Deadrise With Flare

[jim_cricket]

We’re back at work on a new skiff in Deltaville, at the DMM Boat Shop. We think we’ll build at least two skiffs in the 18-20’ range, maybe a 16’er. All rack of eye on a modular jig that works for any skiff from about 16- 20 feet. One 16 has been built on this setup already. The newest skiff looks like she’ll measure 18’-9” from the stem rabbet (inner stem) to outside of transom, so 19’ or so LOA. Beam is variable at this point, and we won’t really know that until the bottom is upright, and the skiff is framed.




This jig frame is leveled, then rebar stakes are driven into the ground to lock it in position. You can see those in the corners. Once the bottom is planked, we'll lift it off
and will set it upright on the other side of the shop. We can then start another boat on this jig, and have two skiffs going at the same time.

We’re going to set this boat up with some concave flare in the forward topsides. The stem is set at 17 degrees and the transom rakes15 degrees aft. Most of the recent skiffs (except the large Norris skiff just launched) are spawned from an old Lewis Wright 18’er that John England and Larry Chowning measured on land before she fell apart. That’s a fairly narrow skiff, and this new one will have more beam, particularly on the bottom at the transom to support a heavier outboard. The rough sketch here is from that old skiff.


This old skiff has now completely fallen apart.


We made several changes from these dimensions. That's the beauty of this kind of setup. You're not locked into a set of molds.

The shop acquired a lot of Willard Norris' old patterns and whatnot when he passed away. We have a stack of old flared frame patterns that he used. We may pick one of these as the starting point for the flare on this new skiff.



...continued in next post

[jim_cricket]

Re: Deadrise With Flare

...continued

The keel is laminated from stock dressed fir- 1-1/2” in the center, with 1” on top and bottom. We made the keel about 17’ long, and some of the stock was 16’, clear and straight. We just butted two of the layers with little foot long pieces in the ends, but the top layer was from an 8’ and a 12’, with a 10:1 scarf, as that joint falls more in the middle of the boat. The keel blank finishes 3-1/2” x 5-1/2”, a nominal 4x6. Not massive, by bay standards, but beefy enough. We are taking some deadrise to the stern, so the triangulation helps the stiffness as well.



We got out the transom from 2 x 8 clear fir, two 12’s in this case. 1-1/2” finished thickness, with a 3 x 8 knee. It will be framed on the inside as well. We had a big hunk of fir 6 x 12 that we are getting stems from. Split in half, a 6 x 6 x 48” yields two stem liners (inner stem). We set up a bevel cut on the big bandsaw to rip the complementary bevels. The stem liner’s molded depth is 3-1/2” x 4” on the inboard face, and about 7/8” outboard at the keel to 1-3/8” at the sheer. This is just a preliminary dim, leaving plenty of beef for fairing when we start planking.


Transom boards are splined and glued. Cauls help keep it all flat during glue up.


Stem liner-I cut close to the lines with a power plane, then finished up with a hand plane.

With the keel laminated on top of a straight beam, the stem, plus stem and stern knees were glued and bolted on to the keel. We’ll have to dig a small hole in the ground for the stem, then we’ll set up the backbone assembly on the jig. The transom was cut out, with a 2” deadrise on the bottom, beveled to 15 degrees. That will get propped and braced on the jig, then once everything is set up true, we’ll glue and bolt the transom to its’ knee. The side cuts are left unbeveled, to fair on the setup. The beam inside plank at the transom sheer is 64”. Normally we hold the same 17 degree topside angle at the stern as we have amidship, but we widened the bottom on this one, so the angle is much less. There is some concern that looks too boxy, but we can re-cut the sides of the transom and tuck the bottom in a little more. We’ll have to look at the whole picture. There may have to be a compromise between bottom width and appearance. It has to look good.


By changing the angle, both stem and stern knees can be gotten from one pattern.


Stern knee.


Stem liner, knee, and keel.

Many boats with concave flare also have flam (convexity) and tumblehome at the stern. Deadrise workboats, at least the classic cross planked skiffs I’ve seen, usually carry a straight angle at the stern, and of course some bigger boats fair the angle into a round stern. I posted some of these pics on a Facebook page, and had some comments that the concave flare won’t work without flam, and that “you got to shove her off more”. Anyone here familiar with that term? Never heard it before. I asked what he meant by “shoved off”, but didn’t get a reply. A Carolina flare term? Somebody fill me in!

That’s enough of a book for now. Stay tuned.
Cricket

[leaotis]

Re: Deadrise With Flare

Oh boy, I'm tuned in.

[hawkeye54]

Re: Deadrise With Flare

Would be nice to sit in that 'moaning chair' with a cup of coffee, and just observe the build going on . . . . Great job so far !




Rick

[Peerie Maa]

Re: Deadrise With Flare

Waiting with bated breath to see the chine streak hung, so that I can visualize her shape.

[jim_cricket]

Re: Deadrise With Flare

We now have the backbone and transom set up on the building jig. The stem went in a hole just 6 or 7” deep. It’s a dirt floor, but feels like concrete. I broke a hammer driving a brick chisel to break it up. We needed a longer spreader for this boat, which has more beam than the last one, so we put that on. That spreader, by the way, goes 18” fwd of the keel mid point. That location automatically puts more beam in the portion aft of amidship when the planks are hauled into the stem. We can also spread the chine fwd of the spreader for more beam in the bow. The spreader ends are cut at the angle we want the topsides to be.




Transom bracing.


The stem has a brace running up to the ceiling. It's a head banger, hence the safety towel.

We bent a couple of battens around the set up to get a quick look at things. We all think that the transom is too boxy, and this morning I recut the sides of the transom. That reduces the beam at the waterline, but it’s still close to 60” at the waterline. I don’t have pictures of the recut transom yet. The end on view shows the old angle. We may recut it again, but we want enough bearing back there for a reasonably sized motor. Give how well the Point Comfort 23 did with the Suzuki 60, I think a 50 will be nice for this 19’er. This one is proportionately wider than the PC though. The 50 is the same weight as the 60, but costs less.


Original transom layout. Too boxy. We'll finalize the side angles back here when we try out the chine planks.

This morning, John brought over a couple of cedar boards for the chine planks. These were 14-15” wide, and 20’ long. Perfectly clear. This is some of the last of about 16,000 board feet that he bought 10 years ago. I don’t think there’s any more stuff like this anymore. The chine planks are tapered to make up the difference in span from bow to stern. We’ll strip plank the topsides above the chine plank, due to the flare. One interesting thing about the chine planks, is that a curve is cut in the bottom edge, with the deepest section at the spreader location. This is common practice on deadrise power boats, and does two things. I lowers the chine and increases deadrise slightly at that location, and it flattens the chine in profile. A straight edged plank creates a hump in the chine, and affects the waterplane. On this boat, the hollow is 1-1/4”. Larger boats use more hollow, and the location of max hollow can shift fore and aft to change the location where the chine breaks out. We marked this out with a batten, and made the cut with a skil saw. One of the planks had some built in tension, and the cut straightened out. The other plank stayed true, and I’ll use that one with a pattern bit on the router to true up the first one.




The batten is set to the hollow cut in the chine plank. We'll hang these planks today.

Stay tuned!

[Thad]

Re: Deadrise With Flare

Beautiful stuff. Hello John! Fun!

[Bill Perkins]

Re: Deadrise With Flare

It seems the floor is some type of Stabalized Earth . Did digging the hole give you any insight into its composition? Boiled Linseed oil topcoat ? Easier on the feet than concrete?

[Peerie Maa]

Re: Deadrise With Flare

It seems the floor is some type of Stabalized Earth . Did digging the hole give you any insight into its composition? Boiled Linseed oil topcoat ? Easier on the feet than concrete?

If the shop is old enough it was probably milk, on the turn, pounded well down.

[timo4352]

Re: Deadrise With Flare

Love seeing a new build from you Jim.

[jim_cricket]

Re: Deadrise With Flare

Thanks everyone for your comments! I’m loving working in this shop. To have a boatbuilder like John England running the show is a real learning experience for me. I’m losing some of my fussiness, and picking up speed with the joinery.

Over the last couple of days we made some adjustments to the setup, widening the spreader and recutting the transom side angles. The boat is looking pretty good. We permanently hung the chine planks, got out and fitted the logs, then installed those permanently.




The second plank always requires a custom clamp block. That beveled block is screwed to a scrap board, then clamped to the first plank which has already been hung and fastened.


This view gives you a pretty good look at the deadrise forward.


The chine logs are cut from some clear, 5/4 treated pine decking. We use this economical timber in several applications on the inside of these boats.


Logs are glued, clamped, and screwed.


Roland has a look at the afternoon's work.With three of us working, it goes pretty smooth. It would be tough to get these logs bent in and clamped working solo.

We had enough time yesterday to start prepping stock for the bottom planking. This cedar stock is anything but clear, but the cross planking is short, so we can cut around some of the worst knots, and we are double planking the bottom, with the second layer running diagonally, and epoxy glued to the first. But I’m ahead of myself. We’ll look at that, as well as beveling the keel and chines next time.

Thanks for looking!

[CollinR]

Re: Deadrise With Flare

Looking good, I'm on board!

[amish rob]

Re: Deadrise With Flare

Yes. This is all so much yes! I’m mad jealous at all the fun that must be.

Thanks for taking the time to document this.

[willin woodworks]

Re: Deadrise With Flare

taking notes...

[Peerie Maa]

Re: Deadrise With Flare

There is a stern quarter image posted on FB which shows her shape to perfection.

This is going to be a good build.