Lee wants a new trimaran design...

[NeilMB]

Why the second leeboard? Mine works equally well on both tacks despite being on one side of the boat. There are lots of successful designs using off-centerboards with no practical problems with the asymmetry.

Here’s one Jim Michalak article on leeboards http://www.jimsboats.com/15sep22.htm and another one about the guards and pivots that make it work http://www.jimsboats.com/webarchives/1998/15jun98.htm

[Lee.007]

With my current trimaran, it sails differently on each tack. Granted it is a kayak turned sailing trimaran, but sometimes I have to haul in or let out the main sheet to get the same speed on each tack, and I can't point exactly the same on each tack either. I am sure the leeboard is not the only thing affecting this, but I wanted to make everything the same for each tack so the only thing I have to do when I tack is raise one and drop the other. I am also going to make one side convex, and angle them slightly toward the bow to help counter leeway and maybe point higher too. With current trimaran I can only get slow speeds when pointing high, but I can still move. I want to go fast pointing high. Right now my max speed is 60 deg offwind with my kayak trimaran. I will check out your links though. Thanks!

By the way everybody, I think I am going to make the hull a bit more shallow than my latest change. I added 4 inches to the bottom of the hull to allow me to put a 4 inch radius on the bilges. But I think I am just going to take that back down to about a 1 inch addition and see if I still keep my original displacement. I am losing a little bit of volume by adding a radius to the bilge corners, so thats why I had to add a little to the bottom. Only thing I am worried about is if it is going to sit too high, and my amas won't keep me from flopping back and forth in flat water with little wind.

[Lee.007]

Lee -- I think you're right in going with the Hobie 14 sail, with the option of adding a jib. In fact, in light airs you'll want an even bigger headsail, but that's a better option than dealing with an overly tall mast all the time. As you have the boat drawn now, you could very easily fit a bowsprit and fly a sizable asymmetrical spinnaker or similar.

I traced the Hobie 16 rig and scaled it down to size in autocad. Looks like its going to fit right on my boat (see the pics below). I won't need to add a bowsprit. I have enough room to fly the jib anchoring the forestay at the bow, or move the forestay back a little and fly it like a genoa. I plan to rig it for both options and see which one works best.

I also redesigned the hull shape with a 3" radius on the bilges, and added 1" of depth to the floor. My hull displacement at the water line is now 867 pounds. That's right at the target I was shooting for from the beginning. When I lengthened the Amas that gave me 664 pounds of buoyancy in the amas. Less than what I would like, but I moved them out a little bit more to give me more righting torque. But I don't want to make them any bigger or less efficient. I will just have to sail in some heavy winds and see what it takes to sink them so I will know when its time to reef or dump air.

So I am calling the hull and ama design good for now. I will design the rudder, maybe tweek the leeboard a bit, and then it is going to be time to start cutting wood!!

New Hull transom.jpg

New Hull Bermuda Rig.jpg

New Hull Sloop Rig.jpg

[mattglynn]

What is your building process going to be? You could build it upside down on a strongback with temp frames, attach the large flat panels for the three sides and then strip the chine radius.

867 pounds sounds about right, I think you'll probably end up over 300lbs ready to sail with the rig, so say 400-500lbs carrying capacity, thats enough for two average adults plus some gear.

[Lee.007]

What is your building process going to be? You could build it upside down on a strongback with temp frames, attach the large flat panels for the three sides and then strip the chine radius.

867 pounds sounds about right, I think you'll probably end up over 300lbs ready to sail with the rig, so say 400-500lbs carrying capacity, thats enough for two average adults plus some gear.

I am debating that exactly. strong back with temp frames, then add bulkheads later... strip the chine radius and glass later... etc.

I think I am going to keep the amas with hard chines so I can use flat panels all around, almost like a stitch and glue, but I want to keep the bulkheads inside of it to keep the form straight. This is because I haven't figured out how to make autocad unfold a 3d panel without adding an expensive plugin to the software. Without doing that, it is a pure guess what the dimensions need to be on a multi-curved surface.

I probably will do like you suggest and use flat panels for the flat sides of the Vaka, but use strips on the Vaka chines. I had thought about doing this earlier, but I was just trying to eliminate as many steps as I could. If I use as many flat panels as I can, I could probably build the chine radii out of strips first, glass them on the inside, and then reattach them as I attach the pre-glassed (on the inside) flat panels. Then the temp frames become permanent bulkheads, the inside is already glassed, the bulkheads get a coat of epoxy, the exterior gets a coat of glass and a coat or three of epoxy, and that's that for the Vaka hull panels.

I am going to read Goudgeon's book again and see if I can pick up any more ideas to make this go faster. I have been delayed due to holidays and I have GOT to get busy cutting wood!!

[mattglynn]

Im not sure I understand the issue with the ama's, but if your software can give you the measurement over the curved surface just start at one end measure over then down and repeat for 10 or so points along hull, layout the points off a straight line(like a factory plywood edge) and use a batten to connect them and create a fair keel line. You don't have much sheer in your amas so measuring off the same straight line come 1" or 1 1/2" down at the deepest part of the sheer and maybe half that measurement at the transom to avoid the banana look. A scale model out of cardboard would be a quick and dirty way to double check everything. Probably not a bad idea to keep the bulkheads in where the aka's attach to the amas.

I'm not sure stripping and fiberglassing the chines first would save you that much time, if they come off and get re-installed without getting warped you're still flipping the boat 3 times instead of once. You're probably going to want to glass tape in inside seam anyways, so might as well just do the whole interior in one shot and not have any unsightly seams to worry about.

[upchurchmr]

Depending on the radius of the chine that you want you might use the technique that Searunners have used for 40 - 50 years.
Cut the side panels and the bottom panel such that the inside corner of each panel are touching.
Mix a batch of epoxy/filler and use it to make a fillet on the inside of the side to bottom joint. Round the outside of the plywood until you get that inside joint to where there is nothing but the two corners left.
Glass the inside (lapping over the plywood, fillet, and the other plywood) joint. Glass the outside of the joint .
Now you have a rounded external joint. The joint has lots of strength since the ply and fillet form the inside of a sandwich.

Searunners have sailed lots and lots of miles.

The only limit is that the radius is relatively small.

You ought to do a test to see what you can achieve. You don't need marine ply to do the test.

[Woxbox]

Depending on the radius of the chine that you want you might use the technique that Searunners have used for 40 - 50 years.
Cut the side panels and the bottom panel such that the inside corner of each panel are touching.
Mix a batch of epoxy/filler and use it to make a fillet on the inside of the side to bottom joint. Round the outside of the plywood until you get that inside joint to where there is nothing but the two corners left.
Glass the inside (lapping over the plywood, fillet, and the other plywood) joint. Glass the outside of the joint .
Now you have a rounded external joint. The joint has lots of strength since the ply and fillet form the inside of a sandwich.

Searunners have sailed lots and lots of miles.

The only limit is that the radius is relatively small.

You ought to do a test to see what you can achieve. You don't need marine ply to do the test.

True enough, but keep in mind the Searunners (I had one) were built of ply and painted. After grinding down the chine and reinforcing it with layers of tape and glass to get that soft curve, it needs to be painted. Lee is looking for a hansom, bright-finished hansom boat.

[upchurchmr]

Forgot about the bright finish. Since I've decided to never do that again.

Thanks for pointing that out.

[mattglynn]

That’s basically what the plans said to do on my seaclipper, but it uses a chine log instead of a fillet/glass. I suppose the chine log method could work as once it is shaped only wood is exposed for the bright finish, you just wouldn’t be able to fix any mistakes with fairing compound.

[upchurchmr]

The real problem with the seaclipper or searunner idea is the rounded off edge of the ply.
That looks really bad when finished bright - It was just a really bad suggestion on my part.

[Lee.007]

mattglynn - I thought about using several small straight lines to approximate the length of the curved gunwales, but I figured an easier way would be to build up the frame - chine log - shear clamp skeleton. Then tape several large pieces of cardboard together to get one continuous piece. Tape that continuous piece of cardboard up to the skeleton and mark it along the mating edges with the chine logs and the shear clamps. Then I have a pretty accurate pattern of what the sides need to be. Now, after I get some accurate measurements of the profile for future documentation, I will lay the cardboard down on a 20 foot long bench I am going to build, tape it down nice and secure, cover it with clear plastic, and build the strip side panels directly over it. This will allow me to align the strips so they are parallel with the shear clamp. I think this will look a lot better than building rectangle panels where the strips land sort of randomly, and then they strips may be cut a way not as appealing to the eye as flowing strips that are parallels to the shear clamp.

I could also just look at the side profile in my cad and divide the profile into sections and loft it from that. Or maybe not since it is angled with a little v shape and not straight up and down on the sides.

Marc - Yeah, I am going to do bright finish. I am going to have chine logs (1/2" x 1") where the sides meet the bottom at the start of the radius, and I also plan to put a keel log (1/2" x 1/2") down the center. Another "log" (1/2" x 1 1/2") down the middle of the sides halfway between the shear clamp and the start of the radius, and then the shear clamps (1" x 1 1/2"). Might be overkill for strength and rigidity, but I don't think the added weight will be significant enough to make a difference. But the logs won't be big enough for me to make a 3" radius out of them, so I figure I will just strip the radius before or after I build the sides, and cover the insides of the radius with 4oz glass. I am probably adding more work than I need to, and if I decide to make this a permanent "sellable" boat design, I will probably look into finding some shoe molding (quarter round) that has a 3" radius. Matter of fact, now that I am thinking about it, that would give me a nice shelf to attach stuff to the inside of the boat. I could build a little raise floor so I don't get my feet wet if water gets into the boat. Thanks for sparking the idea guys! I am going to look for some shoe molding to see if I can put it in this one I am building. I might have issues bending it along the rocker though. We will see.

[Lee.007]

A real quick search of the interwebs shows that I would have to order custom made quarter round, and its gonna be cost prohibitive. I will just strip the radii.

[mattglynn]

That sounds like a better strategy for getting the hull panel dimensions, especially if you have a helper available. It might be better to use a more rigid non-corrugated cardboard, if there is too much deflection between frames it could add up over 18', although with your build technique it wouldn't be to hard to "trim to fit".

The scantlings for your keelson might be a little light, and your stringer between the sheer and the radius chine might be too tick and really hard to bend into shape, or you could probably just get rid of the stringers if you used S-glass instead of E-glass, it also has better impact resistance which is the main issue with strip boats.

If you had a bit more freeboard you could put in a cockpit sole above the waterline to make it self draining and have a buoyancy chamber underneath.

[Lee.007]

That sounds like a better strategy for getting the hull panel dimensions, especially if you have a helper available. It might be better to use a more rigid non-corrugated cardboard, if there is too much deflection between frames it could add up over 18', although with your build technique it wouldn't be to hard to "trim to fit".

I do have a few helpers. They call themselves "dad's indentured servants" from time to time, but I call them children. Don't know if I can find non-corrugated. I can get 2 feet x 5 feet sheets from staples for fairly cheap.

The scantlings for your keelson might be a little light, and your stringer between the sheer and the radius chine might be too tick and really hard to bend into shape, or you could probably just get rid of the stringers if you used S-glass instead of E-glass, it also has better impact resistance which is the main issue with strip boats.

I think you may be right about my keelson. I might increase it to 1" x 1/2". its also really easy to reduce the stringer on the sides to 3/4" x 1/2" too. I don't think I will need them for strength since I am going to make the hull out of 1/4" thick strips, and sandwich it inside and out with 4 oz fiberglass with at least 2 coats of epoxy.

If you had a bit more freeboard you could put in a cockpit sole above the waterline to make it self draining and have a buoyancy chamber underneath.

Dry feet would be really nice. I might make at least a slightly raised sole to keep the water out of my toes. (fungus tends to grow there when it stays damp!)

[Lee.007]

Well guys, I just had a near death experience. Not really, but it felt like it. I was trying to open my autocad to continue drawing the individual parts I need to make for my new trimaran design, and autocad said my file needed to be recovered. No problem, I thought, this happens a lot when you have a big file in autocad. Then autocad said "drawing file not recoverable". Hours of work. Hundreds of hours of work. All lost. I tried to restore the back up file. Not recoverable. I was about to give up all hope when I decided to change the backup file, .bak, to a drawing file, .dwg. It was pretty corrupt and windows 10 would not let me change the file extension from file explorer. So, its a good thing I know a thing or two. I started a cmd prompt. I used the dos command RENAME from the command line and renamed the back up file to a different name completely and added the .dwg extension. Victory! That worked. The renamed backup file loaded up perfectly. After taking a valium or three to calm my racing nerves, I saved that freaking drawing about 5 times in different drives.

So it wasn't really a near death experience, but it sure felt like it. If there are any of you out there drawing stuff up on the computer, learn from my mistakes and make tons of backups!!

[mattglynn]

That sounds stressful, good thinking on the command prompt rename. I recently knocked over my wife's backup hard drive while vacuuming and just about had a heart attack.

Here are some articles that might be interesting as you move away from designing the hulls to the appendages.

https://www.storerboatplans.com/boat...erbox-sailing/

https://www.storerboatplans.com/foil...s-it-possible/

[Lee.007]

Thanks for the links Matt! That's good stuff.

Calling All Naval Architects:

I am stressing about something that I probably shouldn't stress over. The ama bulkheads. Other designs I have seen have them spaced about 2 feet or more apart from bow to stern. My engineering mind says, "thats not enough". Cause when you build houses you put the studs in the walls at 16" on center. So I put extra bulkheads in the amas and made them 16" on center. Then I got to thinking, is the small amount of extra weight really going to give me that much more strength? Maybe I don't need them after all.

So help me out here and keep me out of the nervous hospital, what do you guys think? I have not cut anything out of wood yet so I am not going to waste any material. What is a good rule of thumb for bulkhead spacing in ama hulls, or any hulls for that matter??

[Lee.007]

Another naval architect question:

Which is better, making the leeboard flat on one side and convex on the other to counter leeway, or canting it 4 to 5 degrees to counter leeway? In my mind I am thinking canting it 4 to 5 degrees will cause drag that I don't want, but I also wonder if 4 or 5 degrees will cause enough drag to make a difference. Does anybody know if a leeboard with one side convex and one side flat will cause any drag? Or would doing both canting it and making one side convex be a good idea?

EDIT: I think I may have answered my question with this: http://airfoiltools.com/airfoil/deta...il=naca2408-il . I aint no aerospace engineer, but if I understand the plots under the airfoil shape pictured on this website, a convex shape, angled at 4 degrees gives me the maximum lift / drag ratio. But, I ain't trying to get airborne, and for planes I guess they can accept some drag if they get high enough lift / drag ratio. All I am trying to do is counter leeway. I guess its a tradeoff. If I want to point higher and counter leeway, I have to accept some induced drag.

[Lee.007]

Where are all those naval architects at?

Anyway, I have another question for the group, can I get away with less leeboard surface area on a multihull compared to a monohull? I sized my leeboards at 2.75% of the min sail area and I am still at around 5 sq ft. I only found a mention in the Professional Boat Builder magazine from Dec-Jan 2006 that says monohulls can use less, but it didn't say how much less. The 5 square feet leeboard works out to 3 feet by 20inches in the water, and sticks up higher than the gunwales by about 4 inches. This will prevent me from doing any hiking on the windward side if I have two leeboards. Any ideas??

[Woxbox]

Hi Lee,
Glad to see you're still working hard on the calculations. It's not really safe to compare airplanes with sailboats. Keep in mind that the forces on a sail push the boat sideways a bit as it moves forward a lot. This automatically induces an angle of attack on the keel, leeboard, daggerboard, whatever foil is down there. If you add more angle there's a high risk of getting too much, which will bring on loss of lift, massive drag and stalling. (OK, that part is like an airplane.) The traditional Dutch leeboard boats have both toe-in and asymmetric shape, but they are slow boats in canals where control is more important than speed. If it were my boat, I'd make the boards symmetrical and parallel to the centerline. For one thing, if they're asymmetric or if they have any toe-in and you leave them both down while short tacking, they'll be fighting each other.

As far as area, the faster you go, the less area you need. I can't give you a number or ratio, but reviewing successful designs of the type you are making is, I think, a better route than taking a formula that's an average for all types of sailboats. That Weta graphic I posted earlier, for example. You can easily figure out the scale and get an area. Aggressive sailors with daggerboards adjust the depth all the time to suit conditions. There's no magic number.

[mattglynn]

In response to your question about bulkhead spacing. https://www.westsystem.com/wp-conten...k-061205-1.pdf Start at page 265. Bulkheads every 16" is way too many. If I remember correctly you're using 1/4" strips with 4oz glass both sides. You're going to have an epoxy fillet/glass joint along the keel, the ama sides will be slightly tortured into shape, and I would assume that you have a deck stringer. Your ama sides are probably around 18" at the deepest point right? For the sake of not dragging this out with too much math you're probably safe putting in a bulkhead at two the connection points with the akas, and you can overkill it by putting a ring frame in the middle between the two aka connection points.

As far as foils go, assuming you're asking about canting in the vertical plane, canting a couple of degrees is really going to do anything, you're going to heel anyways. As far as asymmetry goes, if it worked we would see it more often on catamarans, or trimarans with a board in each ama. As far as I understand asymmetrical foils with one flat side don't generate significant amount of lift unless they are almost horizontal.

For size I think the rule of thumb is something like 4-5% of sail area, But you could always build them oversize and cut them down until its just right

[Lee.007]

So, I have been working a lot lately at my real job. Too many dumb people in the world not wanting to be peaceful. Not a lot of time to work on my boat. I do have a plan to get my son's jeep out of the garage, and hope to do that tomorrow and start cutting some bulkhead frames.

Thanks for the advice and the book reference Matt. I have that book, actually I have had it for about a year and half now. One of these days when I grow up and retire I might have the time to sit down and read it all the way through. Not sure I explained turning the leeboard correctly. I don't want to try to counter heeling. I want to try and counter leeway, and point higher. If you were standing in the boat looking straight down on the leeboard, i want to rotate it on the leading edge axis about 4 degrees to windward.

I think I am going to have to experiment with the board size. Dave had a good suggestion to make the board position adjustable fore and aft and fine the sweet spot. Maybe I should do that also with depth, area, and angle of attack.

I would really hate to make my boat draft 4 feet if I don't have to. I could just see myself running aground on that one random rock at the top of an underwater mountain just after I hit my record setting speed. But of course I am making it able to kick up if I hit something. I just don't want to have to worry about it being that deep though. I don't want to make it wider either and increase the drag. I am going to have to stop fretting and start building.

[Lee.007]

Ok, the jeep is out of my boat factory (garage), I am done drawing, hopefully my next post will have pictures of some sort of boat assembly. Till then, here are some pics of my final design. Let me know what y'all think:

Starboard ISO view.jpg
Port ISO view.jpg
FinalSideview.jpg
Rudder Details.jpg
Leeboard Details.jpg

[Lee.007]

This is the beginning of the beginning. Design all done. Benches built to support the boat as I build it. Drawing frames on plywood now to cut out the bulkheads and form the skeleton!
20230214_194657.jpg

20230214_195914.jpg

[Woxbox]

All right, Lee! I'll fire up the popcorn machine.

[Lee.007]

Woot Woot! Since the military gets a 4-day weekend for Presidents Day Holiday, I got a little over a third of the frames / bulkheads drawn on the plywood and cut out yesterday. By the way, I have no idea why the forum website rotates some of my pics 90deg when I upload them. Sorry if it makes yall turn your neck sideways.I bought myself some mechanical drawing tools from amazon. Even though I design my stuff in AutoCAD, the mechanical drawing I was taught in college helps make some pretty accurate parts. Having a compass and T-square in my hands again made me feel like I was back in school re-living my glory days!20230217_150733.jpgThis is what I stressed waaaaaayy too much about. Putting the radii on the corners of the bulkhead, which is basically going to form the "bilges" was driving me crazy trying to make the 3" radius line up with my AutoCAD generated center of the radius. I kept telling myself that my accuracy can only be +- 1/16" with a ruler and a tape measure, and a 1/16" isn't going to make much difference on a 20 foot boat. It aint like I am building a space shuttle to go to the moon. I am just building a boat. So I just ignored the CAD generated centers and used my compass to scribe a radius to fit the the lines that were drawn. My favorite quote from Nick Schade, "A wooden boat will soak up every bit of perfection you can throw at it. Learn to pick your battles."Radii.jpgAn honest days work:DaysWork.jpgTime start on the next sheet of plywood now!!DrawingFrames2.jpg

[Lee.007]

Its pretty cold in GA today. Thoguht I would show how I keep everything square while transfering drawings to the plywood. Its simple. I just use a 48" sheet rock (aka drywall, wall board) square to layout the outer edges of the frame. The 1/4" luan i am using for the frames /bulkheads is cut pretty square from the factory, so i use the factory edge as my reference line for the dimensions:

20230218_123919.jpg

[mattglynn]

Hell yeah Lee! Good luck, its nice to see you making some sawdust. Love the quote as well

[Lee.007]

I am glad I am finally making sawdust too! All this saw dust just might make a boat in a few months! I really am glad to finally be cutting some wood up.

So to cut out the middle sections of the frames, I first started using a hole saw in my battery powered hand drill to make a hole, and then go at it with a jigsaw. I felt like that was too difficult, so I switched to my Dremel multitool with the drywall jam blade on it. Thing is about those multi-tool saw blades, unless you have your wood secured down so it cant vibrate, the blade just grabs it instead of cutting it and the friction makes it start to smoke. I think I will go back to the jigsaw tomorrow. Today I got some more drawing and cutting done. I am about 70% finished with all the bulkhead frames.

So my build process is going to go like this: First I am going to build the vaka skeleton/frame with the bulkheads and stringers. Then I will use a long piece of cardboard taped together from smaller pieces to create a pattern for the side panels. I will use that pattern to make glued strip panels flat on the bench. Once I get them sanded, I will lay 4oz fiberglass over them and one coat of epoxy. I will make them maybe an inch oversized so I can cut them to fit perfectly on the vaka hull. same for the bottom. I am going to experiment and see if a panel will be flexible enough to bend around the bilges, but if not, I will figure a way to just strip the bilges on the hull instead of making panels. I am going to use the same process for the amas. I think I might be able to get the last 30% of the frames drawn on the plywood tomorrow, and finish cutting everything out. I can't wait to line up the frames and put the sides, bilges, and bottom on the vaka!!

[Lee.007]

So I had a very productive weekend, and got some work done tonight too. I have all the bulkhead frames cut out for the amas and the vaka and and today I lined up, squared, and levelled the benches. Screwed them together, and glued some shims under the legs. Then I snapped a chalk line down the middle to use as a general guide, measured the distances and marked the stations, and then I mounted a laser to my bench. I used the laser to keep the bulkhead frames centered. I had the good sense to draw centerlines on my bulkhead frames, so when I fixed them to the bench, all I had to do was line up the laser with the bulkhead center line and screw it down. I have some pics below showing this. Made it super easy to keep everything lined up. I also squared some lines perpendicular to the keel and drew them on the bench at each station so I could keep the bulkheads squared laterally. I was able to get all the Vaka bulkheads fixed to the benches tonight.

Since this design is pretty much all my own now, I am going to call it the Creekwater 20. Not sure what I will name the boat when I finish it. The drifter and the slingshot gave me some ideas, but none of the dimensions are the same, the leeboard design is different, the rudder design is different, and the amas are different.

Here she is without her clothes (I haven't made her cedar dress yet):
20230221_214914.jpg

This is what I was talking about when I said I used a laser to line it up. I have a Bosche wall tile laser that I used. I anchored it at the stem, and put my bulkhead frames on starting at the transom and working my way forward in sequence so I would block the laser by putting number 1 frame in front of all the others:
20230221_205607.jpg
Laser alignment.jpg


Oh yeah, check this out. Can you see what's wrong with this picture???? ( answer below )

20230221_201836.jpg

Answer: The freaking transom is angled to aft, instead of forward. I guess that was my drunken pirate moment. But in my defense, I am building this hull upside down so it looked right according to my drawings that were right side up. I just forgot that the hull is upside down. I had to take it loose and redo it.

[Lee.007]

Inventing new profanity and PL Premium....

So last night I was scarfing my keelson together to apply to the bulkhead frames. My wife asked me to come up for supper and a movie, and so I was quickly putting away tools, cleaning up, and I had just finished the last scarf joint. I had the keelson laying on top of the frames. Unbeknownst to me, the end of it was sticking out beyond the path of the garage door. I closed the garage door, and the keelson was caught by the door, nearly snapped it in half, but I caught it before total destruction and reversed the door. However, my perfectly made scarf joint was ruined. I taped it back together in position and I guess I will see how the glue set over night. This is when I invented new profanity.

I am experimenting with PL Premium. Seems to glue pretty nice, just as good as epoxy. But it cant replace epoxy for the hole thing I think. Anybody else have experience with pl premium??

[Lee.007]

Ok, so, last night I got all but one of the side stringers attached to the bulkhead frames. She is really starting to take shape now. I made the stringers out of SPF 2x4's from lowes, and I had to scarf out a lot of knots. You just can't find decent wood nowadays. I picked through them to get the spruce instead of the pine so it would be a little lighter and the spruce usually has less knots, but not this time. I keep experimenting with the best way to make scarf joints. Cutting and matching up the angles isn't that hard, its the clamping and securing it while the glue dries that gets me. I drilled some pilot holes and ran a sheetrock screw through them to hold them tight, and it does a good job, but there is a fine line between tight enough and too tight and I cracked the wood too many times doing that. I don't clamp them on tables like a lot of people do. I put the stringers on the boat frame, cut the scarf joint, and glue it in place on the boat. That way I don't have to wait on the scarf joints to set before I can put the stringer on the boat.

I did some more research on PL Premium. The data sheets from locktite and another company in Canada said "waterproof". But then in the limitations both of them said, "not for marine use" and "not for use in submersible applications". Well, if it is waterproof, then why not??? Anyway, just like using wood glue, its going to be covered and sealed under epoxy and fiberglass, so I ain't worried about it. I plan to run a fillet of thickened epoxy and fiberglass tape down the sides of the stringers once I have the hull sides attached, so it should be sealed from water. I might be going a little overkill with the fillets down the sides, but I want this boat to last forever so I am making it as beefy as my expected weight limits will allow. I don't want the boat itself to be more than about 150 pounds, 200 pounds max, so I can push it around on the trailer if I have to. Makes for easy beaching too.

I will try to post some pictures tonight when I get home. I had to work today on battle captain duty so I won't get any work done on my boat.

[mattglynn]

Looking pretty good Lee. How many of those frames are you going to keep in the hull?

I mentioned a couple pages back that my father-in-law has experimenting with PL premium for years. It seems to hold up well in "Marine" applications as long as there is enough clamping pressure. It doesn't work on treated lumber.

With that many scarfs in your stringers have you double checked that you're getting a fair curve without too many flat spots? Adding fiberglass tape on the stringers is just an expensive way to add weight.

I always found it faster and easier to glue all my stringers for the project at once on a big table, and then install as needed. But everyone's shop space/work schedule is different.

You could use a wooden dowel or biscuit to keep the pieces from sliding and then use clamps for the pressure

[Lee.007]

Here are some more pics. I have finished the vaka frame.

I plan on keeping all the frames Matt, but I am going to cut them down considerably once I get the sides of the hull glued on and covered with fiberglass and epoxy. Obviously the sections of the frame going athwartships will completely cut out to allow room for passengers, gear, etc. Except for areas where I need support for decking in the bow and stern, and around the mast. Oh, and I made sure the scarfs didn't make me flatten. But if they did, I would glue some more wood on them and sand it down to a fair curve. I do think it is probably faster to make the scarfs ahead of time as far as getting them to set. But I am always in a rush and I figured I would just let them cure on the frames.

Oh yeah Matt, I almost forgot. The PL Premium held just fine except in areas like you said where there was not enough clamping pressure. I only had 4 breaks. They were all at the transom because of the pretty extreme curves I am putting on the bilge stringers at that point. But, the wood separated. Not the glue. So I can't blame the glue. As long as she was sitting still, everything was fine, but when I picked her up to carry her back into the garage after taking the pics below, the transom popped loose. I was letting her wobble too much and it strained the joints. She is pretty rickety in this stage without any sides on her. So I sanded off the bits of wood and glue that were left in the breaks, re-applied glue, and ran a sheet rock screw in from the back to hold some clamping pressure. I am going to leave the screws in until I get the sides on and fiberglassed on the outside, just to be safe. And I meant to say the stringers will have a fillet of thickened epoxy, and the seams between the sides and the bottom will be taped.

I am working on my vaka side panels now. I stapled a long piece of cardboard made from disassembled cardboard boxes to the side and traced a pattern to give me a rough outline of the area I need my cedar strips to cover. Once I get the sides on and trimmed to fit as perfectly as possible, I plan to lay them on the bench, square them some how, and make measurements so I can reproduce them on future boats if I plan to build some to sell. I am about 70% done with the first vaka side panel. It is a lot of labor to make strip panels, but I think the gorgeous look is definitely worth it. With the blend of the western red cedar mixed with the white cedar, its kind of a camouflaged pattern. On my current boat, you can't see me from the water when I am beached until you get within about 75 yards of me if my sail is doused. I have also silently slipped around a point and into a cove and surprised some teenage lovers more than once . If I am hugging the lake shoreline, its hard to see me without my sail.

Here she is with the stringers installed. The tops of these frames have a large section athwartships, but almost all of those will be cut out with just the "ribs" left.
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So this isn't the straightest keel I guess, but its close enough. Oh, and one of my favorite Army mentors told me once, "Perfection is the enemy of good enough".
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I took her off the bench and let her sit on the driveway outside to get some air, and see what she looks like right side up. In this picture, the bow looks like it has a lot more forward rake that what it really does. I don't particularly like a lot of forward rake. I think if you need that much deck space, you may as well stretch the overall length and give yourself a faster hull speed, unless wetted surface area friction is going to be a huge concern for some reason. It also gives you more buoyancy up front too.
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See how the western red cedar and white cedar sections blend with the clay beaches at Strom Thurmond Lake on my current boat I built two years ago?
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I will post some more pictures once I get the sides done and cut to fit.