How can I keep it hard longer?

Oct 1, 2007
1,856
Boston Whaler Super Sport Pt. Judith
Hi all:
I have a 10 ft AB inflatable about 12 years old. It has been trouble free but has always seemed to be temperature sensitive. Whenever the temperature drops, the tubes soften. Of course the density of the air inside will decrease with lower temperature, which will tend to soften the tubes, and vice versa. However, the dinghy next to mine on the dinghy float is a brand new AB, same model as mine. I noticed that his dinghy seems to be less temperature sensitive than mine such that his stays hard and mine softens.
So, the question is am I doing something wrong here? Maybe I don't pump it up enough initially? How hard should it be? Or is there something else? How do you maintain your inflatable?
I'd appreciate your thoughts.
Thanks
Rick
 
Last edited:

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
I don't recall the exact figure for AB inflatables (I have one, the VS9), but the tube pressure should be 2.5 to 3 psi. You need a special gauge for this.

Age makes a difference. the fabric seems to become less elastic, and also develops otherwise undetectable leaks. Naturally, the more elastic, the less susceptible to the phenomenon you describe.
 
Feb 10, 2004
3,917
Hunter 40.5 Warwick, RI
Just a thought- perhaps in hot weather the air expands and pressure rises. The increased pressure causes some air to leak past the cap gaskets. Then as the temperature cools, the boat becomes soft.

When was the last time you replaced/cleaned the o-rings or gaskets at the cap?
 
  • Helpful
Likes: ggrizzard
Apr 8, 2010
1,942
Ericson Yachts Olson 34 28400 Portland OR
We finally decided to junk our great old Zodiac after about 20 years due to near-undetectable seam leaks. dealer said that there was a way to put a liquid sealant inside and slowly rotate the inflated boat for a number of hours to allow the thin sealant to be drawn into the tiny leaking areas, but that it was sometimes ineffective.
The scheme seemed too unreliable (kind of like the fix-a-flat stuff you inject into your flat tire to get you home... and then throw away the tire).
We bought a new dinghy instead.
Whether we made the 'right' decision is another discussion. Inflatable Dinghies have a lot of advantages, but also a limited useable life. This opinion worth only 2 cents on a good day! :)

ps: as Rich points out, do check on the valves and caps!
 

capta

.
Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
On a hot tropical sunny day our Zodiac is about as hard as a basketball and it stays hard at night, even in the winter. But we don't have the temperature changes you have up there.
I firmly believe that keeping an inflatable hard is the reason we get such a long life from ours. An under inflated dinghy will flex when in use which I think is very bad for the seams.
 
Jan 19, 2010
12,362
Hobie 16 & Rhodes 22 Skeeter Charleston
It is all I can do not to let my inner 13 year old out.:oops:




But on a serious note. Pressure (P) and temperature (T) can be related by the equation

PV=nRT. V= volume (constant) and if you don't have a leak then n (number of moles of gas) is a constant (and R is the "gas constant") so... P = cT where c is the combined constants. You should expect the pressure to change with temperature so if you do not have a leak then I suggest you fill it firm on a cool day. It should get ridiculously hard around noon but then "soften" back up to just plain old hard in the evening. If that does not happen and it gets soft again, then you have a leak.
 
Jun 11, 2004
1,621
Oday 31 Redondo Beach
Hi all:
I have a 10 ft AB inflatable about 12 years old. It has been trouble free but has always seemed to be temperature sensitive. Whenever the temperature drops, the tubes soften.
If it softens when it's cold does it re-harden when it warms back up?
If so it is probably just underinflated from the start.


FastOlson said "dealer said that there was a way to put a liquid sealant inside and slowly rotate the inflated boat for a number of hours to allow the thin sealant to be drawn into the tiny leaking areas."
I did that once with an old Achilles and it worked very well to cure slow leaks.
 
Last edited:
  • Helpful
Likes: jssailem

Bob S

.
Sep 27, 2007
1,771
Beneteau 393 New Bedford, MA
Just have to get used to it soft, just don't jump into it to quickly!
 
Oct 26, 2008
6,041
Catalina 320 Barnegat, NJ
I'm guessing that nobody actually ever puts a gauge on the inflation. I've been wondering about it. How are you supposed to know how inflated it should be? My brand new Zodiac labels the chambers from 3.5 psi to 11 psi for the air floor. How are you supposed to know without over inflating?
 
Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
On my boat, Scott, the valve and the pump do not have a way to install a gauge. I suspect it could be engineered.
 
Jun 11, 2004
1,621
Oday 31 Redondo Beach
I'm guessing that nobody actually ever puts a gauge on the inflation. I've been wondering about it. How are you supposed to know how inflated it should be? My brand new Zodiac labels the chambers from 3.5 psi to 11 psi for the air floor. How are you supposed to know without over inflating?
Something like these?


 
  • Like
Likes: Scott T-Bird

dLj

.
Mar 23, 2017
3,370
Belliure 41 Sailing back to the Chesapeake
Way over-thinking things here. But hey, toys are fun!

You could also use like a basket ball, pump it up. Use a tire gauge on the needle valve and put it in and feel how it feels at 3 psi, pump it up to 11 psi and feel that. It will be noticably different. Then you have calibrated you hand... No more gauge needed...

dj