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Svensk
09-30-2008, 10:29 AM
I'm currently building this boat. It has become #1 on "My Bucket List", but hope it'll take some time before I kick it. The Bucket, that is. I'm having a BALL building it. All White & Red Oak. Instead of steam bending the ribs, I soaked them in Ammonia and water, for 2 weeks. That made them bend like wet noodles. With one drawback; it discolored the White Oak to look almost like treated pine lumber (greenish/brown). How come? But they surely hold the shape.
I'm making some design changes, like a bow & aft seat plus decking. Now, I have a question. The boat will be skinned in heat shrunk Dacron. Can I for the sake of strength add an additional layer of 4oz XYNOLE Polyester Flexible Fabric on top of the Dacron?
Please look and critique my progress.
http://www.PictureTrail.com/petelitz
Sincerely...........Pete

Darren McClelland
09-30-2008, 10:50 AM
Pete

I built the snowshoe canoe with students about 11 years ago and we built three had a great time the only problem we had was the kevlar string, I had a hard time pulling it tight and keeping it tight other then tahat things went well, we found the dacron once varnished was quite strong.
nice looking project .

capt Sawdust

Greg Nolan
09-30-2008, 11:02 AM
Very nice looking work. I have the plans for the Airolite Snowshoe 14, and am waiting for some spare time (yeah, right) to use, so I am interested in the answer to your question, but have a couple myself.

First, why are you considering Xynol instead of just a second layer of Dacron, as described in the FAQ section of the Monfort website?

Second, can you tell us more about bending with ammonia? Did you use anhydrous ammonia, or something else? What procedure did you follow?

I look forward to the pictures of the completed seats and deck.

MikeWinVA
09-30-2008, 11:12 AM
That is a pretty boat and a nice job. I have a set of the 14' Classic plans and haven't started yet.

I have read of other Geodesic builders using double layers of fabric. Some have used a flexible bedding (rubberized) to glue the layers together.

Why use the ammonia with the water?

Thorne
09-30-2008, 11:12 AM
Very nice!

Have you tried asking the designer? I'd be careful about over-building.

Ditto the above question about double Dacron, or why not a thicker single layer of material? That should be MUCH easier than trying to stretch two dis-similar materials over the same hull...

Ian McColgin
09-30-2008, 11:18 AM
The Airolites I've seen and tried would not benefit from another layer. Firstly, it won't set down tight like the shrunk dacron. Secondly it adds significant weight. Thirdly, it does not improve impact resistance, which is actually stunningly high as the whole structure can deflect and due to the vessel's light weight is always modest. Fourthly, it will not improve tear resistance like if you go out of your way to bash the boat against a barnicle or mussel encrusted piling. Turns out tears are readily temp-fixed with gaffers' tape and later fixable with a little dope and cloth.

Make her as designed and enjoy.

G'luck

Canoez
09-30-2008, 11:18 AM
Sadly, you cannot ask the designer. Platt Monfort passed away a number of years ago.

Cuyahoga Chuck
09-30-2008, 11:27 AM
Ammonia bending of wood is an industrial process using ammonia gas, which is under pressure, in a sealed system. It works wonderfully but is not for the do-it-yourselfer.
Some amateurs have reduced this to soaking wood in household ammonia. It's not the same thing. If soaking wood in household ammonia was a prooven way to do general wood bending I suspect it would have put a big dent in the use of steam boxes.

Ian McColgin
09-30-2008, 11:29 AM
Seconding Chuck - I've bent oak quite easily that was just soaked off the stern for a couple of weeks. I doubt the ammonia added any significant flex.

john l
09-30-2008, 11:37 AM
gustav stickley of craftsman furniture fame and the arts and crafts movement
at the turn of the 20th century fumed his oak furniture in amonia rooms. the idea was to have the tanins in the oak help to change the wood a deeper and richer color. then they used stains where necessary to create an even
color before applying a shellac based finish. some of his furniture was stunningly beautiful and some it quite heavy and caveman like. in your case the contrast between the heaviness of the fumed wood and the lightness of construction might be interesting - i'll have to look at your fotos.
in any event, i would build as speced. they are amazingly rugged little boats.

john l
09-30-2008, 11:41 AM
just scanned the fotos. looks great. how do you plan on finishing the wood
prior to skinning?
i've always wanted to build one of these myself.

gert
09-30-2008, 12:11 PM
I love these boats, so I thought I would offer this up, from the net:
http://www.gaboats.com/graphics/classic12_suitcase_400.jpg
for those not familiar with the construction concept.

Hope ya don't mind...

Svensk
09-30-2008, 03:12 PM
Fellows. Thanx one and all for your comments. To answer some of the questions:
1. Using a mixture of Ammonia and water to bend wood, is an old Viking method. They actually buried their wood in the marsh land and latrin, so it wood bend easier. What the ammonia does to the tanin, I don't know. All I know, it worked very well.
2. I give praise to Mr. Platt Monfort. His design is superb. But as a designer, I don't think he would have minded my changes at all.
3. I'm now convinced. One or maybe two layers of Dacron would be sufficient. I think you guys know what you're talking about. Plus, I'm not going to use the Kevlar roving (too many problems).
4. I will finish the woodwork and Dacron with MINWAX's HELMSMAN Spar Urethane (Clear Semi-Gloss?).
5. Another reason for doing some changes in the design is this. This is, as you can see from the heart on the transom, the original LOVE BOAT. She will be named after the love of my life, PATRICIA, and there will be a seat for her too. (Fellows. I ain't stupid!)

In closing. I truly appreciate all of your comments and suggestions. Some of them I will favor and some will fall at wayside. As time goes, I will add more pictures, to show you my progress. Sincerely...........Pete

Tom Robb
09-30-2008, 03:23 PM
"You can lead a horse to water...."

Svensk
09-30-2008, 04:02 PM
Tom.
"We're about the same age, and you know you cain't make'm drenk!"

MikeWinVA
09-30-2008, 04:37 PM
What is the ratio of ammonia and water and the type used?

MiddleAgesMan
09-30-2008, 05:08 PM
Very nice work, Svensk. She's already got a great look to her so she will be stunning once you get all those holes filled. ;)

Did Montford's plans provide details about each tiny bit of wood or did you have to fill in the blanks? If the latter, you certainly have a talent for turning a bunch of tiny bits into a great looking boat.

Please do keep us updated on your progress.

Cuyahoga Chuck
09-30-2008, 05:17 PM
"Plus, I'm not going to use the Kevlar roving (too many problems)."


Platt Montfort developed that boat construction method from a similar method used to make ultralight aircraft. If the flyboys say "Kevlar", they had a reason and you would be wise to use "Kevlar". There is no fiber that's even close to Kevlar in terms of tensile strength. Kevlar fiber is supposed to be about 10 times stronger in tensile strength than an equal weight of steel.
Since you are building in a medium that accentuates minimum weight you don't have a a large margin of excess strength to play with.

Canoez
09-30-2008, 05:24 PM
"Plus, I'm not going to use the Kevlar roving (too many problems)."


Platt Montfort developed that boat construction method from a similar method used to make ultralight aircraft. If the flyboys say "Kevlar", they had a reason and you would be wise to use "Kevlar". There is no fiber that's even close to Kevlar in terms of tensile strength. Kevlar fiber is supposed to be about 10 times stronger in tensile strength than an equal weight of steel.
Since you are building in a medium that accentuates minimum weight you don't have a a large margin of excess strength to play with.
You could probably use Specra as a Kevlar replacement - they have very similar tensile strength. I think their low stretch properties are what makes it difficult to tension the thread.

MikeWinVA
09-30-2008, 05:55 PM
Spectra is ultra high molecular weight polyethylene (UHMWPE), also known as high-modulus polyethylene (HMPE) or high-performance polyethylene (HPPE). It has the highest impact strength of any thermoplastic presently made. It is highly resistant to corrosive chemicals, with exception of oxidizing acids. It has extremely low moisture absorption, has a very low coefficient of friction, is self-lubricating, and is highly resistant to abrasion (15 times more resistant to abrasion than carbon steel). Its coefficient of friction is significantly lower than that of nylon and acetyl, and is comparable to that of Teflon, but has better abrasion resistance than Teflon.

It is very resistant to water, moisture, most chemicals, UV radiation, and micro-organisms. It is 1.4 times stronger than Kevlar for the same weight. It is 10 to 100 times stronger than steel for a given weight. Under extreme load it will creep (cold flow) much more so than Kevlar and will not rupture abruptly like Kevlar. Its modulus of plasticity is much greater than Kevlar but its modulus of elasticity is similar.

Since it is available as woven line it is not as difficult to work with as Kevlar yarn. It does not need to be coated with varnish to protect it from UV degradation like Kevlar. I haven't seen it tested, but I think that coating Kevlar with varnish might significantly weaken it by introducing stress risers and localizing loads.

From an engineering standpoint, spectra is superior to Kevlar in this application and is easier to use.

Todd Bradshaw
09-30-2008, 06:16 PM
"From an engineering standpoint, spectra is superior to Kevlar in this application and is easier to use."

Except for the creep factor, which is, unfortunately, the one which is most important here.

Svensk
09-30-2008, 06:23 PM
Again, Thanks fellas.
MikeWinVa:
Are you going to construct yours in White Oak? As far as the ratio ammonia-water. Your ribs on the 14'r are the same as mine, 64" long. I purchased a 4" dia. X 7' PVC pipe, glued a cap on one end, placed my ribs inside and poured 2 gallons of ammonia in first. Then topped it off with water. Naturally the ribs will want to float, so you push them down with another cap (do NOT glue that cap) and let it stand around for some time. Then pour out the "mess" and attach them to the stringers, using electricians cable ties. Use gloves, the ammonia will eat your skin.
Middleagesman:
There are no small pieces. The rectangular shapes are made by the stringers (6) over the ribs (19). The smallest pieces so far are the Gunwale Blocks, holding the ribs, between the inner and outer gunwales.
Cuyahoga Chuck:
You're absolutely right about the tensile strength of Kevlar roving. However when the "flyboys" first draped their planes in cloth, there were no Kevlar. I have also seen a Dacron skinned boat, built at the Dartmouth University, without any Kevlar roving. And it's holding up just fine. One more thing, I'm adding braces to the floorboarding and I don't want to go through with the "hassle" and headache of stretching Kevlar. Sorry Mr. Monfort.

After all, I MIGHT be stupid.
Pete

Fitz
09-30-2008, 06:48 PM
How thick are the ribs?

Looks like they would bend without Windex anyway.;)

Cuyahoga Chuck
09-30-2008, 06:55 PM
Again, Thanks fellas.
MikeWinVa:
Are you going to construct yours in White Oak? As far as the ratio ammonia-water. Your ribs on the 14'r are the same as mine, 64" long. I purchased a 4" dia. X 7' PVC pipe, glued a cap on one end, placed my ribs inside and poured 2 gallons of ammonia in first. Then topped it off with water. Naturally the ribs will want to float, so you push them down with another cap (do NOT glue that cap) and let it stand around for some time. Then pour out the "mess" and attach them to the stringers, using electricians cable ties. Use gloves, the ammonia will eat your skin.
Middleagesman:
There are no small pieces. The rectangular shapes are made by the stringers (6) over the ribs (19). The smallest pieces so far are the Gunwale Blocks, holding the ribs, between the inner and outer gunwales.
Cuyahoga Chuck:
You're absolutely right about the tensile strength of Kevlar roving. However when the "flyboys" first draped their planes in cloth, there were no Kevlar. I have also seen a Dacron skinned boat, built at the Dartmouth University, without any Kevlar roving. And it's holding up just fine. One more thing, I'm adding braces to the floorboarding and I don't want to go through with the "hassle" and headache of stretching Kevlar. Sorry Mr. Monfort.

After all, I MIGHT be stupid.
Pete

If you were playing with carboy of chemical grade anhydous ammonia solution you wouldn't be here to talk about it unless you had an alternative fresh air supply. You were most likely using household ammonia which is about a couple of percent ammonia, if that.
Everyone is entitled to build whatever way they prefer. The problem is we never hear back from those whose schemes don't pan out. As the old saying goes ,"failure is an orphan".
Good luck.

Canoez
09-30-2008, 07:11 PM
"From an engineering standpoint, spectra is superior to Kevlar in this application and is easier to use."

Except for the creep factor, which is, unfortunately, the one which is most important here.

How much creep are we talking about here? - Would it be significant in the application? I know that it's supposed to be continuous...

Todd Bradshaw
09-30-2008, 07:23 PM
The function of the Kevlar diagonals on these boats is primarily to support and rigid-ify (is that like strategery?:)) the lightweight frame, not to support the skin. The skin, as it is, and within the limited resistance to stretch and limited tear strength characteristics of Dacron, will take care of itself and that manner of reinforcing it wouldn't do much to change its properties. The frame, on the other hand is somewhat under-built for a boat and the diagonals can make a big difference there. Kevlar, being more resistant to stretching when left loaded (creep) is a better choice for maintaining this rigidity.

Svensk
09-30-2008, 08:16 PM
If you were playing with carboy of chemical grade anhydous ammonia solution you wouldn't be here to talk about it unless you had an alternative fresh air supply. You were most likely using household ammonia which is about a couple of percent ammonia, if that.
Everyone is entitled to build whatever way they prefer. The problem is we never hear back from those whose schemes don't pan out. As the old saying goes ,"failure is an orphan".
Good luck.
You're correct Chuck. Had I used Anhydrous Ammonia, I would not be around to talk about it. In the first place as a "privateer", you can't get a hold of it. My ribs are 9/32" x 5/8" x 64". I even built a very fine steam box and was ready to fire it up as I took the first rib out. The ribs felt very "limp", so I tried to bend it around the 4" PVC pipe. It worked very well. So I did not fire up the steam box. Out of the 19 ribs I installed, I only broke 2, and that was because of the direction of the wood grain (had extras soaking). I had them all attached, by myself, in less than an hour. Naturally, #1 and #2 ribs from the bow are in 2 pieces, but #3 has a very tight bend. Take a look at my pictures.
Chuck, I appreciate your comments. Thanx.......Pete

MikeWinVA
09-30-2008, 08:28 PM
Canoez, creep starts to occur near the failure load not the working load.

I don't think you could get an 1/8" line of spectra to failure load until it was loaded to the point of breaking the hull stringers on this craft. Creep is not an issue until it is loaded near to its failure load. Spectra lines are less elastic than polyester lines and only become plastic near their point of failure. They do not continuously cold flow like nylon does under load. Spectra lines are being used to replace steel cables in some cranes and hoists.


Part of use the kevlar or spectra is to spread localized loads to the entire hull. It will stop the hull from oil canning and twisting. If you plan to sail at all, a great deal of torsional load will be transmitted from the mast step, partners, centerboard, and displaced weight. 50 pounds of pressure at the peak of a 12' mast will put a possible torsional load of about 600 ft lbs at the base if the distance between the partner and the step is a foot.

Todd Bradshaw
09-30-2008, 10:35 PM
Creep is a factor at lighter loads as well, though it isn't a massive amount. Still, if you have an 8' long diagonal reinforcing piece and it slowly stretches a percentage point or two, you would be looking at upwards of an inch of stretch, which probably isn't too good for keeping things rigid. This is why despite all its great features and strength, it rapidly fell out of favor for high-tech racing sails. You can read more than you probably ever want to know about spectra creep here (pages 227-231 or so)
https://www.ing.unimo.it/campusone/MaterialeDidattico/Matdidattico2284/HPC_10_Organic_fibers.pdf

Svensk
09-30-2008, 10:55 PM
OK, Mike & Todd.
"I'm creeping, loading and tensing. And don't know if coming or going".
One thing I know. I'm going to bed.
Pete

Svensk
10-01-2008, 02:00 AM
How thick are the ribs?

Looks like they would bend without Windex anyway.;)
Fitz. I see by your personal profile. Occupationally we are the same:
"A down to the earth person with rocks in the head"But I'm retired now.
No punt intended............Pete :D

Fitz
10-01-2008, 06:24 AM
Very cool Svensk - were (are) you an petroleum/exploration geologist?

Keep us posted on your project. These geodesic boats are interesting.

Cheers.

Fitz

Andrew
10-01-2008, 06:55 AM
http://pic60.picturetrail.com/VOL1748/11638398/20655261/336639780.jpg
Too state the obvious... beautiful.

Sorry if I missed it, but what are you using if not Kevlar?

Canoez
10-01-2008, 07:31 AM
Canoez, creep starts to occur near the failure load not the working load.

I don't think you could get an 1/8" line of spectra to failure load until it was loaded to the point of breaking the hull stringers on this craft. Creep is not an issue until it is loaded near to its failure load. Spectra lines are less elastic than polyester lines and only become plastic near their point of failure. They do not continuously cold flow like nylon does under load. Spectra lines are being used to replace steel cables in some cranes and hoists.


Part of use the kevlar or spectra is to spread localized loads to the entire hull. It will stop the hull from oil canning and twisting. If you plan to sail at all, a great deal of torsional load will be transmitted from the mast step, partners, centerboard, and displaced weight. 50 pounds of pressure at the peak of a 12' mast will put a possible torsional load of about 600 ft lbs at the base if the distance between the partner and the step is a foot.

Yep. I'm an engineer - I get what you're saying - particularly about the distributed load - no one fiber should be near it's tensile strength and hence, shouldn't see much elongation. Still, the Honeywell specs call for 6-8% elongation. IIRC, the fibers used in these boats is pretty small stuff - on the order of about .060 or so - If I'm wrong, somebody let me know. The other issue is that the Spectra has a fairly low temperature limit and starts to have strength issues around 200F

In terms of creep, we have seen creep happen at room temperature in parts with a small axial load (Cast Polyurethane housings) It's insidious and doesn't need extremes of temperature or force to occur, but simply takes a longer time.


Creep is a factor at lighter loads as well, though it isn't a massive amount. Still, if you have an 8' long diagonal reinforcing piece and it slowly stretches a percentage point or two, you would be looking at upwards of an inch of stretch, which probably isn't too good for keeping things rigid. This is why despite all its great features and strength, it rapidly fell out of favor for high-tech racing sails. You can read more than you probably ever want to know about spectra creep here (pages 227-231 or so)
https://www.ing.unimo.it/campusone/MaterialeDidattico/Matdidattico2284/HPC_10_Organic_fibers.pdf

Thanks for the data - good stuff.

I've got a real interest in this stuff from a professional point of view. We make flexible endoscopes and some are approaching lengths of 6 meters. We presently use pre-stretched stainless steel cables about .025" in diameter and are looking at Kevlar for a replacement, but the internal friction (even with waxed fiber...)tends to screw it up over use. Still haven't found the magic solution.

Anyway, I'd like to build a SOF canoe one of these days and was wondering at the use of some of these other fibers - like Dyneema, Vectran and similar products.

ChrisBen
10-01-2008, 08:04 AM
Nice job Svensk. I've built two of them, the Nimrod 12 and the Classic 14. Fun to build and amazingly light. I wouldn't leave out the Kevlar roving, I think there would be to much twist in the frame without it. I've been using the Nimrod for 16 years now and just the one layer of heat shrink dacron with varnish has been sufficient. I do have a few holes in the skin but as Ian pointed out above, Duct tape is an instant fix till you get home and make a patch from the left over dacron and epoxy.
http://i143.photobucket.com/albums/r133/loki59/loki.jpg
http://i143.photobucket.com/albums/r133/loki59/canoe5-1.jpg

Svensk
10-01-2008, 09:28 AM
Very cool Svensk - were (are) you an petroleum/exploration geologist?

Keep us posted on your project. These geodesic boats are interesting.

Cheers.

Fitz
Hi Fitz.
Answer: Yes, with former ARCO Oil & Gas Co. Exploration / Research and Development. Clay Mineralogy. Retired 1993, before reorganization and overtake by BP. I don't miss it and would rather build boats.
Back to ya.............Pete

MikeWinVA
10-01-2008, 02:29 PM
ChrisBen,

How does the Classic sail?

ChrisBen
10-02-2008, 08:29 AM
ChrisBen,

How does the Classic sail?Hey Mike, It sails fine. I used a windsurfing rig I had. It was a 6.5 sq. meter sail, approx. 70 sq. ft. The boat was a bit tender in heavier winds with just myself aboard but with another person it had enough ballast to settle down. The classic is really a pulling boat so it rows better than it sails. If you're planning on building one of the geodesic boats for sailing I'd recommend the "Blivit 13". Blivit 13 - Geodesic AiroLITE Boats (http://www.gaboats.com/boats/blivit13.html)

Dave Hadfield
10-02-2008, 08:57 AM
I built one and still have it. I used it as a tender on a small sailboat. I loved reaching over the rail and pulling it aboard with one hand.

The light rib-and-stringer frame has no ridgidity at all without the kevlar ribbon. None. But once the ribbon is applied, the structure is amazingly stiff, with almost no weight gain. I wouldn't use cord because it would not lie flat, which is key.

The hull is quite strong because, as was said, the whole side will "give" a little with an impact. It's even reasonably resistant to puncture by rocks or logs on the bottom. Two layers would be redundant, in my opinion.

What I found was pinholes. Large gains of sand tend to work their way in between the ribs and the dacron over time. The dacron gives way and a little bump results. No problem, until you skim something hard, and then the top of the bump erodes and you get a tiny pinhole leak.

If I build another of these, I'd put a layer of thin foam weatherstripping on the ribs before the dacron. It would eliminate the hard-point, and the pinholes.

I love throwing the canoe in the air up on one end, and catching and balancing it like a garden rake!

Dave

Svensk
10-02-2008, 08:14 PM
Very nice looking work. I have the plans for the Airolite Snowshoe 14, and am waiting for some spare time (yeah, right) to use, so I am interested in the answer to your question, but have a couple myself.

First, why are you considering Xynol instead of just a second layer of Dacron, as described in the FAQ section of the Monfort website?

Second, can you tell us more about bending with ammonia? Did you use anhydrous ammonia, or something else? What procedure did you follow?

I look forward to the pictures of the completed seats and deck.
OK, Greg.
I got a couple of days in on the boat. Finished the seats/decks. Next will be the skeg and then the floorboards.
I think by now, I'm totally convinced to use the Kevlar roving, after all. Why I was even thinking about a second layer of Xynol is the tear strength of the material. There are some pretty smart fellows out there and I am listening. Take another look at my progress. http://www.picturetrail.com/petelitz
Pete

Tom Robb
10-03-2008, 05:19 PM
Are the big blocks around the ribs at the gunn'ls and the short transom knees per the plans?

Svensk
10-03-2008, 11:32 PM
Are the big blocks around the ribs at the gunn'ls and the short transom knees per the plans?
Tom.
The gunwale blocks are actually per plan spec. The transom knees are not. Instead of placing a spacer between the outer and inner gunwales and then the transom knees on top of the inner gunwales. I just made it all in one piece and doweled it through the transom.
Thanks for your interest............Pete
http://www.picturetrail.com/petelitz

Svensk
10-09-2008, 04:04 PM
Just another update. Put some shine on her and fitted the skeg. Next will be the floorboard.
http://www.picturetrail.com/petelitz
Pete

Fritz Koschmann
10-10-2008, 03:19 AM
Here is my Classic 14. I added a second layer of Xynole and am glad I did. The first layer of dacron was installed as designed. I admit that I had no experience with skin boats before this but the single dacron skin seemed insubstantial to me. I wanted something more rugged. The xynole second layer certainly added weight but the boat is still very light. I made up a test panel of the same layup, shrunk dacron and xynole/epoxy and I couldn't damage it with a hammer, no cracking or delamination. Of course only time will tell. The xynole layer was a hassle to apply. Steamed white oak ribs, sitka spruce and a little bit of alaska yellow cedar.

http://eeddcc.homestead.com/geo_wb.jpg



http://eeddcc.homestead.com/GEO_sml_3.jpg

Svensk
10-10-2008, 09:34 AM
Here is my Classic 14. I added a second layer of Xynole and am glad I did. The first layer of dacron was installed as designed. I admit that I had no experience with skin boats before this but the single dacron skin seemed insubstantial to me. I wanted something more rugged. The xynole second layer certainly added weight but the boat is still very light. I made up a test panel of the same layup, shrunk dacron and xynole/epoxy and I couldn't damage it with a hammer, no cracking or delamination. Of course only time will tell. The xynole layer was a hassle to apply. Steamed white oak ribs, sitka spruce and a little bit of alaska yellow cedar.

http://eeddcc.homestead.com/geo_wb.jpg



http://eeddcc.homestead.com/GEO_sml_3.jpg
Fritz.
You've got a good looking boat there. I'm glad to hear, that I'm not the only person thinking about a second layer of Xynole. Others had me just about convinced to go with a single layer of Dacron. As a matter of fact, Ross Miller (Duckworks), the designer of the Egret kayak is using this technique. This is actually my first out in building a boat. So I can use all the knowledge of others I can get a hold of. Hopefully you'll stay in touch. What kind of "problems" did you have applying the Xynole?
Thanks for the info...........Pete

Fritz Koschmann
10-10-2008, 06:39 PM
Svensk,
Most of my problem with the xynole was operator error. I had a batch of epoxy that didn't harden when I was filling the weave of the xynole. After a lot of rubbing, scraping, cursing I got past that. The relatively fragile hull couldn't stand much forceful scraping. I am used to working on mostly fiberglass/epoxy plywood hulls where aggressive sanding is the norm. The xynole requires a lot of epoxy initially to wet it out and quite a bit to fill the weave. It does not sand well as sanding raises fuzz. In areas where the cloth was overlapped at the transom and stem I found a sureform plane or scraper was useful.

I wonder too if the kevlar is needed with the xynole layer added to the dacron. It seems to me that the much sturdier hull might not need the kevlar bracing.

Todd Bradshaw
10-10-2008, 07:11 PM
Of course you guys have heard the old joke where the boat builder's employee designs a new super-duper, incredibly durable composite panel and takes it to show his boss. He says "Hey boss, check this out" and begins pounding on the panel with a hammer, where it performs admirably. The boss raises one eyebrow, takes the hammer from the man's hand, flips it over and with a single stroke drives the claw end right through the panel.....

I have no data to back it up, but that joke is what comes to mind when somebody starts talking about adding a single layer of resin-saturated composite fabric to a Dacron skin over an ultra-light frame....just something to keep in mind.

Svensk
10-10-2008, 11:40 PM
Svensk,
Most of my problem with the xynole was operator error. I had a batch of epoxy that didn't harden when I was filling the weave of the xynole. After a lot of rubbing, scraping, cursing I got past that. The relatively fragile hull couldn't stand much forceful scraping. I am used to working on mostly fiberglass/epoxy plywood hulls where aggressive sanding is the norm. The xynole requires a lot of epoxy initially to wet it out and quite a bit to fill the weave. It does not sand well as sanding raises fuzz. In areas where the cloth was overlapped at the transom and stem I found a sureform plane or scraper was useful.

I wonder too if the kevlar is needed with the xynole layer added to the dacron. It seems to me that the much sturdier hull might not need the kevlar bracing.
Fritz.
So what you are saying is this. YOU are satisfied with the double layer Dacron/Xynole for increased strength? I have also thought about the necessities of applying the Kevlar roving, did you?There are a lot of fellas out there, that have/had built these boats and are possitively ecstatic, without the Kevlar. My boat will probably weigh twice as much as typical CLASSIC 12 and likewise twice the time. I'm out to build "a good looking, seaworthy boat", that I can take my wife out on for a picnic. I care very much for the design of the boat. I think Mr. Monfort, RIP, would encourage sound fundamental changes in the construction.
As is said in this Norseman prayer:
Wisdom is the reward you get for a lifetime of listening when you'd have preferred to talk. http://www.woodenboat.com/forum/images/icons/icon14.gif
Doug Larson

MiddleAgesMan
10-11-2008, 08:37 AM
The seats are artful, Svensk. I love the way you laid out the slats.

Are the longitudinal wood strips glued to the ribs? Is that what the plans call for?

My take on the kevlar roving-- There is nothing about the interaction between the various wood members to resist twisting or shifting when stress is applied to the hull. Leaving out the kevlar would be like building a stud wall without the diagonal bracing or without plywood sheathing to hold everything square.

Svensk
10-11-2008, 06:19 PM
The seats are artful, Svensk. I love the way you laid out the slats.

Are the longitudinal wood strips glued to the ribs? Is that what the plans call for?

My take on the kevlar roving-- There is nothing about the interaction between the various wood members to resist twisting or shifting when stress is applied to the hull. Leaving out the kevlar would be like building a stud wall without the diagonal bracing or without plywood sheathing to hold everything square.
Thanks for the kind words, regarding fore and aft seats. Yes, the longitudinal strips (stringers) are epoxied to the ribs.
Got a full day on the floorboards today. More tomorrow then the oarsman's seat.
Pete
http://www.picturetrail.com/petelitz

Svensk
10-20-2008, 06:06 PM
10-20-08. Finally got to the point of laying in some floor boards. Five down and four to go. Still having a ball.
http://www.picturetrail.com/petelitz

45LCshooter
10-20-2008, 10:56 PM
I am confused by some of the highly technical lingo here...roughly how long is "for some time"? I understand things are bigger in Texas....

"and let it stand around for some time. Then pour out the "mess" and attach them to the stringers, using electricians cable ties. Use gloves, the ammonia will eat your skin."

Svensk
10-20-2008, 11:53 PM
I am confused by some of the highly technical lingo here...roughly how long is "for some time"? I understand things are bigger in Texas....

"and let it stand around for some time. Then pour out the "mess" and attach them to the stringers, using electricians cable ties. Use gloves, the ammonia will eat your skin."

:( English being my second language, I've made a mistake and not introduced some new technical lingo. "for some time" is typically an open time period. In my case "for some time" lasted 14 days. Yours could range more or less. As far as pouring out the "mess", I was reffering to the discoloration of the water/ammonia from the White Oak ribs before attaching them to the stringers.
As far as "everything's bigger in Texas, I haven't seen all of it yet".http://www.woodenboat.com/forum/images/icons/icon10.gif
Anything else I can help you with?

Thorne
10-21-2008, 10:13 AM
Looking good! Can't wait to see her finished....

http://pic60.picturetrail.com/VOL1748/11638398/20655261/339567908.jpg

Svensk
10-21-2008, 02:55 PM
Thanks Thorne.
It's always nice to get compliments, particularly for a first time builder and for an old man like me. I sure got started at an old age. But I'm having fun with it and that's the main purpose.
Got all of the floor boards in today. But it's fixin to rain so that's it for today. Cheers and THANKS again.
http://www.picturetrail.com/petelitz

Kermit
10-23-2008, 11:28 AM
USE THE KEVLAR! Platt put it there for good reason. I've built some of these boats, and can't imagine these frames holding up without the kevlar. Those little epoxy rib-stringer joints would not likely take a lot of stress.

Put on a second layer if you want. I just use 'em sensibly without problems.

Just my $.02.

Svensk
10-23-2008, 06:59 PM
Kermit, or could I call you Mr. Schwager?
I've now got about $1.57 worth and still don't know how to spend it. We Swedes are stubborn. I have seen these geodesic designs WITHOUT Kevlar. I wish there was someone out there, that did NOT use the Kevlar roving, to come on the Forum and
"Show me the money......."

Philip Maynard
10-24-2008, 08:20 AM
You have a beautiful boat. I bought the classic 12 kit but I have not started on it - I still have to finish Tom Hill's Charlotte first. I love to modify things but in this case I would follow Platt's instructions, especially something as fundamental to the design as the kevlar. If I recall he built them at first without kevlar but added it to improve stiffness. Possibly you could get away without it if you always rowed on very still water but get that thing in waves and you will want the kevlar. He had a lot of experience with it, it is a very specialized technique. Looking at that beautiful framework you can see there is nothing there to stop racking. I also wonder if building without kevlar, the boat would be so flexible that it would deform at every pull of the oars and kind of mush along - in other words aside from handling and feeling better a stiffer boat will actually row faster.

Svensk
10-24-2008, 09:00 AM
Thanks Philip.
What you're saying is starting to make some sense. Particularly about the "racking" aspect. She will mostly be rowed on Paddle Trails, in calm waters.

Svensk
10-30-2008, 01:29 PM
:) OK, I've got something to sit on now. This is not one of Mr. Monfort's original designs, but I think it fits the boat. The aft seat for the wife will be removable with a backrest (which will be the next step). This is how it looks at the moment: http://www.picturetrail.com/petelitz :D

Svensk
04-10-2009, 12:13 AM
OK friends, it's time to thaw out and get going again. You know it can get cold down here in Texas too. My boat has been tarped since October out on our patio. As soon as the weather get settled around the 70 degree mark I'll seal the the wood and get ready to attach the Dacron. But I have a question in regards to sealing the Dacron. What should I use? :confused:

Cuyahoga Chuck
04-10-2009, 10:28 AM
Basically, Monfort's designs are Skin-on-Frame. In the world of SOF kayaks almost any common paint has been used to fill the weave of the nylon or polyester skins. A favorite is polyurethan varnish because it makes the skin a translucent yellow, rather like thin animal skin. The scuttlebutt says the oil-based version is a bit more flexible than the water-based.
But, some of the bare-bones builders ( you can build one of these things for $100) use gray porch paint. Not very glamorous but it is compounded to take abuse.

DGentry
04-10-2009, 11:24 AM
Chuck is right about coating your skin just like a SOF kayak. This is a seemingly endless discussion on the qajaqusa.org forum and you can get a whole lot of information there.

Here's just one recent thread: http://qajaqusa.org/cgi-bin/GreenlandTechniqueForum_config.pl?page=3;read=1104 85

Major options: Coelan, Corey's goop, Zar oil based exterior polyurethane varnish, oil based paint, hypalon, other varnishes.

Or you could do whatever the plans call for, assuming they say something about it . . . .

Looking forward to seeing your boat!

Dave Gentry

Svensk
04-11-2009, 12:47 PM
Thanks Chuck & Dave.
I have now surfed the web and other forums and have come to the conclusion. If I was a rich man, I would go with the COELAN. But since I'm not, I think I'll go with the FAMOWOOD Dura-Tuff. A lot of the SOF kayak builders are using it and swear by it, and that's good enough for me.
By the way Dave, this is how she looks at the moment:
http://www.picturetrail.com/petelitz

ChrisBen
04-11-2009, 01:11 PM
Nice job. I used varnish on my Nimrod, 12-14 coats. It's always stored indoors during winter then in the garage during summer when I'm using it. 16 years and hasn't needed to be refinished yet.
http://i143.photobucket.com/albums/r...9/canoe1-1.jpg (http://i143.photobucket.com/albums/r133/loki59/canoe1-1.jpg)

Tom Robb
04-11-2009, 04:10 PM
I showed the wife your last picture. We both agree (rare event - I bettter go buy a lottery ticket) that it's pretty enough to hang from the ceiling as sculpture.

islandr
05-17-2009, 04:57 AM
Sounds like there are a lot of people experienced with this "geodesic" construction.
I am seriously thinking of building a sailing canoe with sof construction but am concerned about the hull having enough stiffness to sail as well as it would in, say, plywood. Would this kevlar roving be able to supply that stiffness or close? Is Monford's construction (glued joints, kevlar and dacron) and materials a better way than lashing and nylon?
I am very interested in this construction method and the kevlar roving in particular. How is it applied? "stretched, tied and glued? does it show thru the dacron and make "bumps" in the skin and do they effect the hydrodynamics? I live on Michigan's Drummond Island and the landings are often very rocky, would the dacron skin be strong/durable enough to take the stresses of sailing and careful if rocky landings with the weight of camping gear on board or would nylon be better?
Any advise or experience would be greatly appreicated.

Cuyahoga Chuck
05-17-2009, 10:02 AM
Sounds like there are a lot of people experienced with this "geodesic" construction.
I am seriously thinking of building a sailing canoe with sof construction but am concerned about the hull having enough stiffness to sail as well as it would in, say, plywood. Would this kevlar roving be able to supply that stiffness or close? Is Monford's construction (glued joints, kevlar and dacron) and materials a better way than lashing and nylon?
I am very interested in this construction method and the kevlar roving in particular. How is it applied? "stretched, tied and glued? does it show thru the dacron and make "bumps" in the skin and do they effect the hydrodynamics? I live on Michigan's Drummond Island and the landings are often very rocky, would the dacron skin be strong/durable enough to take the stresses of sailing and careful if rocky landings with the weight of camping gear on board or would nylon be better?
Any advise or experience would be greatly appreicated.

Geodesic Aerolites are ultralight hulls and you have to accept they will not be a stiff as a hull with a more stout framework.
Robert Morris did a SOF version of a "Providnce River Boat" ( a sailing dinghy with a wineglass transom) and the basic bones of his boat are much heavier than anything Monfort came up with. And having a hull covered with 12 oz. ballistic nylon, as opposed to 3-4 oz. heatshrink dacron, means you have a lot more protection from penetration. But, even ballistic nylon can be abraded if it's drug across sharp surfaces.
Morris's SOF designs are in his book "Building Skin on Frame Boats".

boatsnh
05-19-2009, 08:36 PM
This might sound a little off the beaten path as a coating, but in 2000 I built 2 of the "Wee Lassie" geodesic canoes. Love them. At the time I had a friend who is a polymer chemist in architectural coatings suggest a water base alipatic urethane coating he thought was superior to any "varnish" I might use. I used a product made by Edison Chemical called Aquathane UA-210. Clear, tough (7000 psi) and made for tough environments .... I bought a gallon, applied about 4 coats and it is about the same now as then. Perfect coating - The coating is not 'brittle' like harder coatings and has great impact resistance. I like to show folks how I can "stab" the skin with a bic ball point pen & not puncture the coating or the dacron skin. The varnish does not yellow & the skin is a "pure" white dacron - folks think the canoes are made of paper - lots of fun. You can google the coating and read about it - it's made for exterior use & has worked wonderfully - I'd not hesitate to use again. I hang the canoes in the garage year round. I,ve not had a hole in years of use - salt & fresh water in NH and Massachusetts.
Mike

seo
05-19-2009, 08:57 PM
Does your boat have a heat-shrinkable "ceconite" fabric covering? If so, do you have information on:
a) weight per square foot of material.
b) percentage that it will shrink with heat
c) How do you join fabric at seams or joints (Like at a stem)?
d) Cost?
e) Where did you get it from?
As far as the urethane goes, can it be tinted to a color?
In general, do you have an opinion on whether this woould be a good covering for a wood/canvas canoe?
Thanks
SEO

Cuyahoga Chuck
05-20-2009, 10:28 AM
Does your boat have a heat-shrinkable "ceconite" fabric covering? If so, do you have information on:
a) weight per square foot of material.
b) percentage that it will shrink with heat
c) How do you join fabric at seams or joints (Like at a stem)?
d) Cost?
e) Where did you get it from?
As far as the urethane goes, can it be tinted to a color?
In general, do you have an opinion on whether this woould be a good covering for a wood/canvas canoe?
Thanks
SEO

The Dacron used is the same stuff used by the builders of ultralight aircraft. It's only about 3-4 oz. per square yard (sorry for the imperial measurements). The coverings of traditional wood-canvas canoes is 15 oz. cotton canvas. Some modern restorers use polyester of nylon instead but, I think, the cloth weight is about the same.
If you want more expert opinions go to the WCHA web site. Those folks have done it all.

P.I. Stazzer-Newt
05-20-2009, 10:39 AM
Cheeky question, but I'll ask anyway.

What sections are:
1 Ribs
2 Stringers

burtmail
10-12-2009, 10:00 AM
On the twisting etc.: I didn't want to use kevlar roving so I overdesigned the center seat as pictured (laminated bent cross pieces.) As the Monfort dacron makes me insecure, I am planning to contact cement a second layer of heavier dacron to the shrunk first layer. Any comments or suggestions on this?

http://www.handmadechairs.com/boat1.jpg

htom
10-12-2009, 02:23 PM
In my opinion, the seat might keep the gunwales from folding into the center, but not from racking, and it will do nothing to stabilize the hull. The weight of adhesive and second skin will be far greater than the kevlar roving, and even glued to the stringers it will not provide much stability to the hull.

I'm guessing, not any kind of engineer or architect.

seo
10-15-2009, 11:23 AM
Platt Monfort trivia:
Quite a while ago I met Platt Monfort at his shop in Maine. He had a sailboat hull for sale, It was a L.F. Herreshoff boat, either a Neriea or the 44' clipper bowed ketch whose name I can't remember right now.
The construction method was something that I think he called "ferro-lite," which was a steel armature like a ferro-cement boat, but instead of using portland cement it was plastered with polyester putty.
He was an inventive fellow, full of enthusiasm.
I think he might also have been involved in a project back in the 1970's with a guy who had a shop on Westport Island in Wiscasset, where they had set up for building Herreshoff H-28 hulls conventional plank construction, built upside down over a form.
SPECTRA
A few years ago I was running a tug, towing a pair of hopper barges for a dredge project. One barge had a towing bridle made with 1.25" steel wire, which took three guys to handle. The other barge's bridle was made of Spectra, the first time I'd ever seen the stuff. It was so light that it floats, so light that one guy could pick up and carry both legs of the bridle. It was sort of creepy that something so light could be so strong. I realize that this sheds no light on the question of creep in an engineering sense.

Svensk
10-21-2009, 11:24 PM
Friends, please go to: FORMERLY GEODESIC CLASSIC 12 thread. :D
http://www.picturetrail.com/petelitz