We recently spoke about why my dinghy deflates by itself so thanks for some of our reader today we’ll face another important lesson: what pressure to keep on a dinghy?
First important thing to understand is that dinghies AT SEA are different to TENDER ONBOARD or rhibs ON LAND.
Most of you would think “because of the temperature”.. well.. yes and no!
The temperature plays the game, but the real answer is because OF THE WATER, which works as temp dissipator.
The fabric of the tubes, in fact, once they are even partially immerged begin to exchange heat, leading to a LOWER temperature.
x2 the temperature = x2 the pressure
1/2 the temperature = 1/2 the pressure
This is the basic rule, which is repeated and repeated in order to understand that the temperature CHANGES COMPLETELY YOUR VESSEL’S PLANING.
During autumn we see a strong drop of temperatures, and is REALLY IMPORTANT that when you will get onboard to move your rhib, or jump on a tender YOU REMIND TO INFLATE IT or bigger issues will occur.
START FROM ASTERN, so u will give full pressure on the planing surface, then proceed ahead.
WHY SHOULD I INFLATE FROM ASTERN AND NOT FROM AHEAD?
Inside the tube there is a BAFFLE or DIAPHRAGM, which moves ahead/astern accordingly to the section u inflate first.
When u inflate bow-to-stern, the planing compartment is the one which is subject to the highest temp gap, cause its pressure is directly depending from the 1,2,3 ahead..
While if u start astern, the diaphragm moves ahead, and that very compartment is a leading one now.
In this way it us subject to temp gap, but much much less, and is easier to inflate cause will keep a higher volume.
That is a planing surface so MUST be kept hard anytime using the rhib.
KEEP TUBES ASTERN 0,20bar AT ALL TIME
Almost every tube producers indicate the 0,2 bars (approx 3 psi) as standard pressure, but we have several exceptions and you can take this as guideline:
– standard dinghy / rhib AT SEA
0,2/0,25 bar astern, 0,2 ahead (where the sun heats more and there is no heat dispersion effect from the water).
– T/T dinghy / rhib OUT OF THE WATER
0,17 / 0,2 bar overall. This will reduce heat deformation on PVC dinghies and explosions.
On Hypalon© devices will make almost no difference.
– Racing dinghies/TOPCAT
0,7/0,8 bar overall, these devices are closed with welding technique, granting the maximal pressure. PVC is anyway a short-term choice, to read the differences with hypalon read difference between pvc and hypalon.
up to 1bar / 14psi, SUPs are devices which reach incredible pressure since are not subject to very heavy stress. To extend your SUP life read how NOT to store your SUP.