford end until the other beams are fitted. Then you could use a straight edge to project the curve forward to set the bevel around the front. There is no round down to the coach roof, so that should work.

Right you are, Nick. The thing I'd like to avoid is having the forward end of the roof droop down to meet the cabin front. A batten laid across the deck beams will make a good guide.

Here is the cabin sides being taken down between the notches...

[Steamboat]

Jim, Your boat just keeps getting more beautify with every post. I'll just keep viewing and sublimating my boat building urges.

[stromborg]

Jim, Your boat just keeps getting more beautify with every post. I'll just keep viewing and sublimating my boat building urges.

I'll agree with Steamboat on the first sentence. The second? Not so much, it inspires me want to go out a build another boat in my shop. There are a few "honey-do" and "Steve-do" projects left (including enlarging the shop for Next Boat) but watching this catboat come along helps me keep my nose to the grindstone.

[Jim Ledger]

Jim, Your boat just keeps getting more beautify with every post. I'll just keep viewing and sublimating my boat building urges.

Thanks, Steamboat. I hear that making models helps with that sublimating thing and one of these days I'm going to try it out for myself.

I'll agree with Steamboat on the first sentence. The second? Not so much, it inspires me want to go out a build another boat in my shop. There are a few "honey-do" and "Steve-do" projects left (including enlarging the shop for Next Boat) but watching this catboat come along helps me keep my nose to the grindstone.

Thanks, Steve. Might I suggest getting hold of some plans to moon over? That way you know just how big to make that shop.

Cheers,

Jim

[stromborg]

Thanks, Steamboat. I hear that making models helps with that sublimating thing and one of these days I'm going to try it out for myself.




Thanks, Steve. Might I suggest getting hold of some plans to moon over? That way you know just how big to make that shop.

Cheers,

Jim

The plans are hanging on the wall in my bedroom. Last thing I see as I turn off the light...

[Jim Ledger]

The plans are hanging on the wall in my bedroom. Last thing I see as I turn off the light...

Now I have to know...what's the design?

The light looked nice yesterday, shining through the poly, so I snapped this one. The port side this time, batten clamped on and ready to mark the line.

[stromborg]

Now I have to know...what's the design?

I've been thinking about this boat for a long time, picking up parts here and there along with learning ancillary skills like bronze casting. My current shop is only 23' deep, the mental exercise of how to lengthen it enough to build a 24' boat has been done now I just need to do it. I'm about 3 years out from hanging up my uniform for the last time, I'd like to start lofting in 2.

[Rich Jones]

^ Not to begin a thread drift but....
Start lofting now. Build your station molds.
Start building components. Make some sawdust!
The ANNIE design is one of the most beautiful boats I've ever seen.

[hawkeye54]

Not drifting, but - go back to page 1 / post 1 of this thread for an idea on how to get started . .

( and please disregard my signature )

[Michael_Owen]

Ohh. Annie. A photo of her sits on my desktop. Love it.

Quietly following along, Jim. Thanks as always for taking the time to share your project with us.

Mike

[willin woodworks]

^ Not to begin a thread drift but....
Start lofting now. Build your station molds.
Start building components. Make some sawdust!
The ANNIE design is one of the most beautiful boats I've ever seen.

Just so...start lofting and building molds. When you're ready to build you're already on the way. Laying down the lines is like building the boat in your mind...

And what a damn pretty boat!

[Geftb]

Good to see you back at it Jim! Always a pleasure to tag along.
Cheers
Steve

[jpatrick]

Jim, you continue to do great work!

Those of you urging Stromborg to get going must have missed the part about him having a 23' shop and plans for a 24' boat. Which end do you think he might ignore when lofting?

Jeff

[Peerie Maa]

Jim, you continue to do great work!

Those of you urging Stromborg to get going must have missed the part about him having a 23' shop and plans for a 24' boat. Which end do you think he might ignore when lofting?

Jeff

Lofting is not a problem, you just use more colours for the lines and overlap 3 or 5 stations in the middle of the boat.

An extra 2 foot on the shop only reqires a "Portch" built around the door opening. I have a photo of just such an extension on my PC at home.

[Jim Ledger]

I've been thinking about this boat for a long time, picking up parts here and there along with learning ancillary skills like bronze casting. My current shop is only 23' deep, the mental exercise of how to lengthen it enough to build a 24' boat has been done now I just need to do it. I'm about 3 years out from hanging up my uniform for the last time, I'd like to start lofting in 2.

Thank you all for the words of encouragement.



Steve, I've admired Annie ever since she was a cover girl on a WoodenBoat issue. I can't remember which issue, it was a while back, but you doubtless know the one I mean. I've been thinking of a few enjoyable tasks that might be worked on before the actual beginning of construction. Here's a few...

Loft at a quarter scale, just for the fun of it.

Build a model, it doesn't have to be a complete thing. Even a model of the backbone, transom and a midship station gives you something to moon over.

Talk to some sawyers. You live in the land of Doug Fir and Alaskan Yellow Cedar. Make some lists.

Get some saved searches going on Ebay. Things like bronze screws and bolts, nav lights and other specific pieces of hardware. Put this guy in your favorite folder...https://www.ebay.com/str/rags4jc. The hardware is out there, it's probably not cheap, but at least you can find it.

Get some wood piled up if you can, let it sit under cover and acclimate. There's noting beats a pile of lumber to get you going.

And so on. Good luck and I look forward to your thread. That's a great boat!




Here we have the deck beam that goes alongside the aft bulkhead. A couple of pockets have been chiseled into the cabin sides to contain the ends of the beams. The pockets go through the sides to the outer layer of Mahogany. The beam is slightly high, as they all will be. Once they're all sitting in pockets then they will lowered down as a group. It's a timid approach, sure, but I'm feeling my way along here. I can alwys cut away more wood...putting it back is more difficult.

cheers,

Jim

[Jim Ledger]

So far, so good.

I was in no way sure how this would work out. I had a plan to glue extra laminations on the top of the deck beams and recut the undersides, if needed. Five beams in and there's no need for that yet.

The real test lies ahead, where the cabin sides come together rapidly, the sheer increases and the deck beam camber decreases.

However, now that these beams are in I've been able to cut down the top of the bulkheads very close to their final height, which makes the whole boat look better.

[Rich Jones]

A symphony of beautiful curves!
Many parts coming together to create a masterpiece.

[chas]

Hi Jim, still lurking and watching your marvellous build! After looking at multiple pics I'm still unsure if cabinsides are vertical allround. Giving the strength of those laminations I'm assuming the beam ends would be plumb cut regardless? Mostly I'm wondering whether the seat cuts follow the line of camber or if you have cut them horizontal to reduce any potential sheer stresses on that joint. Perhaps you're method for afixing these joints eliminates any consideration in this regard?
Great to hear your back issues are being resolved! All the best going forward. / Jim

[Andrew Donald]

Love those cabin beams Jim. Having done mine recently- (well a couple of years ago!) I can appreciate the difficulty. must say I cheated and used a Carlin to sit em on!

I’m wondering, the ends look like they finish a veneers thickness in from the outside, how will the outside be treated to avoid mirroring of beams on outer or is this accounted for?

Watching and admiring from down ere.

[Jim Ledger]

A symphony of beautiful curves!
Many parts coming together to create a masterpiece.

Thanks, Rich, it's very enjoyable cutting away the waste of the bulkheads and cabin sides, cutting close to the final line.

Hi Jim, still lurking and watching your marvelous build! After looking at multiple pics I'm still unsure if cabinsides are vertical allround. Giving the strength of those laminations I'm assuming the beam ends would be plumb cut regardless? Mostly I'm wondering whether the seat cuts follow the line of camber or if you have cut them horizontal to reduce any potential sheer stresses on that joint. Perhaps you're method for afixing these joints eliminates any consideration in this regard?
Great to hear your back issues are being resolved! All the best going forward. / Jim

Jim, the cabin sides cant inward along their length, which creates problems when notching in the ends of the deck beams. The seat cuts on the ends of the beams are planed horizontal, in order to sit squarely in the pockets. The beams will eventually be glued to the pockets in the cabin sides with thickened epoxy.

Love those cabin beams Jim. Having done mine recently- (well a couple of years ago!) I can appreciate the difficulty. must say I cheated and used a Carlin to sit em on!

I’m wondering, the ends look like they finish a veneers thickness in from the outside, how will the outside be treated to avoid mirroring of beams on outer or is this accounted for?

Watching and admiring from down ere.

Andrew, the outer veneer of the cabin sides is hard mahogany a quarter inch thick. There will be two layers of six ounce cloth on the cabin top which will roll down onto the cabin sides, reinforcing the area where the pockets have been cut. The edge of the glass will then be covered by a coved-out half round molding. This will cover much of the area under which the beam ends reside, so I don't expect much in the way of the pockets telegraphing through to the outside.

[chas]

Thanks for your explanation Jim. Looking forward to the continuation of this process. / Jim

[Andrew Donald]

Thanks for your reply Jim. I always admire your individual responses to everyone that chips in, even after all this time. Your stamina in producing what must rate as the most valued thread is magnificent.

[Jim Ledger]

Thanks, Jim, Andrew for the words of encouragement.

Here's a photo of the deck beam sockets that might be of interest to those few who wish to spend their time in such foolishness. For the rest, please bear with me a while longer.

The first point of interest is the painters tape. Due to the angles and geometry involved it is quite impossible to establish the bottom cut. Although the deck beam is cut square on the bottom, due to the inward cant of the side and the inward curve as we move forward, the bottom cut is anything but level. The bottom cut must therefore be snuck up upon, the socket gradually deepened until the top of the beam sits at the right height. The painters tape gives a good, sharp edge to cut to, and it can be set up by eye. Here the beam needs to drop about an eight of an inch, two, three mm, or so.

The second point of interest if the radius on the underside of the beams. Here the radius is roughed out, which makes the beam more pleasant to handle. Once fitted, radius is marked and cut to within an inch and a half of the side. Then the radius will be diminished to nothing at the cabin side, by hand, using a spokeshave. This same detail will also be used where fore and aft framing members intersect the beams, such as the hatch opening and skylight.

It's all I've got so far, I wish there were more.

Jim

[amish rob]

Baby steps, Yo. Baby steps. Keep grinding, you’re starting to get close to the end, man.

[Peerie Maa]

The second point of interest if the radius on the underside of the beams. Here the radius is roughed out, which makes the beam more pleasant to handle. Once fitted, radius is marked and cut to within an inch and a half of the side. Then the radius will be diminished to nothing at the cabin side, by hand, using a spokeshave. This same detail will also be used where fore and aft framing members intersect the beams, such as the hatch opening and skylight.

It's all I've got so far, I wish there were more.

Jim

You are in charge Jim, but for me, I would leave the end square with a stopped radius as now, but extended further out as aesthetically pleasing.
Running it out to nothing is nether here nor there in my eyes. Episode 73 of Tally Ho's build shows off the finished effect.