New Design - 22' Powerboat - abuildin'

[mcdenny]

I'd been noodling out a more perfect (for me) power boat and posted the final design here last June:

http://forum.woodenboat.com/showthre...ink&highlight=



I finally got around to starting the lofting in July and got the wood & 6 gallons epoxy in mid-August. It has taken until now to get the frames, keelson and stem setup and glued together. Go slow now so you can go fast later is my new rule so I'm getting two coats of epoxy on everything and sanding with 220 before gluing the part into the boat.




The frames and stringers are 7/8 Sassafras, keelson is a layer of the 7/8 Sassafras and a layer of 3/4 Meranti ply. The three bulkheads are 1/2 Meranti ply with a 1/4" layer of Sapele glued on to the show face. I wanted to use 3/4 Sapele ply but the stuff they had at Johnson Lumber was only 5 ply with paper thin Sapele faces and weighed a ton. The veneered bulkheads look nice but were a pain to make. I should have looked harder for decent Sapele plywood.

Next step will be to set up the curved, raked transom blank and project the hull shape onto it from bulkhead 9 and mold 10.

Sides will be 3/8 Meranti ply glued lapstrake, bottom will be cold molded of two layers of 3/8 Sassafras. Chine flats will be strip planked with 3/4 Sassafras. There's a lot of fairing to do before the planking starts though.

[Breakaway]

Very nice. I will be watching this one.

Kevin

[skaraborgcraft]

Nice to see it in frame, lovely entrance. A lot of work ahead but will be well worth it. Cheers

[spirit]

Wouldn't you do better with coarser sandpaper to give the epoxy more bite?

[W Grabow]

Please keep us up to date with pictures and commentary. You are doing beautifu work. I hope to profit from your ideas for my next build.

[mcdenny]

Here's an update though there is not much to show for 5 weeks (very part time) work.


One side has the sheer clamp installed but not faired, the chine flat is finished. The other side has the chine flat strips glued on but not trimmed or sanded.



Curved, raked transom is four layers of 1/4" cedar. A final layer of 1/4" Sapele will be applied after the planking is complete. The deck curve and "tombstone" cutout will be done after the Sapele is on.


A better picture of the chine flat. The inner edge is one full-length strip bent into place just like a batten to make a fair curve. The rest of the strips are shorter pieces scarf jointed together, the whole gooey mess clamped to the inner strip in one operation.


Here is the strip scarfing jig I use with a chop saw. Well proven after the two 25' strip planked electric launches.


And finally, the stack of bottom planking stock (3/8" Sassafras) sorted into wide, medium, narrow, 6', 7' 8' subsets. The computer says I need 220 sq ft and I have 310 sq ft so a little waste shouldn't be a problem.

Next step, afer finishing port side chine flat and sheer clamp will be to remove the temporary mold just in front of the transom and install the motor well. Then on to planking.

[mcdenny]

Another week and a half and I have 25% of the bottom planked, the first layer on one side.

A days work to cut, fit and screw down the planks makes a huge difference in the appearance - there is skin on the bones finally.

Another days work to disassemble, goop and reassemble the planks and the boat looks worse at the end of the day than at the start.



But the joyous third day - when the screws, clamps and blocks are gone and the hull is sanded to a smooth uniform surface. Damn, that hollow forefoot looks fine!





This third day, where the almost final shape emerges from the clampy drippy screwy surface, is my favorite part of boat building.

Another course of 3/8 Sassafras will go on angled the opposite direction. That will bring the bottom flush with the edge of the chine flats.

[wizbang 13]

aw yea

[mcdenny]

First bottom layer, second side done.



I can just imagine the sharp forefoot cleaving the water.



Second bottom layer started.

[KylBak]

I love this boat! My next build will be something very similar to this... This thing is gonna be beautiful when its done! Keep up the good work.

[W Grabow]

Keep it up! I will be using you for inspiration and some guidance. Very nice work!

[Bob S]

Thanks for sharing your build. What are you using for adhesive?

[Tom Lathrop]

Denny, Do I detect a bit of down angle in that chine flat? Down angle relative to the aft bottom, that is.

[mcdenny]

Bob, Raka 127 resin with 350 non blushing hardener.

Tom, The chine flats are horizontal in the width direction but angle down a bit as they go aft. My hope is that they will act as trim tabs to hold the bow down as the hull gets up on plane. I don't think they will be immersed at all at planing speed.

This is my first experience at cold molding anything and it sure takes a long time. By the time the bottom is done I will have cut and fitted something like 120 pieces of wood. The pluses are though that it is 80 # lighter and $600 cheaper than using sheet ply plus I didn't have to have a developable shape.

[mcdenny]

Update - Bottom planking finished.

Post #6 above shows a picture of the 310 sq ft of planking stock I planed to make two layers on the 110 sq ft bottom. Well, the bottom is done and I have exactly 18 sq ft left over. The scrap estimate was 40% (it's a long way to the specialty lumber yard) and I needed almost all of it.

The inner layer was a lot easier to apply as it lays down relatively flat even at the bow. I used my widest stock (about 8") at the stern and needed to rip 2 1/2" wide strips to take the curve as I got up to the bow. The outer layer shown below curves a lot more. I went from 8 to 6 to 4 to 2 1/2 to 1 1/4" wide strips to get them to lay (sorta) fair. My trusty Makita belt sander with 40 grit made short work of the initial fairing pass.






On to fairing the sides and scarfing up a pair of 24' x 4' panels.

The Freeship panel expansion says I can get all seven strakes from one 4' width - barely. I'm going to make a 4" x 24' long spiling batten from 3/8 fir ply to pick up the plank shapes at the frame notches.

[Breakaway]

Nice. WIll a ply batten bend properly for a lining batten? Doesnt it need to bend in two directions and /or twist a bit? Mind you, I have never lined off planks--just asking.

Kevin

[jsjpd1]

Looks good so far Denny! Thanks for sharing!

Jim

[Tom Lathrop]

We have a treat here on the forum. Two builders of somewhat similar boats working from very different perspectives. Erster is building strictly from the seat-of-his-pants school and his long experience and Denny is working with computer modeling and the "full design before starting work" school. Mike lofts in place by eye (he doesn't even call it lofting, but that is what the result is) and Denny works from a fully lofted plan before frames or bulkheads are cut. Both build very good boats with craftsmanship that is the envy of most. I hope we are all following both builds. Mike knows what the end result will look like and adds pieces until it gets there and he has not a single piece of paper to show anyone what the boat will be. Denny knows that if he adds the pieces called for in his detailed plan that the end result will be what his plan called for.

http://forum.woodenboat.com/showthre...ghlight=erster

For those who think that there is only one way to do things, this should be an education. Good on you and I look forward to seeing and maybe riding in both boats.

[mcdenny]

Breakaway, the planking lines were defined in the lofting and notches cut into the frames accordingly. With the sheer line and the chine line faired, I divided the vertical distance between chine and sheer at each frame into seven equal parts. My intent is that the strake lines flow smoothly with the chine and sheer. The ply batten ( and obviously the planks themselves) will have some twist, a good bit at the sheer plank and not hardly any at the chine plank. Nothing like a complete lapstrake hull though where the bottom planks must twist 90 degrees to meet the stem.

Tom, I've been following Mike's thread with a lot of interest for just the reasons you suggest. I admire his work a lot (and you're too, from which I stole the idea for chine flats) and would love to get together with you and him when our boats are done. I bet WoodenBoat would do a comparison test of mine, Mike's and your BJ24. Just like when car magazines test a Camry, Malibu and Accord side by side.

[mcdenny]

Next step is planking the sides. The plank shape is picked up by clamping two 3/8" x 3/4" battens on the frames to represent the upper and lower edge of the plank. The shape is locked in with a web of diagonal cross braces hot glued to the battens. The pattern is pretty fragile buts works well to transfer the exact shape.



Detail of the cross bracing and "L" shaped wooden clamps holding the battens to the frames:


Then the strake pattern is laid on the two layers of 3/8" Meranti ply scarfed into 4' x 24' sheets:


A pair of planks are cut out with a jig saw, trimmed with a plane, edges are eased with some sand paper and the plank tried on the hull:


The "L" clamps, and a couple of "C" clamps, are used to hold the plank against the frames.

So far so good - six more pairs of planks to go.

[W Grabow]

I am impressed. It is going to be beautiful.

[erster]

I missed these updates. Thats a lot of work that you have done. The amount of room also makes many envious to jealous. In lapplanking once you have the general shape of the planking, its just a matter of taking that and extending the length from the maximum run of the previous shorter one. There is some play still in that length of run. So you should be able to move along a bit quicker now. It must be fun handling that long and flemsy pattern frame. Thanks for the words too. My work is almost stuck in the mud right now with some change of direction in a different area and project. But with the temps moderating hopefully later this week, the two projects will get my attention. Gotta work off all those cookies and cakes from the past two weeks that have bogged me down too....Burp......

[mcdenny]

Mike,

The pattern is real floppy and the battens by themselves are like picking up a wet noodle.

Hope to see some new pics of your project soon, after all only six more months until summer.

[brad9798]

AWESOME!!! Keep it up brother!

Brad

[Breakaway]

Ore-ess-ome!
Love that L-clamp.

Kevin

[Figment]

Then the strake pattern is laid on the two layers of 3/8" Meranti ply scarfed into 4' x 24' sheets:

(I get why you pre-scarf the ply sheets. Makes all the sense in the world in terms of workability and time efficiency. It did, however, prompt this thought)

Might there be a concern that all of the scarfs will pretty much line up on the boat instead of being staggered or offset a bit?
I know this isn't carvel construction, totally apples and oranges, still I wonder.
Is it a non-issue because the strength is in the continuity of the laps?

[Tom Lathrop]

Figment,

You can flip adjacent strakes fore and aft and that will insure that scarfs are not next to each other. Also, the varied length of the strakes allows for some scarf staqgering. The bigger problem with pre-scarfed sheets for lapstrake building on a boat with much shape to the hull is that it can waste a lot of wood. Besides, good scarfs can be just as strong as the plywood.

[P.L.Lenihan]

Might there be a concern that all of the scarfs will pretty much line up on the boat instead of being staggered or offset a bit?

It is a brilliant means of showing off ones' confidence in epoxy.Either you trust it or ya doesn't.....no half measures allowed.


Lovely design mcdenny and a great build thread! Looking forward to following your progress throughout the winter!!




Cheers!


Peter


P.S. Nice shop too!!

[mcdenny]

Tom, The Freeship panel expansion shows that all seven strikes can come out of a 4 x 23.5' sheet. We will see...

Figment, The bottom strake is about 8" less than 23.5' so the scarfs can be staggered a bit, as Tom said above. I think the scarf is just as strong as the rest of the ply but it just looks wrong if the joints line up. The inside will most likely be varnished so the joints will show here and there.

Peter, You live even further north than I do so will certainly understand why we are on our way to Florida for a couple of months and therefore no more updates until March.

[P.L.Lenihan]

Thanks for the warning but I'll never understand why folks head South like that every winter. We aren't geese,ya know

Have a wonderful warm time down South and I'll look forward to your safe return to this wonderful build thread.


Cheers!


Peter

[shade of knucklehead]

Can I ask where you got sassafras? I still have quite a pile of it in flitches, but its not a commonly used wood. The main problem we have around here is the trees are not growing straight, they are mostly curly looking things in the swamp.

I love working with it though, I built my entire bathroom in our old house out of it. Including making all new trim to match the other trim in the house. It was a hundred year old house with that beautiful trim that people don't use anymore.

[mcdenny]

Sorry for the delay responding but I just got back into Internet-land.

Sassafras is available at a couple of lumberyards here in SE Michigan, less than $3.00 / bd ft in wide clear pieces. Seems to me an excellent boat building wood, rot resistant, light weight, good machining characteristics, looks just like oak under varnish.

I get it at L. L. Johnson's in Charlotte, MI. I believe they will ship it to you.

Maybe it's called something else on the east coast?

[shade of knucklehead]

Nope, its sassafras. Its just hard to get here anymore. We used to use it (when my grandfather was running the shop) but have got away from it because we can't get it locally.

[mcdenny]

I'm back after a couple of months in Florida avoiding a Michigan winter that was strangely absent this year.

Here's a couple of pictures of the third strake being stuck onto the hull.





The home-made clothespin clamps from the Arctic Tern are getting used again here.

Thats the strake for the other side laying in the foreground of the first picture. It's sooo much easier to epoxy, sand, epoxy, scrape and sand on the flat bench than after it's on the hull and gravity is no longer my friend. It does slow down the progress though as the epoxy cure period means the fastest you can go is one pair of strakes each five days.

[ulav8r]

I've only had experience with living sassafrass, but the limbs are very brittle. They will snap off with little effort. I would have been leery of using sassafrass in this application. Do anyone know of successful use of it for this type of application?

[shade of knucklehead]

What application?

Its been used in boatbuilding.

[ulav8r]

The application used in this thread, boat building. As brittle as the live limbs are, I would expect the lumber to be a poor choice in a spot that might be subject pounding from waves, floating objects, or unseen rocks or sand bars.

[Breakaway]

SASSAFRAS
Sassafras albidum

---

Common Names
Black Ash, Golden Elm, Cinnamon Wood, Common Sassafras, File-Gumbo, Red Sassafras, Sassafrasso, Saxifrax, , Smelling-Stick, Wah-en-nah-kas, White Sassafras

History
Essential oil distilled from the root-bark or the fruit is used to make safrole, tea and as a fragrance in perfumes and soaps, food and for aromatherapy. The shoots are used to make root beer, which owes its characteristic odor to the sassafras extract. The leaves are used for thickening sauces and soups, and when dried and ground are known as filé powder, a spice used in Cajun, Creole, and other Louisiana cooking, such as the dish filé gumbo.

Did You Know?
Sir Walter Raleigh took sassafras back to England from Virginia. In what were called the Great Sassafras Hunts from 1602-1603, ships were sent from England to collect the roots. Sassafras roots then were converted into a tonic that smelled like root beer and supposedly kept its drinkers youthful and healthy. Sassafras was also used as dye to give fabric an orange tint.

Distribution
Sassafras is native to North America from Maine through Ontario, Michigan, Indiana, Iowa, and Kansas, to Florida and Texas. Average tree height is 30' to 60'

Main Uses
The wood of sassafras is used in the manufacture of furniture, interior and exterior joinery, windows, doors and door frames , kitchen cabinets and paneling. It is a preferred wood used in boat building and fence posts.

Relative Abundance
Together, aspen, basswood, cottonwood, elm, gum, hackberry, sassafras, sycamore and willow represent 12.5 percent of commercially available U.S. hardwoods.

General Description
Sassafras heartwood is pale brown to orange brown, resembling ash or chestnut. The narrow sapwood is yellowish white. The wood has a coarse texture and is generally straight grained. Well known as an aromatic species.
Sassafras is very resistant to heartwood decay, in exposed damp conditions however, the sapwood is liable to attack by powder post beetle.

Availability
Extremely Limited.

[mcdenny]

Thanks for the scientific reference.

Sassafras is very nice to work with, smells good, and is half the price of clear Doug Fir here in Michigan.

The battens I'm using to take the plank shapes are 3/8 x 3/4 sassafras, spliced to 25' length. They have been flipped and flopped around a lot in the planking process and are very limber, not brittle at all.

PS, whiskey plank is coming soon, hopefully next week. I'll post some pics when the planking is complete. So far I've got about 700 hours into the build.

[skaraborgcraft]

Nice one Denny,keep at it. Cheers

[mcdenny]

Finally finished the planking. My pair of 4 x 24 scarfed together sheets were just enough, only had a couple of inches of scrap left over. The panel expansions in Freeship predicted this but I was sceptical.





Each strake has two coats of epoxy sanded to 120 on both sides. A lot easier to do it flat on the bench than chasing the inevitable runs from epoxy coating vertical surfaces. Slow going, though, as each pair of planks took almost a week to cut, finish and install. The two batten, hot glued stick method (see post #20) to pick up the strake patterns worked great. Much easier than making luaun patterns for each strake as I did on the Arctic Tern.

On to laminating a 1/4" layer of Sapele to the transom today.

[Figment]

Slow going?
If one subscribes to the "perfection IS speed" school of thought, you're zooming.
I love it.

[mcdenny]

The boat building progress had been pitifully slow of late but I can show you the final layer of 1/4" Sapele laminated onto the transom. The grain match is not that great but it is better than it looks in this flash photo. I saved the better stock for the deck.



I've also got the outer stem and keel on and about half of the epoxy fillet sanded smooth (kinda). My son is visiting this week so I'm hoping to get the xynole on the bottom with his help.

Here's why the boat progress is so slow.


We got a little travel trailer 3 weeks ago and of course, even though it's brand new, I have to redo the electrical system, rebuild the beds and add a closet. The boat is pretty much on hold until I get the trailer done.

[freshtrax]

I love this boat. I think it would make an awesome great lakes boat for down riggin for trout and salmon. How much hp are you planning on punning on her?

[mcdenny]

It is for the Great Lakes, at least for the St Clair river part. She will have a 60 hp Evinrude ETEC engine. Since it is a two cyl design the power head is relatively low and will fit entirely under the flush aft deck. 60 hp should give about 30 mph at WOT.

Someone here posted data recently about his Atkin Ninigret, very similar in size and shape to my boat and about 300 lbs heavier. He reported 32 mph with the 60 hp ETEC.

Denny Wolfe

[skaraborgcraft]

Looking good Denny,transom looks fine.Keep at it. Cheers

[P.L.Lenihan]

Glad to see the fine work done so far,Denny. At the rate you plow through the boat work, the trailer must be all done by now surely. Looking forward to your return toward the work left on the boat.



Cheers!

Peter

[mcdenny]

Thanks, Peter, but building cabinets in the trailer is a lot like fitting the interior in a boat, everything but the floor curves in three dimensions and it's only sorta symmetrical. Bottom line, it seems to take forever to make much apparent progress. Sadly the boat has become a shelf to pile trailer crap on.

Denny Wolfe

[P.L.Lenihan]

Fair enough Denny. I've no doubt your thread followers will be patient and eagerly await the sweet conclusion to this fine boat. Good luck with the trailer!


Cheers!



Peter

[LakeErieSailor]

Hi, Denny

Very interesting boat and very nice work. Since you mentioned Lake St. Clair, I'm assuming you're somewhere north of Detroit (I grew up in the former East Detroit, now laughingly called "East Pointe"), but I'm down here in the southeast corner of the state, in Monroe, renovating a Folkboat.

Your trailer interests me; could you tell me who the manufacturer is, dimensions, and most important to the female of the combo, if it has a head?

Thanks.