panga 22

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TomW1
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Re: panga 22

Post by TomW1 »

jljones wrote: Thu Apr 08, 2021 12:53 pm
panga 22, it does not show the DWL and I would like to know how much weight before water would come in the suppers? Plans say 8 inch draft, also 7 1/4 from bottom to cockpit sole
Okay here are the specs: listed in the study plans.
Hull weight 1100lbs
Displacement lbs. 2000lbs
PPI at DWL 420
Draft at Displacement 8" also DWL

What does all this mean. The hull weight includes some basic rigging and fuel tank. So for the displacement weight you need to add the motor weight and gas, people, safety gear, fishing gear, coolers and ice, and weight of drinks you take out with you. Basically what the boat would weight at the dock. If it is more than 2000 then you have 420lbs before you add an inch of draft. The Draft is the same as DWL. On Jacques larger boats like the Panga22 the scuppers are at least 2" above the DWL if now more. You can call the office and ask.

Jacques recommends a 40-75HP motor, a 75HP Yamaha weighs 353lbs. So that is where you start in calculating your waits of your finished boat. Once you are done with the boat I have calculators that can calculate top speed and prop size needed.

I love the bigger Panga's

Regards, Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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VT_Jeff
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Re: panga 22

Post by VT_Jeff »

cape_fisherman wrote: Thu Apr 08, 2021 9:02 pm Aramid should be burried deep in the laminate of wood boats. It is incredibly hydroscopic, and if any of it gets abraded or otherwise exposed to water, it will soak it up like a sponge.
That has definitely not been my experience. My wife and I have paddled boats with kevlar bottoms on whitewater for years, smashed them on rocks, repaired them with minimal skills and never noticed any effects of water absorption, possibly be cause we never looked.

I'm probably the least qualified to comment on this topic but I did find this interesting:
Capture.PNG
from https://apps.dtic.mil/dtic/tr/fulltext/u2/a074547.pdf
There are only two seasons in Vermont: boating season, and boat-building season.

Completed Paul Butler 14' Clark Fork Drifter
Completed Jacques Mertens FS14LS + 10%, Build Thread
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jljones
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Re: panga 22

Post by jljones »

I new Kevlar protects well from abrasions , but thought it was strong to, so I did a test ,
2inch by 1/8 inch by 30 stip of plywood, covered one on both sides with 5 oz kevlar and the second one with 2 layers of 6 oz glass( did not have 12 oz)

the photo shows results , the glass is stiffer but maybe the kevlar is as strong? will try to break after the epoxy has more time to cure.
kevlar test.jpg

fallguy1000
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Re: panga 22

Post by fallguy1000 »

Kevlar likes to float in the laminate. This is defeatable a few ways. Typically by burying it between layers of glass.

Or in the case of those fancy canoes, someone is using vacuum.

It is rather difficult to repair if abraded and can require grinding out the entire section which can be difficult because it likes to make a rats nest in grinding. I have not done it and only seen pictures. What is odd is I have had a hard time finding pictures online, but their used to be plenty. Kevlar conspiracy or bad googles?

What does floating in the laminate mean? It means the fabric likes to rise up and not allow epoxy impregnation. One way to defeat it is a resin rich layup. Of course, a resin rich layup of fiberglass is generally not a great thing. When I built it into the beaching keel it was one of 8 layers of glass in mould and it was a very wet layup. Probably around a 1/4" thick stuff and the kevlar is toward the outside. I only added the kevlar in order to protect the hull in a bad reefing. I didn't mind a resin rich layup because it is 8 layers thick. Testing resin rich layups was interesting. They damaged easier from impact testing. We lifted the hulls on the beaching keels and noted no issues with 1600 pounds of pressure on 16 sqin of surface.

The test below is really only to be done after about three days room temperature curing. Otherwise it is very inconclusive. The fabric certainly has data that would support how to use it vs glass.

But the main concern is the same. How would you keep it from floating and ensure the aramid/kevlar matrix gets fully wetted. Keep in mind another problem with fabrics that float is there becomes more epoxy on the bottom and it can start to puddle and you don't realize it. In my small mould, it didn't matter, I installed a 6-8" wide piece of aramid and it floated, but I added another piece of glass above and forced it down with consolidation rollers and so had good wetout across the substrate (more glass), the aramid, and the glass on top which was 1708. If you don't use some strategy, the aramid might float, for example, on a final layer.

So, if you were to sub aramid, you'd probably need it on the bottom layer, for example. Once you wetout the substrate, roll the aramid off tubes, get it to lay down nice and then perhaps more epoxy overtop of it and then roll off fiberglass, run the consolidation roller again and wetout the top glass well from underneath. This would force any aramid resins up. Then finish with wetting out the glass. A lot of words, but aramid under is the only way I'd attempt it. Another reason would be if you sand through to the kevlar in fairing, it could become a nightmare to fix. If you sand to glass, you know to stop.

After all of this, one must ask why. For abrasion resistance.

But we've buried the aramid to use it.

Here is what I recommend. Get a small piece of aramid, say 8" wide. Laminate it to a board. After you have allowed a 3 days cure. Hit it with a sander. See if you like what happens. Then try to repair it.

A much cooler fabric to use on a panga would be carbon! It would lighten the boat.
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jljones
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Re: panga 22

Post by jljones »

ok, yes the fraying when sanded into it is a problem, but I covered the buttom of my cedar strip dinghy and it did not float up at all, slower wetting out process but I made sure not to get to much resin on it,
but it is not as stiff as the glass, I will not be using the Kevlar, there is a Kevlar/Carbon weave . BBC has it at 40 dollars a yard, but the price goes up even more, I was just trying to make it lighter.

Thanks for the information on DWL question, I love the plans and feel confident that it will not be a problem, I will get it light and simple.

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Re: panga 22

Post by fallguy1000 »

jljones wrote: Sun Apr 11, 2021 10:19 am ok, yes the fraying when sanded into it is a problem, but I covered the buttom of my cedar strip dinghy and it did not float up at all, slower wetting out process but I made sure not to get to much resin on it,
but it is not as stiff as the glass, I will not be using the Kevlar, there is a Kevlar/Carbon weave . BBC has it at 40 dollars a yard, but the price goes up even more, I was just trying to make it lighter.

Thanks for the information on DWL question, I love the plans and feel confident that it will not be a problem, I will get it light and simple.
We would really love some build pictures or a blog. Even more so if you decide to try carbon, but in all cases, the panga builds are fun. And you might get good advice.
My boat build is here -------->

viewtopic.php?f=12&t=62495

jljones
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Re: panga 22

Post by jljones »

ok, will do, may be waiting to fall to start but I can not wait to start, will be back on here

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Re: panga 22

Post by jacquesmm »

Good advice above.
Do not replace any glass with Kevlar, Kevlar does not have the stiffness we need. If you feel comfortable working with Kevlar, you can add some for resistance to abrasion.

BTW, there are two types of aramid fiber named Kevlar, one is used for resistance to abrasion, one for puncture. I do not specify it in any of my designs. For abrasion resistance, I prefer a coating of graphite in epoxy.
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VT_Jeff
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Re: panga 22

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jljones wrote: Sat Apr 10, 2021 2:04 pm I new Kevlar protects well from abrasions , but thought it was strong to, so I did a test ,
2inch by 1/8 inch by 30 stip of plywood, covered one on both sides with 5 oz kevlar and the second one with 2 layers of 6 oz glass( did not have 12 oz)

the photo shows results , the glass is stiffer but maybe the kevlar is as strong? will try to break after the epoxy has more time to cure.kevlar test.jpg
I like the test!

I know you may have already decided to shelve the Kevlar idea but this is still an interesting topic.

From what I can tell from the photo, that is not a biaxal glass, so for a straight-up stiffness comparison between the specced glass and Kevlar, it's apples/oranges, though it appears the glass won anyway. Full disclosure, I know exactly enough about glass to be nearly complete with my second boat.
There are only two seasons in Vermont: boating season, and boat-building season.

Completed Paul Butler 14' Clark Fork Drifter
Completed Jacques Mertens FS14LS + 10%, Build Thread
Started Iain Oughtred Tammie Norrie

TomW1
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Re: panga 22

Post by TomW1 »

jjjones both jacquesmm and VT_Jeff point out the flaws in your testing. You need to use biaxial glass first. Second Kevlar alone does not provide the strength needed for these boats. So adding a layer will increase your costs drastically, even if you add it only to the bottom. As Jacques said adding graphite to epoxy is a good abrasive resistant coating. I have it on my OD18. You can see it on many of the other boats builds here.

Good luck on your build and look forward to following it when you start, lots of pictures please. :D

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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