Why are my inflatable fenders going flat?

[coopec43]

I'm using inflatable 700mm X 240mm fenders recommended by the marina boat shop but the second one has just gone flat. (Mind you in its' flat state it is still providing protection)

I am wondering if I am being sold fenders suitable for a 3 tonne launch rather than an 11.6 tonne yacht?

Would a 690mm X 300mm cushion be a better proposition or maybe a tear drop fender?

[Mike OReilly]

They do look a little small for the size of your boat.

I use these inflatable fenders:

https://www.easystowfenders.com/fd_hd.html

I think I have the heavy duty, 12" Dia. x 44" (304.8mm x 13411.2m) versions. They work great, are incredibly strong and tough, and can be deflated and stowed in a fraction of the space that normal fenders occupy.

Oh, and they don't deflate under pressure.

[Montanan]

I'm not sure, perhaps it is just a down-under thing.

[deblen]

I have patched pvc fenders and "teardrop" floats using vinyl pool repair cement.
This cement melts & welds the pvc.
Cheers/Len
https://www.homedepot.com/p/HDX-Swim...2280/203796269

[coopec43]

Originally Posted by deblen

I have patched pvc fenders and "teardrop" floats using vinyl pool repair cement.
This cement melts & welds the pvc.
Cheers/Len
https://www.homedepot.com/p/HDX-Swim...2280/203796269

Thanks for that but I am certain my two are leaking through the valves. (both are quite new) i

[NevilleCat]

Looks like they are the Majoni ones.? If so you can get new valves from Whitworths etc for $11 or so.
You will need the little adapter with the tiny screw thread for those valves. Don't try to pump them up with a soccer ball needle or you will wreck the valves. They are just pressed into the fender and held in by luck so you can pull them out with the adapter if you need to replace them.
I guess do the soapy water test to see if that is where they leak from, whether it's the valve or from around the outside of the valve.

Also to watch: chandleries will sell you pre made fender lines with a loop spliced at one end; most people will feed the loop through the fender and the tail back through the loop which seems logical however if you get in a rough situation where the fender is getting pulled down or squeezed while the boat is rolling, that loop can tighten on itself so much that it cuts into the hole in the fender (which, bizarrely is part of the inflatable structure not solidly reinforced) so can cause leaks there. Even just the weight of the larger fenders can cause this.
Better to tie the fenders on.

[coopec43]

NevilleCat

Thanks for your post as you have provided very valuable information which I intend to follow up.

I'm not having much luck with fenders as one of the ropes did cut through the PVC end attachment hole. I was mortified when it disappeared as I read they can be a real hazard if the rope gets caught up in someone's propeller.

[thinwater]

Also, tying the boat in such a way that it does not constantly bear on the fenders helps. It is tempting to lean on fenders with floating docks, but there is a center dolphin in the back, so perhaps bow lines, stern lines, and springs could be put to better effect. Can't say without seeing it.


I've never tied a boat in such a way that I needed fenders, unless on a bulkhead.

[rslifkin]

Originally Posted by thinwater

Also, tying the boat in such a way that it does not constantly bear on the fenders helps. It is tempting to lean on fenders with floating docks, but there is a center dolphin in the back, so perhaps bow lines, stern lines, and springs could be put to better effect. Can't say without seeing it.


I've never tied a boat in such a way that I needed fenders, unless on a bulkhead.

I agree, I always try to keep the fenders from touching given the choice. But in a slip without adequate pilings or cleats on the off-side or on a face dock, there's typically no choice (unless the wind happens to be in a convenient direction to keep the fenders un-loaded).

[VChild]

Originally Posted by coopec43

I'm using inflatable 700mm X 240mm fenders recommended by the marina boat shop but the second one has just gone flat. (Mind you in its' flat state it is still providing protection)

I am wondering if I am being sold fenders suitable for a 3 tonne launch rather than an 11.6 tonne yacht?

Would a 690mm X 300mm cushion be a better proposition or maybe a tear drop fender?

Your fenders do look a little on the small side for your boat but did you have any severe storms recently? A few weeks ago, a severe system passed through my area with gusts recorded at 63mph. The forces were so strong that one of the dock cleats securing my boat sheared off with my dock line still attached. The remnants of the 12" cast aluminum cleat were still bolted to the aluminum dock. This caused my boat to shift over to the finger pier on my port side. I had appropriately sized large fenders hanging on that side but the compression on the fenders all night caused them to deflate (either through the valves or by rupturing). My fenders were fairly new and in great shape but were no match for the power of mother nature. My solution was to fabricate a dockside system to hold a very large fender on the finger pier and also replace the crappy cast aluminum cleats with heavy duty galvanized iron cleats. Perhaps your marina will allow you to install a fender system like mine. Although I did mine myself, a fab shop wouldn’t charge much to create a system like mine. I used quarter inch thick aluminum and the system holds the largest TaylorMade fender from West Marine - 34” long by 12” diameter.

[coopec43]

Originally Posted by thinwater

Also, tying the boat in such a way that it does not constantly bear on the fenders helps. It is tempting to lean on fenders with floating docks, but there is a center dolphin in the back, so perhaps bow lines, stern lines, and springs could be put to better effect. Can't say without seeing it.

I've never tied a boat in such a way that I needed fenders, unless on a bulkhead.

It is a floating dock but I can only have starboard/port bow lines and a port stern line (plus springs).

Maybe one of the problems is one fender is currently taking 75% of the load and the other 25%.

[coopec43]

VChild


Thank you for your advice



I think you have confirmed my belief I should be trying to balance up the loads on the fenders more equally.

[rslifkin]

Originally Posted by coopec43

It is a floating dock but I can only have starboard/port bow lines and a port stern line (plus springs).

Maybe one of the problems is one fender is currently taking 75% of the load and the other 25%.

On the stbd side, try running a spring line forward to the same dock cleat the stbd bow line attaches to. If the bow is held off the dock by the bow lines and you crank that new spring line plus the aft spring on the port side good and tight, it should pivot the stern off the dock. It may still touch in strong winds, but it won't sit against the fenders all the time that way. It does mean the boat has to be tied pretty tightly though, this doesn't work with any meaningful slack in the lines.

[coopec43]

Originally Posted by rslifkin

On the stbd side, try running a spring line forward to the same dock cleat the stbd bow line attaches to. If the bow is held off the dock by the bow lines and you crank that new spring line plus the aft spring on the port side good and tight, it should pivot the stern off the dock. It may still touch in strong winds, but it won't sit against the fenders all the time that way. It does mean the boat has to be tied pretty tightly though, this doesn't work with any meaningful slack in the lines.

Thanks. I will definitely try that

[deblen]

Originally Posted by VChild

Your fenders do look a little on the small side for your boat but did you have any severe storms recently? A few weeks ago, a severe system passed through my area with gusts recorded at 63mph. The forces were so strong that one of the dock cleats securing my boat sheared off with my dock line still attached. The remnants of the 12" cast aluminum cleat were still bolted to the aluminum dock. This caused my boat to shift over to the finger pier on my port side. I had appropriately sized large fenders hanging on that side but the compression on the fenders all night caused them to deflate (either through the valves or by rupturing). My fenders were fairly new and in great shape but were no match for the power of mother nature. My solution was to fabricate a dockside system to hold a very large fender on the finger pier and also replace the crappy cast aluminum cleats with heavy duty galvanized iron cleats. Perhaps your marina will allow you to install a fender system like mine. Although I did mine myself, a fab shop wouldn’t charge much to create a system like mine. I used quarter inch thick aluminum and the system holds the largest TaylorMade fender from West Marine - 34” long by 12” diameter.

This is just an observation on my part regarding the dock fingers pictured.
I live in a 20ft tidal area & I have seen this happen with a damaged dock that has an unintended piece of timber,etc sticking out a bit.This makes a situation like your dock.The deck of your dock,with no "apron"/or "wood fender" pilings going down,preferably into bottom aways,is creating a situation where your boat & it's fenders can dive down low enough to catch on the underside of that dock deck.This could happen if 2ft or more seas hit your docked boat.
The first damage done by a bouncing boat will be tearing the eyes out of your fenders as they catch on the underside of dock while boat is rising rapidly.
The vertical fender mounted in a metal tray is a nice,but expensive,solution.
Perhaps those docks should have several driven 3x6,s to make an apron to lay center fenders against.
Just my humble opinion.
Cheers/Len