New construction: planking before deck beams?

[Seth Wood]

I realize this is a pretty general question, but here goes.

This is new construction, a 30' plank-on-frame sailboat. The books I've read all say complete the planking, THEN install the deck beams and decking.

But I'm thinking that doing the deck beams first will brace the hull and more rigidly define its shape before the stresses of planking.

What are the reasons for planking first? What am I missing here?

[Thad Van Gilder]

It is much easier to install the shelf and clamp without the deck beams in the way.

[TimothyB]

What Thad said..

Plus, the deck beams are not always necessarily attached directly to the frames.

Frames are usually cross-braced while planking though, so I don't think you would gain anything much by putting in the deck beams first, even if they were all attached to frames with bolted knees, gussets or some such.

But then, I'm not a pro. This is all just from an engineering point of view. I'll reserve my opinion on their advice.

[Dan McCosh]

Never planked a hull, but I would assume that you would want the planking and ribs to be tightly fastened before other major crossbeams are fitted, if only to insure the planking and ribs lie as fair as possible.

[Dave Fleming]

Hmmm,not necessarily planking before deck framing.
;)

http://pic4.picturetrail.com/VOL780/3097474/6299287/80939527.jpg

[Seth Wood]

Aha, right, that's exactly what I was talking about. It seems "right" to have the skeleton of the boat -- frames, deck beams, carlins, etc., and then proceed to planking.

But why or why not? Is this going to be one of those situations where I do it one way and then, halfway in, think "oh, that's why nobody does it this way..."?

[TimothyB]

It might just be for the simple expedient that it is easier to work inside the boat while the decking is off her. If you were riveting, it might be easier since you could stand right up inside her. Trunelling through and through would be easier as well. But then, as Dave shows us, there is more than one way to frame a boat.

It might be easier in other respects to do the deck structure before planking since you can reach up inside and behind, under and around various members for fastening.

Good question! One of those that doesn't get asked.

[Dave Fleming]

As this photo shows the structure of the vessel used as an example here is quite stout.

Harpin with frame ends through bolted several clamps, bilge and sheer etc..

http://pic4.picturetrail.com/VOL780/3097474/6299287/80939534.jpg

[Ken Hutchins]

Another thing to consider is what you are going to fasten the planks with. Screws the sequence doesn't matter as much as rivets. With rivets to peen, the deck beams will be in the way.

[Art Read]

Build her upside down and you won't have to wonder! ;) All kidding aside, I think planking without the deck structure in place on lightly built boats is pretty standard. The planking, for better or worse, helps "define" the final hull shape. The rest of the boat just has to "fit" what you've already done. As Dave shows, on sawn timbered, double framed, keelson fitted "major" vessels, deck structures usually went in at or just after the hull frameing. Before planking and ceiling. (But remember, they have more room to work around in there...)

Thirty feet? I think you're right on the borderline. FWIW, my gut says plank her first... That size hull, and it's scantlings, will still allow quite a bit of "wiggle room" when it come time to fit the deck structure... And a planked hull will provide alot more substansial structure to work with while you add that critical deck reinforcement. You can even build, and leave, all the building molds in place while you plank up without preplanning those pesky "work arounds" for the deck components...

http://www.imagestation.com/picture/sraid10/pbaaed6f9366b54a550716612c0d8fdb4/fe09298b.jpg
http://www.imagestation.com/picture/sraid15/pf20138b16edc1cd61a6a17d4ce9374b2/fdebb417.jpg
http://www.imagestation.com/picture/sraid15/p748d622059d2ca226af85d71dd69b31a/fdebb418.jpg

http://www.imagestation.com/picture/sraid12/p784a803da8c21e18074b38ebccd9bf2f/fe1a4ab8.jpg
http://www.imagestation.com/picture/sraid16/p2c75ac7074ab2d1ebd32d3ff6fe667fa/fdf42650.jpg
http://www.imagestation.com/picture/sraid16/pc687b2c0cfee46ccea6a65fec3b21b5d/fdf3df84.jpg

http://www.imagestation.com/picture/sraid21/p6160b6f097116509be6b3edc4674ac78/fdb12197.jpg

(Then again... This was just my first boat, your mileage may vary...)

[ 11-01-2005, 02:04 AM: Message edited by: Art Read ]

[Dave Fleming]

Art, that vessel was steamed single framed but, your comments on the whole I am in agreement with.

[Stephen Hutchins]

To me, the most important reason for planking first is to ensure fairness. Putting deck beams on first forces the final hull shape, for better or worse, and the wonderful thing about wood planks is that they are self fairing, like a spline is for the draftsman. It's nice to be able to see and control final shape of the sheerline. If you have already put the beams in, and you have doubts of the final apearance, you could always fit a trial sheer plank.

[ishmael]

Another reason to leave the deck beams till later is it makes working on the interior, placing the engine, plumbing, wiring etc easier. You can stand up inside without ducking between beams.

Some people build the furniture before much hull planking! It's easier passing pieces in without.

Two or three braces work well to keep things from spreading.

[Seth Wood]

Thanks, everyone, this is great advice. Planking first it is, with frames cross-braced. Which make sense: letting the planks determine final hull shape, not the deck beams.

Thanks again.