Self-fendering gunwale treatments for tenders

2airishuman

Anarchist
I am planning an upcoming scratch build of a Chameleon dinghy.

One of the questions I am pondering is the best gunwale treatment.  It seems to me that nearly all hard dinks built as tenders have some sort of self-fendering gunwale treatment.  Among these are:

  1. Foam covered with fabric; everything from pool noodles covered with firehose, to more special-purpose materials sold already made up by chandleries, to bespoke combinations.  These are mechanically fastened, with screws and washers, or monel staples, or with the fabric being folded behind a batten that is then screwed down.
     
  2. Elastomeric tubing of various kinds that provides cushioning and a sliding surface in a single material.  Includes things like PEX tubing from the home center as well as the fancy EPDM extrusion used on the PT-11. 
     
  3. Non-marking, low friction treatments that do not provide cushioning.  The usual homemade version is polyethylene water pipe cut in half and fastened with screws so that it is mushed down into sort of a U channel shape.

I am leaning towards trying a variation of #3 by applying a 1/4" piece of solid ultra-high molecular weight polyethylene (UHMWPE) bar.  Same molecule as used to make Dynema but in solid bar form rather than little strands.  The stuff is slippery, non-marking, tough, easy to keep clean, relatively inexpensive, and does not add much weight or bulk.  Epoxy will not adhere to it well so it must be fastened mechanically.  I am planning on through-bolting it with 316 stainless flathead machine screws that are countersunk into the UHMWPE bar, going into 316 stainless tee nuts on the inwale.

The obvious disadvantage is that it doesn't provide cushioning.  But I'm not sure that the cushioning provided by the other treatments is sufficient to make much difference in the event of a hit serious enough to damage the boat, and the UHMWPE bar provides a degree of additional strength to the gunwale system that the softer products do not.

So my questions are, what you all think of that, and what sort of experiences have you had with other self-fendering materials on tenders.

 
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Zonker

Super Anarchist
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Canada
Having had a few hard dinghies over the years for full time living aboard (~16 years total)...the biggest issue is coming alongside when a good swell or big wind waves are present (18" and above). The dinghy is moving up and down while you unload people or groceries and as the boat veers at anchor, is also coming in sideways as well.

1. I think 1/2 biggest pool noodle you can find (5" diameter are available), covered with fabric THAT IS NOT SUNBRELLA is the nicest looking option. Sunbrella has good UV resistance but is shitty for chafe resistance. I would use Topgun or some other marine type fabric instead. The thread about catamaran dinghies being built has a nice example.

I've also used strips of EVA foam that is laced which is very practical but not as attractive. No cover used; EVA is pretty UV stable. I've also recently seen the install method for some EVA flotation cushions on an Aussie system. They slit the very thick EVA foam on the underside, about middle of the fender thickness and insert a alum. backing plate into the fender. Then they screw into backing plate from inside the hull. Tidy installation but mechanically strong. No direct experience.

2. The nice EPDM fender like the PT11 is too small for any significant swell to provide cushioning in big waves when coming alongside the mother ship. OK for sheltered waters with little waves. PEX tubing has no cushioning effect for a big hit. 

3. You won't be popular when visiting other boats with #3....I think that you can easily scuff paint or gelcoat with a hard hit from UHMW. Fenders are to protect the big boat from cosmetic marks and actual structural damage to the dinghy. UHMW will really be a big "bang" when you hit.

 

andykane

Member
427
192
Victoria, BC
I've been thinking about the very same thing for a hard tender - trying to combine the positives of an inflatable with the benefits of a hard tender.

As a variation of #3, in the past I've had several small tenders with unpainted red cedar gunwales. This is soft enough to generally avoid damage to the mothership during a quick boarding and very easy. UHMW bar sounds like a great way to protect the dinghy but I would rather a solid wood gunwale which would be lighter, and avoid all the fasteners. I wouldn't expect it to provide any extra strength either - it's very flexible compared to the plywood of the hull.

I've been leaning toward some kind of foam fendering, something good enough to eliminate the need for dinghy fenders. I figure go big or do nothing (and use separate fenders).

 

gwilcox

New member
22
4
seattle
On my chameleon I tried the fire hose with pipe insulation method.  It worked OK for a year of Pacific cruising and then fell apart due to rot.  Cotton hose really isnt the best idea.  I next used the fancy, much more expensive version from the chandlery.  stapled on with screws at the ends it worked well and lasted several years.  Its still OK in fact but not in use at the moment.

I strongly recommend the cushioning if you are going to be in any anchorage with chop.  Also, the chameleon has a lot of flair.  this means you want to have fendering on the top as well as the outboard side.  So wrap it around the corner.  This limits the amount of cushioning if the oars are to be usable.

I used the Taylormade 3/4 round version.

taylormadeproductdockguard-v1-1000x1000.jpg

 

SloopJonB

Super Anarchist
65,079
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Great Wet North
1. I think 1/2 biggest pool noodle you can find (5" diameter are available), covered with fabric THAT IS NOT SUNBRELLA is the nicest looking option. Sunbrella has good UV resistance but is shitty for chafe resistance. I would use Topgun or some other marine type fabric instead.
Back in the early 90's I was talking about getting some dock edging because the wood decking beside my berth was old & rough. A few days later my wife came home with some pool noodles. I installed them and pretty soon they were popping up all over the marina - should have patented her idea. :D

I soon learned how essential a sleeve is though - they crumble quickly from UV even here.

 

gkny

Member
335
25
Garden hose is made to sit out in the sun forever.  On an old dinghy I screwed it to the rails with small washers.  The dimpling around the washer protected other surfaces

 

Bristol-Cruiser

Super Anarchist
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1,134
Great Lakes
On my chameleon I tried the fire hose with pipe insulation method.  It worked OK for a year of Pacific cruising and then fell apart due to rot.  Cotton hose really isnt the best idea.  I next used the fancy, much more expensive version from the chandlery.  stapled on with screws at the ends it worked well and lasted several years.  Its still OK in fact but not in use at the moment.

I strongly recommend the cushioning if you are going to be in any anchorage with chop.  Also, the chameleon has a lot of flair.  this means you want to have fendering on the top as well as the outboard side.  So wrap it around the corner.  This limits the amount of cushioning if the oars are to be usable.

I used the Taylormade 3/4 round version.

View attachment 370516
I made my Chameleon with the 3/4 round stuff. Not cheap but does a very nice job and looks good.

 

Kris Cringle

Super Anarchist
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2,173
I made my Chameleon with the 3/4 round stuff. Not cheap but does a very nice job and looks good.
And it lasts. I think of this stuff as a consumable item for sailing, like batteries. They don't last forever and neither does this dinghy fender. But I do get 10 years out of it and the dinghy is a tender or at a dinghy dock 5 months out of the year. The rest of the year, the dinghy stays outdoors, with a tarp. 

It really works well for what we need and the dinghy is always towed. 

I've recently installed the 3 rd fender on my 25 year old Nutshell. Today, the stuff costs about as much as the materials did, to build it. 

EVE new fender.jpg

 

cyclone

Super Anarchist
1,301
568
Maine
A cheap alternative is 3-strand rope. Mill ends can be had cheap at the local marine supply. 1 1/2” works well. Open the strands and drive a screw and cup washer through the inner strand into the gunwale.

 

dylan winter

Super Anarchist
6,535
1,798
I just string a few small fenders around the outside of the tender

the tender is simulated clinker - no bouyancy

so the fenders give it bouyancy

I have towed the fender for 1000 miles with no problems

Dylan

 

Zonker

Super Anarchist
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Canada
I've tried large dia 3 strand rope. Cushioning effect was minimal unfortunately. Was useful as a cat recovery device, hung over the stern with knots in it.

The few small fenders are practical, but rather ugly (and kind of costly when you need 4 or so fenders each side?)

 

Zonker

Super Anarchist
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Canada
Not me. My wife liked the huge orange devil-beast.  He was a tough SOB.

One day I gave a friend a piece of plywood to cut a piece for himself. He returned it, propping it on the side deck alongside the lifelines, right where the cat recovery rope was tied.

Naturally that night, the cat falls overboard. He tries to self rescue, as he has done many times in the past, but this time there is a 12" high smooth barrier at the top of  the rescue rope. He tries repeatedly to get past the smooth barricade and fails.
 

We found him floating alongside the boat the next morning when he didn't appear for breakfast. Many of his claws were ripped out. One claw was still hooked into the rescue rope and that was what saved him from drifting away.

He was deeply hypothermic but  a friend in the anchorage was a vet. She came aboard and supervised the re-warming. She told us later that the she didn't think he was going to make it, based on his temperature when she arrived.

Of course he was back to normal later that evening, stealing rum drinks and causing trouble.

 

Jud - s/v Sputnik

Super Anarchist
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Canada
I used the Taylormade 3/4 round version. View attachment 370516
I’m under the impression that stuff like that (or foam covered with firehose material) would be slightly abrasive on a painted hull (I.e., the mothership’s), after several rubs.  (I’ve seen firehose material, but I’ve never seen the Taylormade product, so it’s just my impression.)  Is the polyester fabric on the Taylor made product more or less like the cotton firehose material?  (I.e., relatively loose weave, so slightly abrasive?)

I’m thinking that for a painted hull (as opposed to a fibreglass gel coat hull), where the dinghy might rub up and down against the mothership occasionally, a smooth “rubber” type gunwhale cove (like garden hose type material, noted by someone else in this thread) might be better?  (I’m almost at the stage of finishing my Two-Paw 8 build, and am now turning my attention to finishing details - have been so busy with the build, I totally forgot about fendering! :).

Keel and deadwood on, and daggerboard trunk hole cut:

2C15640D-634D-4363-AE41-1D0DBEEBE82D.jpeg

 
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