Longitudinal sheer stringer in an Indian

[Jlaup]

I've put this is Design/Plans because it is a design alteration question.
I am about to fit the sheer strakes on my boat. I have built the boat in glued ply with 3/8th sapele rather than the 5/8 pine clinker that Alden specified.
http://farm5.static.flickr.com/4013/4335971160_d8c24a5d02.jpg
I was thinking I would add a 3/8" longitudinal stringer at the sheer to give me some more nailing/screwing surface for the deck and to add stiffness. I would let it in to the sawn frames, transom, and stem. I would probably use fir.
I have only one concern. The plans specify 7/8" sided by 3/8" moulded bent frames between the sawn frames. The stringer will make these harder to fit.
I'm pretty sure the stringer is a good idea. As for the bent frames, the boat seems mighty stiff as is. Do I need them?
If John W. or Roger L. is on, it would be great to hear their thoughts.
But all input is very gratefully accepted.
Thanks,
John

[Thorne]

Are you describing an inwale? If not, why not consider one for this function?

[mmd]

No, you probably don't need the bent-in frames. But then, you probably don't need the 'stringer', either.

[Thad]

There should be a clamp inside the frames to support the sheer and the deck beams and half beams. What MMD said.

[wizbang 13]

maybe use thicker ply for the sheer strake. " Let into "the sawn frames for the extra thickness. y'know you should have this fingered out BEFORE you build. Plywood is freakin strong. the boat will probably be better, keep on saving weight @ the same proportion. i.e., no bent frames, no conventional clamps or shelf

[Jlaup]

So, time for some more detail, sorry. There are 6 sawn frames, 7/8" x 2 3/8". The sheer clamp 1 1/4" x 1 3/4" sits on the inboard side of these 1 1/2" below the sheer to support the 1 1/2" deck frames. That will be going in as specified. I am happy to call my sheer stringer an inwale, but did not as these usually (I think) sit inboard of the bent frames. Most of the reason I propose the inwale is to give me more than the 3/8" edge of the ply sheer strake to nail the deck to.
http://farm5.static.flickr.com/4064/4349698156_2ceb134a5c_b.jpg

[Thad]

Since the plan shows a rub rail why don't you put that on before laying the deck for fastening along the edge -- you're going to glue the deck to the plank edge anyway aren't you? as all the rest of the hull is glued ply.

[johnw]

Here's how I did it on Black Swan:

http://lh4.ggpht.com/_Qk62rRa2hGc/SiQVy09wNcI/AAAAAAAAAds/0mYieSTjoPY/s512/IMG_0077.JPG

3/4' Western Red Cedar up against 1/4' okume ply. Seems very solid, and I can change the rub rails whenever I want.

[wizbang 13]

designer says teak may be used above wl only? that sounds daft.

[Canoeyawl]

I would be tempted to notch the forms and fit and glue the part directly against the planking as you suggest. I would use about a 1/2" (molded) x 3/4 piece. I'm thinking your rubrail will also attach to this... (edit- The rubrail fasteners will go into it)
Assuming the deck will be glued, the deck fasteners can be minimal.
Using steam bent frames you can just bend them a bit inboard to land on it it. A rivet at the top, under the rubrail, and at the lap should do it.
Sort of a tumbled home frame!

[wizbang 13]

i wouldn't use the "rubber" to carry the deck

[Jlaup]

Okay-

I like Terry's plan. I am going to put in a 3/4" sided by 1 1/2" inwale. The 1 1/2" will match the deck beams making fitting those a bit less complicated. I will put in a ledge to rest the deck beams on as shown in the plan, but reduce its scantlings by the size of the inwale. I want to keep the mass at the rail at what was specified. The ledge will give two nailing points along with epoxy for the deck beams, one sideways from the sheer strake and one down from the beam to the ledge. One of my goals throughout this project has been to keep the amount and location of displacement as close to the original as possible. The boat is over-canvassed as is, so reducing weight is not a goal. I want to keep it low, however.

The rub rail can't really act as a support for the deck as it is a canvassed deck and the rub rail will cover the edge of the canvas and the ply edge of the plywood. The toe rail needs to be taken into consideration as well in terms of a screwing bed (pun unintended.) The toe rail ends at the cockpit (more or less.)

BTW, the sheerstrakes are not on yet, so letting the inwales into the frames is not difficult. I think the picture does not make that clear.

Thanks everyone. I promise I have been thinking about this issue since June when I started on the Indian (I am going to have to name her one of these days-'Eleanor' after my grandmother, I think.) But, now that it is decision time, I thought it was time to ask for help.

John

[purri]

Yes, there should be a sheer clamp, and no, do not put in the steamed frames.

The sheer clamp is notched into the sawn frames and should have gone in before the planking started, but can still be added. The clamp greatly strengthens the deck to sheer clamp connection and gives a solid backing for the rub strake.

Agree, a sheer clamp is essential.

[Jlaup]

Here's how I did it on Black Swan:

http://lh4.ggpht.com/_Qk62rRa2hGc/SiQVy09wNcI/AAAAAAAAAds/0mYieSTjoPY/s512/IMG_0077.JPG

3/4' Western Red Cedar up against 1/4' okume ply. Seems very solid, and I can change the rub rails whenever I want.

I am thinking of using a gusset rather than a short beam around the cockpit, as well. But that does give some extra mass up higher in the boat.

[johnw]

I am thinking of using a gusset rather than a short beam around the cockpit, as well. But that does give some extra mass up higher in the boat.
Not quite sure what you mean. I used triangular supports because triangles have difficulty changing shape. The triangular support is made with three pieces of 2X1 pine. I made them with a 1/4' plywood backing, so that the join between the angles isn't stressed as much. Black Swan is a hard-chined boat, so the setup transfers the crew's weight to the sheer clamp and the chine log. Here's a view from the stern before I installed the cockpit carlins:

http://lh6.ggpht.com/_Qk62rRa2hGc/SiAvdmxrlmI/AAAAAAAAAcA/1Nw1F5MIfxE/s640/IMG_0069.JPG

(The white stuff is foam flotation.)

[Jlaup]

John, I see that it is not a solid gusset. The solution you used has good strength and light weight. As you can see the traditional approach on the indian is a short deck beam to a carlin. It is not as strong. The coaming works a bit like an i-beam on that system.

[johnw]

So, time for some more detail, sorry. There are 6 sawn frames, 7/8" x 2 3/8". The sheer clamp 1 1/4" x 1 3/4" sits on the inboard side of these 1 1/2" below the sheer to support the 1 1/2" deck frames. That will be going in as specified. I am happy to call my sheer stringer an inwale, but did not as these usually (I think) sit inboard of the bent frames. Most of the reason I propose the inwale is to give me more than the 3/8" edge of the ply sheer strake to nail the deck to.
http://farm5.static.flickr.com/4064/4349698156_2ceb134a5c_b.jpg

This shows a cantilevered structure. The deck beams are tied to the frame, and braced by the sheer clamp which runs inside the frame. You don't even need much in the way of frames, so I think you need to design some other solution. Maybe a sheer clamp tied to the top plank and a stringer underneath so you have something for the support to land on.

[johnw]

No, you probably don't need the bent-in frames. But then, you probably don't need the 'stringer', either.
But if he doesn't need the frames...

[johnw]

Right. If the sawn frames are still there, the original structure should work. I was thinking those were the ones mmd was talking about, but probably not.

[johnw]

Well, the Indian is a swampscott...

[johnw]

Sailing on David Smith's Chesuki is one of the high points for me. Growing up in Maine, my family knew someone with an Indian, but I never got to sail on it.

[stevedwyer]

I understand the Indian is actually a Sam Crocker design that he drew when in the employ of Alden and, as a result, is usually labeled as the Alden Indian, whether justifiably accurate or not.

Steve

[Jlaup]

It is actually the version I am building:
http://farm4.static.flickr.com/3530/3979010982_b1cfc14f8a_o.jpg
Although, I think I will bring the coaming up closer to the mast as is drawn in the later boats. The drawing above looks like a round coaming like a beetle cat. Hard to know without a construction view.

[Songololo]

Jlaup, have you seen this thread (http://www.woodenboat.com/forum/showthread.php?t=99737&highlight=carlin)...

http://farm4.static.flickr.com/3153/3737186266_4b53b19afd.jpg
http://farm4.static.flickr.com/3440/3737187738_22c22c5c12.jpg

[Steve Paskey]

A question about the original post ... John says that he's building the boat from 3/8" sapele ply rather than the 5/8" pine specified by Alden, which will make his boat much lighter than one built in solid wood. Am I right in thinking that he should plan on making up the difference in weight with removable ballast inside the boat?

[rbgarr]

A fifteen year old, Eric Dow-built, Indian for sale at Howard Boats:

http://i47.tinypic.com/21jnfwx.jpg

[Canoeyawl]

African mahogany weighs in at 35-50 lbs/cu. ft.
white pine is only 25 lbs/cu ft.
You may find that the plywood version is actually a heavier boat.

[stevedwyer]

As I see it, a shear clamp is the way to go. Good for joining the deck beams to. Iain Oughtred's book "Clinker Boatbuilding" might be helpful.

I have long admired the Indian design and you are doing what I've thought about building. Ah but the work space is lacking...
I'd really like to see more photos as building progresses!

[Canoeyawl]

I think it should have a "doubler" at the top of sheer plank to fasten the rubrail to. (back to the original question!)

[johnw]

So, in essence, two sheer clamps?

[stevedwyer]

Either way, you should probably end up with a 3/4" thickness for the sheerclamp. 3/4" mahogany is not that hard to bend in this application, but you could do it with two 3/8' strips.
and yes, the frames need to be notched for a tight fit. In fact, the frames, if notched and beveled for the planks may likely be the toughest joinery on the boat.

I use a jig for laying out the floors and frames, after suffering through trial and error. I take a stick and temporarily screw scrap pieces of 1/4" plywood at the plank jogs. This also gives the angle of each plank. Taking it off the long point of the frame (bevel forward or aft from amidships) I only have to wrestle with getting the angle of the bevel to fit.

You may be able to get by if you don't bother to notch for the jogs of the planks. Then you only have to notch for the sheerclamp.

[Canoeyawl]

I think he's using bent frames...

[Jlaup]

I did the math on the 3/8" sapele vs 5/8" pine and got them as being pretty close in weight. That is why I chose it. The sapele is less than 3% lighter than the pine. I was planning on using ~ 500# of ballast. I tested 3/4" fir and it bends easily around the sheer from the stem to form 3. There isn't much bend astern of this. A 3/4" inwale plus the 3/8" sheer strake gives me 1 1/8". Letting the inwale into the frames seems straightforward. This is what I build when not driving my wife crazy in the garage:
http://farm5.static.flickr.com/4056/4367053158_47778a2079_b.jpg
http://farm5.static.flickr.com/4029/4366305923_6b522fffd8_b.jpg
I think with an epoxy fillet and a couple of ring nails, I won't need to let the deck beam into the inwale. Although that looks like very sweet work. The rub rail is 1" half-round and the toe rail is 3/4" x 7/8". Seems like the inwale will give plenty of bed for those and the combination is a lot of mass (for a modified Swampscott dory.)

[Jlaup]

One other thing, and I know this is controversial, but I hate routers. My favorite tools are a sharp japanese saw and a set of very sharp japanese chisels. I spent most of 1977 and 1978 building furniture w/ my best friend using only 18th century hand tools. We built a forge and made most of them. Outside of production work, like those damn chairs, I can cut a joint (not smoke one) by hand much faster than I can build a jig, figure out why it is slightly off, shim it, and then loose concentration while using the router which will ruin stock faster than any tool I know. I know, what's a luddite like me building on glued ply. The next boat will be a traditional Rob Roy sailing canoe (I hope.) I get the the evil, I'm gonna divorce you , take half your money, and leave you with the problem 18 year old daughter look whenever I mention 'next boat.'

[Songololo]

Here's a Melonseed 16' build pic showing inwale and deck beam construction:

http://i209.photobucket.com/albums/bb294/melonseed16/045.jpg

More details in this post (http://www.woodenboat.com/forum/showthread.php?t=67626).