North Water lacing d rings

[Paddlinhal]

My buddy got these odd looking plastic d rings in his float bag kit. He wants to mount them on his vinyl gunwales, but how? To the underside? They fit behind the gunwale but I don't see a good way to drill and screw them in. Any ideas?

 

[Mike McCrea]

They are intended to be pop riveted in place between the inwale and hull with aluminum gunwales.

Can’t really do that with the much wider inwale section of vinyl gunwales. He could pop rivet them to the underside of the vinyl inwale, so that some of the D stuck out, but would probably need to use a right-angle drill attachment to drill the pop rivet holes.

https://www.harborfreight.com/38-in...CsgXh9TMt06u92za0qZMKzjbUOv8UqpQaAvSyEALw_wcB

With that solution I might try to pop rivet them so that they could be spun 90 degrees hidden completely under the inwale when not needed.

Looking at some vinyl gunwale scrap I guess they could be slid against the inside of the hull and pop riveted from the outside, through the outwale, hull, D-ring and inwale. Sounds ugly, and with a vinyl gunwaled Royalex canoe would require 1" long pop rivets.

 

[Glenn MacGrady]

Can’t really do that with the much wider inwale section of vinyl gunwales.

Questions from the peanut gallery:

1. Dab it with epoxy on both sides, slide it between the inwale and hull, and clamp?
2. Any recommendations, Mike, for an alternative d-ring or attachment loop solution?

 

[Johnny 5]

Delete

 

[Paddlinhal]

I think the right angle drill is the best solution for this. I'm sure he'll be happy for the excuse to buy another tool! Thanks

 

[Mike McCrea]

“I think the right angle drill is the best solution for this. I'm sure he'll be happy for the excuse to buy another tool! Thanks”

There are times that a drill adapter is the right tool. Sometimes the only tool that will work.

“Any recommendations, Mike, for an alternative d-ring or attachment loop solution?”

I believe Glenn is asking a question to which he knows the answers, but it is worth a review. Here’s a variety of possible tie point solutions.

P4030002 by Mike McCrea, on Flickr

All were weight bearing tested affixed to wood, vinyl and aluminum gunwales.

P4030003 by Mike McCrea, on Flickr

FWIW the Northwater flange D-ring, pop riveted between aluminum gunwale and Royalex, failed at 151lbs (the plastic flange tore through)

P4090040 by Mike McCrea, on Flickr

Sticking with tie points attached to vinyl gunwales:

Webbing loops. A five or six inch length of 1” webbing, folded over, with a 3/16” hole melted through the ends for a pop rivet or machine screw end. For the shank ends of any appropriate machine screws that is my go-to; I already have a machine screw shank and don’t need to drill any more holes.

P4040017 by Mike McCrea, on Flickr

A vinyl gunwale pop riveted webbing loop held 80lbs before failure (pop rivet pulled through gunwale). A webbing loop screwed into a wood gunwale held 320lbs, essentially the same for one on a machine screw end.

Pop riveted nylon pad eye.

P4050002 by Mike McCrea, on Flickr

The pad eye held 163lbs before failure (pop rivet pulled through gunwale)

P4050004 by Mike McCrea, on Flickr

Nylon grommet strap (more useful for webbing) held 114lbs (pop rivet pulled through gunwale)

P4050014 by Mike McCrea, on Flickr

Plastic cable clamp. Caution: the white hardware store variety are flimsy and not sized for a 3/16” pop rivet, the black ones are thicker, tougher and accept a rivet (cable clamp broke at 41.4lbs)

P4050024 by Mike McCrea, on Flickr

The clear winners in the weight bearing experiment were webbing loops and pad eyes screwed into wood gunwales. The pop rivet head tore through the webbing at 320 lbs, and I gave up on adding weight to the pad eye at 300+ lbs, but the pad eye was bent like crazy.

P4100006 by Mike McCrea, on Flickr

This thread for the full experiment with vinyl, aluminum and wood gunwales:

Canoe Outfitting Attachment Weight Bearing Experiment

I am again reminded of an experiment I have too long procrastinated, and in cleaning up the shop shelves found the lengths of wood, vinyl and aluminum gunwale scrap I need to get started. This will involve sacrificing sundry pad eyes, webbing loops, grommet straps, gunwale tab D-rings and etc...

www.canoetripping.net

 

[pblanc]

I have used the plastic "P clips" that are designed to secure coaxial cable. These can be secured to the underside of most synthetic inwales with a single stainless steel screw. They are only large enough to accept paracord or fairly small diameter accessory cord. When not in use the can be rotated inward under the inwale so nothing sticks out.

 

[Glenn MacGrady]

I have used the plastic "P clips" that are designed to secure coaxial cable. These can be secured to the underside of most synthetic inwales with a single stainless steel screw. They are only large enough to accept paracord or fairly small diameter accessory cord. When not in use the can be rotated inward under the inwale so nothing sticks out.

Pete, you mean something like this screwed vertically upward from the underside of the vinyl inwale?

 

[pblanc]

More like this, Glenn.


The all plastic ones like this also come in black. I have found that some are thicker and stronger than others but they can sometimes break. If maximum strength is a consideration, then consider these vinyl-coated metal P clips made by 3 M:

 

[Mike McCrea]

Pete, do you know if the vinyl clad metal cable clamps/P-clips are aluminum or steel?

I’m thinking about rust. Some years back I used stainless steel webbing style “D’s” from Wenonah to back up spray cover snap rivets.

P2170545 by Mike McCrea, on Flickr

Those were the crappiest “stainless steel” I’ve ever encountered. That canoe did a single trip on salt water. The metal was so corroded I cut it out and ran Zing-it cord through the still attached plastic flanges.

P3200679 by Mike McCrea, on Flickr

I’ve used a variety of mini SS D-rings as spray cover snap “washers”. Even these cheap Chinese-made SS D-rings have proven rust resistant. One has seen screwed to a dock post in the Everglades for a couple years as an acid test, still barely blemished.

https://www.amazon.com/EXCELFU-Stai...nature+stainless+steel+d+rings,aps,683&sr=8-3

I like that the D is easier to feed line through than a cable clamp, especially with thicker cord. I’ve also used better quality 316 marine stainless mini D-rings. At 3x the cost.

 

[pblanc]

Mike, I believe that the metal in the 3M clips is "corrosive resistant plated steel". I too have had "stainless steel" corrode and rust quite quickly. I have found that the thicker plastic P clips have been strong enough for my needs. I also find good quality 3 mm nylon accessory cord to be strong enough for my needs and that is quite easy to feed through the P clips. The good thing about securing these with stainless screws is that it if very quick and easy to replace one if it broke. It would also be easy to replace a corroded metal P ring although it would get old if one had to do so repeatedly.

 

[Mike McCrea]

“Dab it with epoxy on both sides, slide it between the inwale and hull, and clamp?”

To answer Glenn’s question, I think an epoxy bond, even G/flex between a vinyl or aluminum gunwale, would eventually fail from the stress, torque and twist of the D-ring flange.

I could try that as a further experiment. I still have experimental pieces of vinyl and aluminum gunwale attached to scraps of Royalex, but I have no more of those Northwater flanged D-rings.

Mini SS D-ring, webbing loop and Northwater flanged D on aluminum gunwale/Royalex.

P4060004 by Mike McCrea, on Flickr

Question for Pete

“I have used the plastic "P clips" that are designed to secure coaxial cable. These can be secured to the underside of most synthetic inwales with a single stainless steel screw”

Why screws and not pop rivets?

Screws work great with wood gunwales and actually held the most weight, up to and over 300lbs. A self-tapping screw would probably work on aluminum gunwales, cutting threads into the metal. But the underside or inner edge of a vinyl gunwale is only 1/8” thick, and on most aluminum insert vinyl gunwales the bottom and inside edge of the inwale are naught but vinyl.

P4030006 by Mike McCrea, on Flickr

1/8” of unreinforced vinyl would not provide a lot of beef for screw threads to bite. My concern would be the screw pulling out after it wigglewobbled the drilled hole in the thin vinyl larger than the thread diameter, which would make replacing the screw in the same hole problematic.

In the weight bearing experiments it took 60 to 80lbs (depending on whether a fender washer was used) to pull a pop rivet through a vinyl gunwale, and that weight was suspended from a single pop rivet. With multiple attachment points spreading the load as on float bag lacing or a gear cage that is plenty, and the cable clamp/P clip itself broke at 41.4lbs.

I have yet to experience a pop riveted attachment pulling through a vinyl gunwale. That could be the same for screws, but I’ve never used screws in that application.

 

[pblanc]

Why screws and not pop rivets?

I have used stainless sheet metal screws to attach about a thousand nylon pad eyes (inchworms) to synthetic gunwales on a considerable variety of canoes. Never had a screw pull out.

A screw can be tightened to the degree desired unlike a pop rivet. By not quite tightening the screw as much as it possibly can be, the P clips can be rotated outward under the inwales when not in use. That way there is nothing sticking out to snag gear or break off or just make the gunwale uncomfortable to grab with the hand.

If a pop rivet in a hollow synthetic gunwale needs to be removed, as they sometimes do by drilling off the head, the interior portion of the rivet remains rattling around inside the gunwale and can be difficult or impossible to remove. I find that perpetual rattling to be quite annoying.

 

[Mike McCrea]

“I have used stainless sheet metal screws to attach about a thousand nylon pad eyes (inchworms) to synthetic gunwales on a considerable variety of canoes. Never had a screw pull out.”

I prefer pad eyes for a lot of applications. Having two pop rivets (or screws) holding the attachment rather than just one more than doubles the strength by decreasing any twist or wooblewobbly wear on a single drilled hole.

Pad eye weight bearing capacity is overkill for most things, but I use Surf-to-Summit back bands, with swivel clips attached to pad eyes, in most of our boats. I don’t lean back Barcalounger sprawled against the back bands, but do use it for minor oppositional force in conjunction with a foot brace. Even with all of the weight carried by the front straps attached to a pad eye on either side I probably could recline; a single pad eye pop riveted to a vinyl inwale held 163lbs before one of the two rivets pulled out of through the 1/8” thick vinyl.

P4080007 by Mike McCrea, on Flickr

“A screw can be tightened to the degree desired unlike a pop rivet. By not quite tightening the screw as much as it possibly can be, the P clips can be rotated outward under the inwales when not in use. That way there is nothing sticking out to snag gear or break off or just make the gunwale uncomfortable to grab with the hand.”

Pop riveted cable clamps can be rotated under the inwale, although it does require a little more finger ouchie, at least for the first few times. I suspect some rivet head wear against the plastic cable clamps makes repeated rotations easier.

If a pop rivet in a hollow synthetic gunwale needs to be removed, as they sometimes do by drilling off the head, the interior portion of the rivet remains rattling around inside the gunwale and can be difficult or impossible to remove. I find that perpetual rattling to be quite annoying.

I have needed to drill out pop rivets in vinyl gunwales when soloizing a tandem. After the head is drilled off I punch the remains of the rivet pin loose into the inwale channel, and the rattle of the smushed mandrel and pins is annoying. Enough so that I’ve stood some canoes on end and thumped on the gunwales, so the loose mandrel heads cascaded out the open ends of the inwale channel.

The disgorgement sound was reminiscent of a cactus rainstick, satisfying because the dang mandrel heads were finally gone.

FWIW, the synopsis of the weight bearing experiment results, something I had long wanted to do just to satisfy my own curiosity. That was the most fun and most revelatory experiment yet. And the most strenuous; I picked up and restacked a couple thousand pounds of weights from the shop floor after the clang-bang-smash crashing down failures.

Attachments, Failure Weights, How Failed and Suppositions as to why things failed from that experiment:



Nylon webbing pop riveted through vinyl gunwale, 30lbs

Webbing pulled through 3/16” rivet head



Nylon webbing with fender washer pop riveted through vinyl gunwale, 60 lbs

3/16” Rivet pulled out of vinyl gunwale



Poly webbing pop riveted through vinyl gunwale, 70 lbs

Webbing pulled through 3/16” rivet head



Poly webbing with fender washer pop riveted through vinyl gunwale, 80 lbs

3/16” rivet pulled out of vinyl gunwale



Thoughts and suppositions:

Webbing loops need a washer under the pop rivet. OK, I already knew that.

Thin nylon webbing will pull through a washer more easily than thick poly webbing. No surprise there either.

3/16” pop rivets through thin (1/16” thick) vinyl gunwale will pull through the gunwale between 60 and 80lbs. The thicker/sturdier the webbing the more weight it held, perhaps because the weight was less likely to pull sideways, bending and sheering the pop rivet.



Grommet strap pop riveted through vinyl gunwale, 114 lbs

3/16” rivet pulled out of gunwale



Thoughts and suppositions:

OK, not a fair comparative test, the weights were pulling on the grommet strap sideways, not straight down. It definitely takes more weight to pull a pop rivet from a vinyl gunwale in that orientation. I am still impressed that the grommet strap itself held 114lbs



Nylon pad eye with dual pop rivets through vinyl gunwale, 163lbs

One of two 3/16” rivet pulled out of gunwale.



Thoughts and suppositions:

Two pop rivets are better than one. And I’m more a fan of those nylon pad eyes than ever; those are where my swivel snap Surf to Summit back bands are attached.



Weird plastic webbing connector (no pop rivet, hung via webbing), 95 lbs

Plastic broke



Thoughts and suppositions:

I dunno, whatever that skinny thingamadoodle was made of it held an impressive amount of weight. I only used it because I had one in the parts box. The type of plastic, nylon, derlin, etc obviously makes a strength difference.



Plastic Cable clamp pop riveted through vinyl gunwale with 3/16” pop rivet, 41.4lbs

Plastic clamp broke



Thoughts and suppositions:

Way more weight than I thought one of those would hold. The elongation before failure should have been no surprise.



Spray cover stud and mini SS D-ring pop riveted through Royalex sheet with 1/8” pop rivet, 124.5lbs

Rivet broke



Spray cover stud and webbing loop with 1/8” pop rivet on Royalex sheet, 171.5lbs

Rivet broke



Thoughts and suppositions:

Wow! A lot more weight than I would have predicted using a 1/8” pop rivet. Backing up spray cover studs is now a given.



Mini SS D-ring with 1/8” pop rivet affixed to aluminum gunwale, 82.5 lbs

Rivet broke



Webbing loop with 3/16” pop rivet on aluminum gunwale, 55 lbs

Rivet broke



Thoughts and suppositions:

Note the reduction pop rivet failure weights. I believe the aluminum gunwale helped sheer the aluminum pop rivet. And that was pulling straight down; pulling sideways might be even worse.



I tried using 3/16” steel pop rivets once. That was a nope with my hand pop rivet gun; I couldn’t even begin to squeeze them closed. I have a box of 24 left, 3/16” dia X 3/8” long, large flange steel. Free to good home.



Under-inwale D ring plastic tab with 3/16” pop rivet, 151lbs

Plastic tab tore.



Thoughts and suppositions:

Again, seriously stronger than I would have thought. A decent solution for under aluminum gunwales.



Eye screw in wood gunwale, 76.5lbs

Eye screw hole straightened out (long before weight limit was reached)



Thoughts and suppositions:

The eye screw loop straighten out, probably starting at 50lbs or so. Kinda predictable.



Cable clamp screwed in wood gunwale, 51.5 lbs

Plastic clamp broke



Thoughts and suppositions:

The elongation was comical to behold, but even those winky attachments held more weight than I anticipated.



Webbing loop screwed in wood gunwale with cup washer, 282.5 lbs

Webbing tore through cup washer



Webbing loop screwed in wood gunwale with flange washer, 320 lbs

Webbing tore through flange washer



Thoughts and suppositions:

Those both held a lot of weight. Flange washers helps. Better webbing would have helped as well. Dabbing epoxy in the screw holes made no difference, except that I couldn’t back the screws out when done.



Pad eyes screwed in wood gunwale (with smaller screw heads), 146 to 157 lbs

Screw heads pulled through nylon pad eyes



Pad eye screwed in wood gunwale (with larger screw heads), 300+ lbs

Nothing failed, I just gave up, although that pad eye was bent like crazy.



Thoughts and suppositions:

Size does matter, at least when it comes to screw heads in nylon pad eyes. Again, nylon pad eyes, with two pop rivets or screws, will hold a tremendous amount of weight. Also Mike will give up at 300lbs weight and call it good.

 

[Glenn MacGrady]

Dab it with epoxy on both sides, slide it between the inwale and hull, and clamp?

To answer Glenn’s question, I think an epoxy bond, even G/flex between a vinyl or aluminum gunwale, would eventually fail from the stress, torque and twist of the D-ring flange.

I could try that as a further experiment. I still have experimental pieces of vinyl and aluminum gunwale attached to scraps of Royalex, but I have no more of those Northwater flanged D-rings.

Would you do the weight bearing experiment if some Northwater flanged D-rings magically appeared or if you had some reasonable facsimile?

 

[Mike McCrea]

“Would you do the weight bearing experiment if some Northwater flanged D-rings magically appeared or if you had some reasonable facsimile?”

Glenn, I need to get up to Blue Mountain Outfitters soon to pick up some outfitting bits and pieces. BMO stocks a lot of Northwater stuff and I’ll pick up a few of those flanged D-rings and try G/flexing them between aluminum gunwale and vinyl gunwale sections and RX sheets.