Lofting the Brewer catboat

[Jim Ledger]

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

Two more yeas, Rob, two more years.

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.

What is this Tally Ho of which you speak, Nick?

As for the stopped radius as opposed to the diminished variety, you're probably right, the stopped version is the more definitive detail.


Jim

[Larks]

I don’t know if it’d be of any help to you Jim (noting that my joinery isn’t anywhere near as precise as yours) but I tried both options for the radius and ended up taking it all the way out and this is how it came out - noting that my joins will probably be somewhat different as I was kinda making it up as I went.......



[IMG]IMG_3817 by Greg Larkin, on Flickr[/IMG]

[IMG]IMG_3818 by Greg Larkin, on Flickr[/IMG]

[IMG]IMG_3820 by Greg Larkin, on Flickr[/IMG]

[IMG]IMG_3931 by Greg Larkin, on Flickr[/IMG]

[IMG]IMG_3957 by Greg Larkin, on Flickr[/IMG]

[IMG]IMG_3985 by Greg Larkin, on Flickr[/IMG]

[Hwyl]

It looks precise to me Greg.

[WX]

I don’t know if it’d be of any help to you Jim (noting that my joinery isn’t anywhere near as precise as yours) but I tried both options for the radius and ended up taking it all the way out and this is how it came out - noting that my joins will probably be somewhat different as I was kinda making it up as I went.......



[IMG]

I'm not showing you closeups of mine.

[Jim Ledger]

I don’t know if it’d be of any help to you Jim (noting that my joinery isn’t anywhere near as precise as yours) but I tried both options for the radius and ended up taking it all the way out and this is how it came out - noting that my joins will probably be somewhat different as I was kinda making it up as I went.......

That's a fine piece of work, Greg. I take your point about running the deck beam radius all the way to the cabin sides. It looks good in your case, but as I've already cut square pockets in my cabin sides it's not possible for me. I'll have to be satisfied with the stopped radius.

One of the photos puzzles me where the deck beams seem to be sitting proud of the cabin side top edge, but i a subsequent photo all is planed flush as you would expect.

I see you're using some blocking between the beams . Is this to provide a wider edge for the cabin top to rest upon? I've been considering something similar, but due to the curves involved the job would be complicated and time consuming. I'm not ure that I would really need it.

Well done all around.



A few posts back Nick mentioned trimming the forward part of the cabin side in conjunction with the deck beams. This photo shows that operation halfway through. The center point is at the correct height, but as the sides curve back there's a section that needs trimming down. There's a sort of "moose shoulder" thing going on. It was worse but a lot of the material has already been planed off. It's apparent here the relationship between the deck crown and the top of the cabin sides. A chalked straight edge, held parallel to the boat centerline and rubbed on top of the beams and sides shows up the high spots that need to be planed off. It's a pleasant job as the line just keeps getting sweeter the more is planed off.


Jim

[Larks]

[QUOTE=Jim Ledger;6815046
One of the photos puzzles me where the deck beams seem to be sitting proud of the cabin side top edge, but i a subsequent photo all is planed flush as you would expect.

I see you're using some blocking between the beams . Is this to provide a wider edge for the cabin top to rest upon? I've been considering something similar, but due to the curves involved the job would be complicated and time consuming. I'm not ure that I would really need it.

[/QUOTE]

Yes you’ve found me out Jim - I’m missing a photo of how I changed my mind mid stream: I was trying to maximise every mm of head height and I originally had the idea that I’d fit the blocking pieces between the deck beams so that their inside edge was level with the beam, fair the outside edge down to the deck beams and then fill the small wedge left on top of the cabin side with epoxy.

Then I kinda felt that was the lazy way of doing it and potentially also the messier way of doing it so what I don’t have a photo of was when I subsequently decided to drop the deck beams down so that they sat level with the inside edge of the cabin sides, rather than the outside edge, and then faired the outside edge of the cabin sides down to them.

In truth it ended up being a bit of a compromise as I fought the loss of every mm of head height and there is still a small amount of epoxy along that top edge to fair it properly but the blocking pieces hide any of those sins and I prefer the finish with them internally, particularly as I think they'll better balance the trim piece/grab rail that I have yet to fit along the inside of the cabin side carling.......(which will/should be a whole lot slimmer and more refined than that piece of ply holding the mock up port hole on the starboard side of the bottom pic).


I’ll be really interested to see that last pic of yours side by side with the finished trim. At the moment it looks really sweet to me while also presenting a sort of a sense of purpose in appearance - if that makes sense - your “moose shoulder” I guess. Though in the pic I can’t really see how well the deck runs into it

[Breakaway]

Looking good, Jim.
Thanks for sharing!

Kevin


Sent from my iPhone using Tapatalk Pro

[Jim Ledger]

Looking good, Jim.
Thanks for sharing!

Kevin

Thanks for the encouragement, Kevin.

I’ll be really interested to see that last pic of yours side by side with the finished trim. At the moment it looks really sweet to me while also presenting a sort of a sense of purpose in appearance - if that makes sense - your “moose shoulder” I guess. Though in the pic I can’t really see how well the deck runs into it

Thanks for the info about your deck beams, Greg.


To your question, I always try to take a few pictures, from several angles, of something that I need to fair up. The camera often picks up unfairness not apparent to the eye. And sometimes it doesn't. That bow-on photo of the cabin top looked pretty good until a batten was clamped on, and then a couple of humps showed up.


So, having established the height of the cabin itself, it's now possible to extend the line back onto the cockpit coaming. To get a nice fair line that runs continuously fore and aft, a batten was clamped to the finished part of the cabin sides and allowed to run aft.

One important tip when working with battens is to support the ends of the batten where it runs off on the ends, put a stick under it, bend in extra curve, because if you don't the ends of the run will be flatter than they should and will lack life.



So, here we are with some blue tape making the line more visible. The top edge of the tape is the finished height of the coaming. From this height needs to be deducted the thickness of the coaming, minus the height of the groove in the underside of the coaming.

But it's that top line that needs study, that's what you will mainly see.

A word about the coaming might be in order, to help visualize a most important intersection. Imagine a half round molding that goes all the way around the cabin top. It's top edge will line up with the top edge of the sides as we see them here. The thickness of the deck, with it's radiused edge, will be above this point. The molding, where it passes from the cabin side and onto the cockpit coaming, will be notched into the coaming edge and fastened, maybe an overlap of four to six inches. The coaming edge will continue the cross section of the molding, seeking to make a seamless transition.

Everything works back from that.

[stromborg]

That is delightfully swoopy

[Jim Ledger]

That is delightfully swoopy

Most delightful, I can assure you, Steve.


There's been a small gathering of hardware on the forward deck for some time now, coupla cleats, a pair of pad eyes, two ventilators, fairleads, and one small porthole. They get carefully positioned from time to time and then quickly devolve into the usual heap. Taken together they represent a considerable lump of commitment, considering all the drilling required, even after all the decisions have been made.

There is one piece missing, however, a mast boot fitting. Many's the night sleep has overtaken me while pondering the form it should take. Many. Until the other day. I was wasting time idling through Facebook and a picture appeared in the Catboat Association Lounge. This picture was of the venerable catboat Pinkletink's forward deck, and there was a sweet little collar made of sheet bronze. Realizing my luck I was able to immediately stop thinking completely, no point now, the work is done, nothing left to figure out. Sweet nothing...ahhhhh.

So, it was with an empty head that I rummaged through the box of bronze scraps, and I came up with a piece that, cut just so, would yield the half-dozen or so pieces with which to make the bottom flange.

[willin woodworks]

Now that's a compass!! Or pencil divider depending on your preference...

[Jim Ledger]

Now that's a compass!! Or pencil divider depending on your preference...

It's all those things, willin, but I use it mainly as a scriber. I worked with a guy who had one just like it and he never got tired of telling me just how great a scriber it was. One lucky day, several years later I came upon that one in an estate sale, that and a leg vise.


Here's the welding-up of the ring in progress...

[Jim Ledger]

Here's the flange, drilled and countersunk for a dozen screws...





The forward deck, drilled for fastening. Anywhere a screw has to pass through the deck plywood the plywood gets bored out for an epoxy plug. The plug gets drilled out to the shank diameter while the point of the screw threads into the Locust king plank beneath the plywood. All to keep water away from the plywood edge.

[Jim Ledger]

In order to bend some sort bronze cylinder I made a cylindrical form. It's a stack of pieces of MDF glued up and then turned to a quarter inch less than the required diameter. Gluing on a skin of eighth inch plywood put the diameter back to within tolerances. Looking here you can see the cylinder propped up on the flange. Wrapped around the cylinder is another piece of ply, this one is the pattern. There's a line just been scribed all the way around the pattern, this line's the cut to meet the deck flange.











Here's the pattern, all unwrapped, and underneath two pieces of eighth inch bronze plate. These plates get welded together at the wide end and then get bent around the form.

[Larks]

I’m pretty sure that I’ve asked you this before Jim when I was making up some bronze floors (or maybe thought to ask and didn’t?), either way I’ve forgotten the answer - when you say “welded”......??? How are you welding the bronze in this case?

[Breakaway]

Hi, Jim!

Thanks for sharing.


Kevin


Sent from my iPhone using Tapatalk Pro

[Jim Ledger]

I’m pretty sure that I’ve asked you this before Jim when I was making up some bronze floors (or maybe thought to ask and didn’t?), either way I’ve forgotten the answer - when you say “welded”......??? How are you welding the bronze in this case?

I'm using a TIG welder, Greg. It's a Miller Synchrowave 250, water cooled, using Argon gas as a shield. It's good up to about three sixteenths thickness, quarter inch is pushing it but doable.

Hi, Jim!

Thanks for sharing.


Kevin

You're welcome, Kevin.


Here's the piece itself, set up on the bow, with an arbitrary scribe line marked to trim off the top. The cylinder has been welded to the flange on the inside, a continuous bead all around.

[Rich Jones]

It's a thing of beauty but can you explain to this easily befuddled old guy how the mast boot fitting is used?
How are the mast wedges inserted and how is the mast boot attached to mast and boot fitting?

[stromborg]

I'm wondering how you got such a clean bend in the 1/8" bronze! A TIG welder is on my list of things I'd like to acquire in the next year or so.

[Jim Ledger]

It's a thing of beauty but can you explain to this easily befuddled old guy how the mast boot fitting is used?
How are the mast wedges inserted and how is the mast boot attached to mast and boot fitting?

Sure, Rich. In order to prevent rain and spray from going down the mast hole, a fabric tube will be lashed onto the mast and the mast boot fitting, for lack of a better term. The tube will actually be hand sewn shut before being lashed on. Some effort will be made to account for the diameters of the mast and fitting in order to bring forth a shapely boot with a minimum of wrinkles.

The diameter of the fitting is larger than the wedges, so there's clearance there. Little attention need be paid to the tops of the wedges, yanno, keeping them in a line, because they'll be covered by the boot.


Here's a couple of shots taken at the moment that the fitting looks just good enough to try out on the boat, and I promise myself to spend another couple of hours polishing later on.






A ring made of 5/16" diameter bronze rod was bent and welded along the top edge. This edge will hold the lashing. For a lashing I'm thinking about a half dozen turns completely around and tied tight. You can paint the whole thing, boot, lashings and all.

[WX]

For Redwing I made mine out of rings of plywood and glued it to the mast. The mast looked like a giant jousting stick, and it worked perfectly. Rot was a problem after a few years though.
Yours is very classy.

[Larks]

I'm using a TIG welder, Greg. It's a Miller Synchrowave 250, water cooled, using Argon gas as a shield. It's good up to about three sixteenths thickness, quarter inch is pushing it but doable.





You're welcome, Kevin.


Here's the piece itself, set up on the bow, with an arbitrary scribe line marked to trim off the top. The cylinder has been welded to the flange on the inside, a continuous bead all around.

Thanks Jim, do you have any trouble getting filler rod to match the bronze that you’re using for the fitting?

[Jim Ledger]

I'm wondering how you got such a clean bend in the 1/8" bronze! A TIG welder is on my list of things I'd like to acquire in the next year or so.

I did have that turned cylinder to bend the piece around, and that helped. I was able to use a band clamp to put in a lot of the bens. In the end I laid the sheet in an open vise and tapped it with a rubber mallet. Small hits and a lot of checking against the form. The ends need bending more than the middle.

Go for the tig machine, don't put it off.

For Redwing I made mine out of rings of plywood and glued it to the mast. The mast looked like a giant jousting stick, and it worked perfectly. Rot was a problem after a few years though.
Yours is very classy.

Thanks, Gary, I remember that mast.

Thanks Jim, do you have any trouble getting filler rod to match the bronze that you’re using for the fitting?

No problem at all, Greg. Silicon bronze is a very common filler material and can even be used to weld mild steel.

[Rigadog]

Is that walnut in the interior?

[Jim Ledger]

Is that walnut in the interior?

The interior of the cabin sides are mahogany, but it’s a dark piece.

Jim

[Dhermann]

Jim - Can you/would you please try and get a picture of the mast boot from inside the cabin?

[Jim Ledger]

Jim - Can you/would you please try and get a picture of the mast boot from inside the cabin?

Looking up through the mast hole, do you mean? There wouldn't be much to see as the boot is larger than the hole itself.


The cockpit coaming has been cut down to it's finished height here. Everything looks much more trim with the cabin sides and the bulkheads cut down to height. The coaming will be higher by three quarters of an inch once the cap goes on, but the line will be the same.

This is the first I'm able to get this shot, due to changing the lighting from the old florescents to LED's. Much room was freed over the boat and the lighting is much improved.

Jim

[Rich Jones]

Looking great!

[WX]

I've run out of superlatives Jim.

[Mike1902]

A lovely blend of curves there, Jim.
I have been perusing some of your past posts in regard to the cockpit coamings as I am just about to start mine.
Though the dinghy coamings are on a way smaller scale, when sheer, camber and splay are combined it's good to see how others have tackled the situation and I thank you.
Fantastic work, Jim.

Cheers,
Mike.

[hawkeye54]

This is the first I'm able to get this shot, due to changing the lighting from the old florescents to LED's. Much room was freed over the boat and the lighting is much improved.

Jim

No more flickering flourescents, and a modest reduction in the electric bill, to boot . . . .