Michael's ZIP

Outboard designs up to 14'

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hoodman
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Re: Michael's ZIP

Post by hoodman » Sat Jul 28, 2018 11:27 am

I made a little scarf sled for my table saw that you clamp a board into. Works fine for anything 3" wide or less.
Matt

Building a Geronimo......!
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mrintense
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Re: Michael's ZIP

Post by mrintense » Sat Jul 28, 2018 12:25 pm

Michael,

I made to small wedges at the angle I needed using my table saw, then attached them to a piece of plywood. Sandwich the board between them and then use your router to cut the scarf joint. The wedges can be moved move different widths.

I think that you should consider the scarf over the lap joint as there is no mention of a lap joint being suitable for that type of join. Besides which you'll always wonder about it. :)
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Carl
a.k.a. Clipper

Crafting a classically styled Vera Cruise named "Some Other Time"

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BarnacleMike
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Re: Michael's ZIP

Post by BarnacleMike » Sun Jul 29, 2018 9:47 am

Carl,

I like your router jig! Very clever, and I can see that it would be very useful.

I found a nice discussion about scarf joints vs half-laps on the LumberJocks.com forum. Here's the link if you're interested: http://lumberjocks.com/topics/30026 I'll post a screenshot of the gist of it.

I think there's little doubt that the scarf joint is stronger. My thinking is: just because the scarf joint is stronger, doesn't mean the half-lap is weak. The question then becomes whether or not the half-lap is adequately strong to do what I'm asking of it. I think it is in this case.

So, why not just play it safe and use the scarf joint anyway? In this case, it's merely the convenience of what I've got to work with in my shop. I figured it would be easier to clamp the boards to my work bench, and use the router to cut away a lap joint. It seemed that way, at least, until I actually did it... but that's another story lol. :)

After several attempts, I finally got the half-laps "right." The epoxy is curing now, and I'll unclamp them tomorrow. If I don't have confidence in the half lap, I can change it.

I think the big comparative weakness for the half lap joint is in bending. However, these will be in the aft section of the floor, where it is flat. I'm also planning to back both joints with plywood, so they'll be "sandwiched" between the hull and the backing plate. If the hull bends enough to break those joints.... I'll be in some rough water indeed.
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-Michael

"How long does it take to build a boat? Until it's finished" — yours truly

Blog (Utility & Zip): http://barnaclemikeboats.blogspot.com/
Website of Boat Photos: https://michaelsmaddox.wordpress.com

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hoodman
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Re: Michael's ZIP

Post by hoodman » Sun Jul 29, 2018 10:14 am

How are you doing your other longitudinals? Full lenth pieces?
Matt

Building a Geronimo......!
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BarnacleMike
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Re: Michael's ZIP

Post by BarnacleMike » Sun Jul 29, 2018 10:22 am

As much as possible, yes.

The floor batten structure is like this:
  • Keel is laminated, with a reinforced butt joint 32" forward of the transom. Other butt joint is approximately 6' forward of the transom.
  • All 3 port side battens are solid (full-length).
  • The inner and middle starboard battens are joined.
  • The outer starboard batten is solid (full-length).
I'm planning to laminate the sheers and chines, with butt joints as needed (similar to the keel).
-Michael

"How long does it take to build a boat? Until it's finished" — yours truly

Blog (Utility & Zip): http://barnaclemikeboats.blogspot.com/
Website of Boat Photos: https://michaelsmaddox.wordpress.com

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Re: Michael's ZIP

Post by BarnacleMike » Mon Aug 06, 2018 5:59 am

The half-lap joints turned out to be very strong. I'm still not finished, though. The boards are rough-cut 4/4 mahogany, so now I'm in the process of sanding them. From there, I'll laminate a piece of 1/4" plywood onto the top to reinforce the joint. I'm thinking a 16-18" strip should work. (The lap is 4").

I was also reading in the Glen-L book about battens. Glen doesn't mention extending battens, but he does discuss a few ways to reinforce them. One is to laminate a piece of plywood to the inboard side of the batten. The plywood would extend the full length between frames, running as high as the floor members of the frames. Then, a wood strip is laminated to the side of the plywood, even with its top-side edge. This both supports the rigidity of the battens and also provides support for a floor.

I'm giving that option some consideration. It would be perfect if I decide on a simple plywood floor.
-Michael

"How long does it take to build a boat? Until it's finished" — yours truly

Blog (Utility & Zip): http://barnaclemikeboats.blogspot.com/
Website of Boat Photos: https://michaelsmaddox.wordpress.com

Stevel
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Re: Michael's ZIP

Post by Stevel » Mon Aug 06, 2018 7:45 pm

Michael , do you joint and plane the rough mahogany ? I am not sure how needed it is that it’s perfectly flat .. I’m so used to building furniture where the lumber needs to be 100 percent square and 90 degree faces..

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Re: Michael's ZIP

Post by BarnacleMike » Tue Aug 07, 2018 7:53 am

Stevel wrote:Michael , do you joint and plane the rough mahogany ?
I did in this case, anyway. I just want to get the topside surface smooth before adding a 2 x 18ish plywood backing "plate" over the joined area.

I don't mind working with the rough-cut lumber. I usually just get what's available at the lumber yard. Sometimes it's planed, or sometimes just planed on one side. The last couple I've bought were rough-cut.
-Michael

"How long does it take to build a boat? Until it's finished" — yours truly

Blog (Utility & Zip): http://barnaclemikeboats.blogspot.com/
Website of Boat Photos: https://michaelsmaddox.wordpress.com

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Re: Michael's ZIP

Post by BarnacleMike » Fri Aug 10, 2018 7:19 pm

Finally got the rough-cut wood sanded down enough to make the half-lap joint photogenic.

I cut the plywood backing for both battens today, also. I cut it from 3-ply Douglas Fir marine plywood (1/4") rather than the 5-layer Meranti of the same thickness. The Douglas Fir seems to be MUCH more rigid, and better suited for this type of thing.
Attachments
IMG_6897.jpg
IMG_4699.jpg
-Michael

"How long does it take to build a boat? Until it's finished" — yours truly

Blog (Utility & Zip): http://barnaclemikeboats.blogspot.com/
Website of Boat Photos: https://michaelsmaddox.wordpress.com

Hercdrvr
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Re: Michael's ZIP

Post by Hercdrvr » Fri Aug 10, 2018 7:39 pm

Good attention to detail. Dont forget all the lap jointed battens get a full length 1/4” plywood butt block too, the bottom planking. After what I’ve put my Squirt through, I think you’re good.
Looking great Sir,
Matt B

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BarnacleMike
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Re: Michael's ZIP

Post by BarnacleMike » Sun Aug 12, 2018 6:21 pm

Thanks, Matt!

I got the topside butt blocks epoxied on today. They're longer than originally planned... 23-1/4 inches. It's all clamped up and curing right now. I didn't use any screws. Thickened epoxy only.
-Michael

"How long does it take to build a boat? Until it's finished" — yours truly

Blog (Utility & Zip): http://barnaclemikeboats.blogspot.com/
Website of Boat Photos: https://michaelsmaddox.wordpress.com

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Re: Michael's ZIP

Post by BarnacleMike » Tue Aug 21, 2018 3:56 am

Here are a couple of photos of the half-lap joints with the butt blocks. The backing strengthened the joints tremendously. I started notching these into the frames on the starboard side this morning. All 3 floor battens are now installed on the port side.
Attachments
IMG_0754.jpg
IMG_0756.jpg
-Michael

"How long does it take to build a boat? Until it's finished" — yours truly

Blog (Utility & Zip): http://barnaclemikeboats.blogspot.com/
Website of Boat Photos: https://michaelsmaddox.wordpress.com

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BarnacleMike
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Re: Michael's ZIP

Post by BarnacleMike » Wed Aug 29, 2018 11:23 am

Finally got all of the floor battens installed.
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IMG_08-26-2018-004.jpg
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-Michael

"How long does it take to build a boat? Until it's finished" — yours truly

Blog (Utility & Zip): http://barnaclemikeboats.blogspot.com/
Website of Boat Photos: https://michaelsmaddox.wordpress.com

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hoodman
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Re: Michael's ZIP

Post by hoodman » Wed Aug 29, 2018 12:11 pm

Your plan with the transom is going to ensure the transom/batten joints are really solid.
Matt

Building a Geronimo......!
viewtopic.php?f=2&t=25139

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Re: Michael's ZIP

Post by BarnacleMike » Thu Aug 30, 2018 4:19 am

Thanks, Matt! This way also just seemed easier to me than trying to end-fit the battens into closed notches the "standard" way.

I'm giving some serious consideration to using plywood web bracing on the floor battens, as described in the Glen-L book. I like the idea of the added reinforcement to the half-lap joints on 2 of the battens (even if it is overkill).

I've been trying to find some examples in the forum, of someone having done this before, but so far I haven't found anything. I'd like to get some input / perspective from someone who has built floor supports this way.
Attachments
IMG_08-30-2018-003.jpg
IMG_08-30-2018-001.jpg
IMG_08-30-2018-002.jpg
-Michael

"How long does it take to build a boat? Until it's finished" — yours truly

Blog (Utility & Zip): http://barnaclemikeboats.blogspot.com/
Website of Boat Photos: https://michaelsmaddox.wordpress.com

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