Question about ZIP keel

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Bill W
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Question about ZIP keel

Post by Bill W » Mon Jan 30, 2017 4:55 pm

Having trouble finding full 1 inch thick lumber for the keel. I have access to 3/4 " Sapele that I've been using for frames. Does any one have any suggestions ?

Thanks.

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Bill Edmundson
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Re: Question about ZIP keel

Post by Bill Edmundson » Mon Jan 30, 2017 5:08 pm

I would just laminate 2 pieces of 3/4. You'll be fairing off a good bit of material anyway. Some one else with Zip plans may say the one inch is nominal which means it's actually 3/4". It won't hurt to be thicker.

Bill
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hoodman
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Re: Question about ZIP keel

Post by hoodman » Mon Jan 30, 2017 5:23 pm

Do the zip instructions say to laminate the inside of the keel with plywood? If so, I would think 3/4 is fine. Or does it say 1" net?
Matt

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Roberta
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Re: Question about ZIP keel

Post by Roberta » Mon Jan 30, 2017 5:49 pm

If I remember correctly, the thickness was nominal, so a full 3/4" will be fine.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

Bill W
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Re: Question about ZIP keel

Post by Bill W » Mon Jan 30, 2017 7:39 pm

The slots for the keel on the frame plans measures close to 1 inch. The text says keel is 1x4 inch.

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Andy Garrett
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Re: Question about ZIP keel

Post by Andy Garrett » Wed Feb 01, 2017 4:22 pm

Stock measurements on the Zip are nominal, so 3/4 is fine. Laminating the top (inward) side with 1/4 ply might be considered best practice.
I did not do this.
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Perhaps the slowest Zip build in Glen-L history...

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Bill Edmundson
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Re: Question about ZIP keel

Post by Bill Edmundson » Wed Feb 01, 2017 4:48 pm

Bill W

Do not measure or scale from the plan sheets. These were all hand drawn. If the lines are blue (bluelines) the process stretches the paper. On hand drawn plans, it is not uncommon to draw not to scale for clarity. Trust only dimensions, and make sure they make sense.

Bill
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Moeregaard
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Re: Question about ZIP keel

Post by Moeregaard » Wed Feb 01, 2017 6:15 pm

As others have said, 3/4" will be fine. We added 1" X 1" stiffeners to our keel and battens during our latest Zip build, because the first boat in 1956 experienced some bottom flexing between the transom and Frame 2. These were installed before planking and really helped keep the keel flat and straight during construction. There are photos of what we did in the Customer Photos page under my name. Hope this helps.

-Mark Shipley
A boat is just a wooden box with no right angles.

Bill W
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Re: Question about ZIP keel

Post by Bill W » Wed Feb 01, 2017 8:10 pm

Looks like stiffeners on top of the keel between the frames. Is this true ? How did you attach them ?

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Re: Question about ZIP keel

Post by hoodman » Thu Feb 02, 2017 4:37 am

It would be easier to do a plywood lamination on the inside of the keel before you install it. Then just cut the notches slightly deeper to accept it. It has the added advantage of helping to keep the keel from splitting.
Matt

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Andy Garrett
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Re: Question about ZIP keel

Post by Andy Garrett » Thu Feb 02, 2017 10:04 am

I followed Mark's build pictures very closely and drew a great deal of inspiration from them.
I too used vertical stiffeners on my battens and two on my keel. This made affixing seats and motorwell supports very easy.

I chose two for the keel because it was easy to lay the stiffeners to either side of the stem and transom knee.

I have no flex, and the hull never even creaked while I was stepping on the members as I put the interior together.

Mark's advice is solid indeed!
Andy Garrett

Perhaps the slowest Zip build in Glen-L history...

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Re: Question about ZIP keel

Post by gdcarpenter » Thu Feb 02, 2017 1:18 pm

On my ZIP I added approximately 5/8" thick by about 1 1/4" tall stiffeners onto my battens, I used 3 battens per side.
Then again I ran my sole or floor boards side to side and that kept the floor about 3 1/2" below the top of the bottom frames so zi could sit lower in the boat.
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Re: Question about ZIP keel

Post by Moeregaard » Fri Feb 03, 2017 6:12 am

Bill W wrote:Looks like stiffeners on top of the keel between the frames. Is this true ? How did you attach them ?
Bill, I epoxied the stiffeners to the battens while the boat was still being framed, clamping everything in place with a straightedge along the keel batten. The stiffeners do not pass through the frames. This must have worked, because the bottom is really, really flat from Frame 2 to the transom. I like to avoid using screws where I'd be likely to hit one during the fairing process. Our Zip actually has very few screws in it, and after almost nine year of use we've had no problems.

-Mark Shipley
A boat is just a wooden box with no right angles.

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BarnacleMike
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Re: Question about ZIP keel

Post by BarnacleMike » Fri Feb 03, 2017 9:31 am

Bill,

As others have stated, 3/4" may be fine. I can't really speak to that from experience, so I won't add an opinion. I can say that I will NOT be using 3/4" on mine.

That being said, I would ask: Have you already cut 1" deep notches for the keel in the frames?

If so, I would plan to add the additional thickness by laminating a second layer. One option would be to laminate a layer of 1/4 plywood to the topside surface of the keel (definitely NOT the bottom). This is the way the Utility keel is designed.

As Bill Edmundson mentioned, you can also simply add a second layer of 3/4 Sapele. If you choose to do that, here is another thought:

Since the forward end of the Zip's keel requires a pretty substantial bend into its notch in the stem, you could install the initial 3/4 keel first. It should bend easier than thicker material. Then, once you have that part installed, you could add a second layer of Sapele, bending it to match the first.

Just a thought.
-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

Bill W
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Re: Question about ZIP keel

Post by Bill W » Sun Feb 05, 2017 8:04 pm

Great feedback, thanks to all. I've trial clamped the keel in place and it is dead flat from transom to frame 5 1/2. I think I'm going with the stiffeners from transom up to frame 5 1/2 , between the frames.

Thanks again. I'll probably be back soon.

Bill W.

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