double sawn vs. laminated frames

[centroid]

Hi, I’m not fabricating frames at the moment, but I’m thinking ahead for next year in case I need to purchase timber now to dry.

The issue is laminating vs. double sawn frames. The boat, 24’7 cutter, white oak backbone, carvel plank. I know the pros and cons according to Pardey’s book as far as structural. But I want to discuss amount of materials and amount of time to do double sawn frames vs. laminating them out of white oak and resorcinol.

Does double sawn take much more time ? I know it requires more material, tripple the amount according to the plans. I was thinking of getting wide quarter sawn, vertical grain white oak, air dry them now until next year (5/4 rough, 4/4 net, 1 year per inch of thickness). Is this not a good idea since they do not have many crooks in them ?

For laminated frames, it would be 1/8” thickness, 16 layers. Save more materials but there’s the jig building, and possibility of glue separation. There’s glue in both but more chances with laminated frames. Double sawn would have copper rivets as back up.

Comments ?

[paladin]

Take your time and laminate the frames...

[bugeye]

HI,
laminating takes alot more time. sawing, planing, gluey mess, cleanup, planing again, beveling. If you can get creative and get some crooked stock, you can do sawn frames very quickly, strongly, and in few pieces. Plus, grown crooks are much more interesting.

[centroid]

bugeye-

i was looking at purchasing 1/8 thick stock in random lengths, that way, i won't have to do the milling process. just sanding to rough up the surface and washing maybe. the price in materials for both method would be about the same.

i don't know if i can get grown crooks. its pretty much the local white oak, quarter sawn. but the boards can be nice and wide to get the curves in.

[ford]

if you're worried about speration of laminated frames,fasten them as well,apart from that, I believe laminated is stronger anyway.

[bugeye]

HI,
If you can talk to some local loggers or arborists, you can often get the wood that you want for free. It is definately more of a hassle than going to a sawmill or lumber dealer for what you need, but I've found the results worthwhile. It shouldn't be hard to find someone with a wood-mizer to saw it for you. I realize that this might be more than what you're wanting to do, but you might have fun with it. I consider it part of the fun of the whole boat building progress.

[Thaddeus J. Van Gilder]

OK, first of all double sawn frames mean that you don't need crooks. Yes It makes for less futtocks and yes that makes them quicker to make, but you don't have to do it that way.

If there are any big wood fish boats around you or big "tall ships" (for lack of a better term.), look at their futtocks. They are cut from staight stock. The 4 by 4 double sawn frames in my cutter are also cut from staight stock. There is a william Hand 56 or so foot motor sailor nearby that is getting the same treatment.

I would take any crooks you get and use 'em in the bow for single sawn frames, and double sawn all the others. They will be plenty strong enough.

Thad

[holzbt]

I would not consider double sawn frames UNLESS you have access to a pile of crooks. In a smaller boat such as you are considering the curves are much tighter than in a larger vessel. Using straight grain stock will give you considerable runout of the grain unless you use so many futtock sections as to weaken the frame due to excessive number of joints- a lose-lose situation. The laminated frame will be stronger and lighter although more work if you add in milling the stock.

[ 09-27-2002, 08:11 AM: Message edited by: holzbt ]

[Thaddeus J. Van Gilder]

Holtzbt,
I disagree.
My 27' LOD cutter has double sawn frames , with the futtocks cut from straight stock.

In "Cruising with Serafyn", It is mentioned that Serafyn is frame in Mahoghany. I have never seen nor heard of a Mahoghany crook. Therefore, I feel it safe to assume her futtocks were sawn of straight timber.

[Jim Budde]

An interesting discussion ... but I need a short class in terminolgy. I think I know what double sawn frames are ... I do not know the term futtocks. Would you mind refreshing me on the former and enlightening me on the later? Thanks

[centroid]

holzbt and thad.
i think you are both right. the more crooks you have, the better off you are because you will have fewer futtocks. however, you can build up the desired curve from a series of straight sections. i think too many futtocks will weaken the frame though.

thad.- 4x4 double sawn frame. i assumed its not every frame but maybe every third @ 9"0.c.

this is another issue to point out. seraffyn was built with a double sawn frame and two steam ones in between. i was planning on all sawn or all laminated. sawn 1-5/8 sided, 2-1/4 molded. lam. 1-1/2 sided, 2" molded.

another question: lets say you need a 1-1/2 laminated frame, can you use 3" wide laminations and saw in half ? thus creating two frames for every single glued attempt.

[Norske3]

Punch in "double sawn frames"...WBF search department under Building/Repair...lotsa info there... smile.gif

[bugeye]

Thad,
I didn't mean to imply that one can't make sawn frames out of straight stock. In a small boat like the one we're talking about here, it would be foolish to use straight stock though because you'd have a multitude of futtocks in very short lengths, or if you gave into temptation and used wide stock to give longer futtocks, you would lose alot of strength because of cross grain. My bugeye has double sawn frames, made of a great deal of compass timber, with straight grained stuff where her hull shape makes it appropriate. When I was reframing, I happenned upon a construction site where a good stand of very curvy locust trees had to go. I got them for free, save for the my labor in cutting them. That was a godsend. There were many places where I removed two futtocks and replaced them with one. I remember seeing Mercantile, one of the Maine windjammer fleet, with her ceiling torn out. She had been framed with curved branches in double sawn fashion. Some of the futtocks had bark on them and little branch stubs sticking out here and there. It was crude, but it had served for nearly 100 years.

[Allen Foote]

Go to your local saw mill and buy the lesser quality white oak...the kind with the knots. Have it slab cut....quarter sawing is for steaming. Now, notice how the grain twists and turns around everyone of those knots. Using the grain pattern, cut longer pieces that fit tight to the hull before runout. BUT, double sawn will add alot more weight to the hull...thus steamed or laminated frames between double sawn. Yes, you can overbuild your day-sailor. :D

[ 09-29-2002, 05:53 PM: Message edited by: Allen Foote ]

[Bob Cleek]

Whoa... wait a minute. Once in a while, there is something new under the sun. Given the time and expense of laminated frames, and modern adhesives, I can't imagine why anybody wouldn't opt for sawn frames. Forget a lot of the old stuff about their having to be huge and massive and heavy and all that. Make up TRIPLE sawn frames out of slash sawn stock so the grain is running parallel to the molded dimensions. Three layers will avoid the inherent weakness at the futtock butts. Use Aerodux if you are using oak, since you just can't trust epoxy. Rig up a scarfing jig for your router so each butt is scarfed, maybe 6:1. (If you scarf, you could probably end up with just double sawns, but the triples are bullet proof.) What you get is a glued up (flat-laminated if you will) "crook." Saw that to shape, bevel it and all. With triples, you will find your plank fastenings should just about land in the middle of one or the other of the outside futtocks. Best holding ground right into virgin wood. The glued futtocks will just about eliminate any concern about grain going across the curve. No metal through futtock fasteners to foul the plank fastenings, either. Think "monster three-ply plywood!"

[imported_Conrad]

Laminated with rivets- it's the lightest(more ballast), gives you the most usable interior volume, eliminates concerns about grain patterns, holds fastenings very well (with no worries about hitting solid wood) and isn't that much more work once you get into the swing of it.

[capt jake]

Laminating is a snap! Building the jigs isn't that hard either! I have some laminated cabin beams in my little boat that are made form 1/4" strip (5 of them) with epoxy. NO spring back when released.
Laminate! smile.gif

[centroid]

Hi,

Very interesting discussion.

I just wanted to ask if anyone has worked with or seen a delaminated frame after years of use. I’m not talking about frames that come apart during the gluing process because of wrong temperature or humidity.

I talking about laminated frames of an older boat that delaminated from:
1) planking screws pulling laminations apart
2) or cracking of frames in the sided direction from floor-to-frame connection
3) or frame ends being subjected to more moisture from wet bilges or any other reasons.

I guess I would like to know similar cases in double sawn also. The one condition that Lary mentioned is due to a butt joint of the frame so that can be substituted with a scarf joint.

Thanks

[Lulworth]

Am I missing something? Why wouldn't you steam bend your white oak frames? Unless the design is hard chine and/or specifically calls for sawn frames, I would have to recommend steam bending. On a 24 ft boat the frames are not all that thick (moulded or sided) and I can tell you that steam bending frames is actually pretty darn easy once you get the hang of it. Think of it as five intense minutes per frame of grunting and struggling to get the oak to bend the right way versus hour(s) of fiddling with epoxy laminates or fitting fruttocks. Just a thought, David.

[Thaddeus J. Van Gilder]

That is true. steam bent frames are the easiest way to go.

I have indeed seen delaminated frames. most of these were in daysailors, with the exception of one sportfish.

I don't know what the glue was in the small sailboats, but the sport fish was restored with epoxy, and the frames cracked the first trip out side, presumably from the pounding the boat took in the inlet.

[centroid]

About steam bending, I do agree that it would be the EASIEST way to go. But I don’t think it is the best structural connection at the floor to frame to beam joints. The molded side of the frame is not 90 degrees or normal to the floors or beams. You then rely too much on your clamps for that connection. Not as strong I believed. The bevel on the sawn frame or laminated frame allows the floors to be connected to every frame at 90 degrees, then you can install floors on every frame also. Just an idea, I would like to hear other opinions on that.

Thad- how did those cracks occur ? because the frame was undersized ? split at glue joints ?

Its seems like if I was to go with lam. Frames, then use copper rivets and resorcinol. If sawn frames, then copper rivets, resorcinol, and scarf joint for futtocks.

[Roger Cumming]

What has not been discussed is: what type frame is most appropriate for your boat. If you are building a Spray replica, double sawn frames are the way to go. If you are building a lighter, more modern boat, steam-bent or laminated is the way to go. The merits of each technique are directly related to the design of the craft. The idea is to wind up with a boat appropriately constructed for its design and use. Laminating frames for a schooner that will be carrying inside ballast doesn't make sense. Nor do double sawn frames in an outside ballasted racer. The question of what type of framing answers itself if you think about it. It is then simply a matter of procuring the appropriate materials to frame the boat appropriately.

[centroid]

roger,

thanks for that answer. i think that is a very good point. when i think in those terms, it does reveal itself more easily.

in building this boat, i want to constantly remind myself to not make too many short cuts just to finish. i want to create a boat that demonstrates qualities of beauty, craftsmanship, and tradition.

[George Roberts]

A lot depends on the sizes of the frames.

Your frames appear to be 2"x2". It appears to be a bit small for double sawn frames. It appears to be a bit large for steam bending.

I think I would laminate and use very long screws to fasten the planking.