Easy Question : Recommended inflatable pressure?

[wipe_out]

Just picked up my first inflatable that will be used as a tender on our boat when we move to a swing mooring.. Picked it up used and really happy because both the outboard and the boat are in excellent condition.. Just have to work out how best to roll it up into the bag..

Anyway, the included manual says pump till it "feels" hard but don't over inflate it.. In my world that is of no use at all because I have no point of reference as to how hard "feels" right.. So I plan on picking up a pressure gauge until a get a "feel" for how hard I should inflate it.. The issue is that the manual doesn't specify a pressure anywhere either..

The boat is a WavEco 2.6m.. So essentially the same as all the other budget inflatables I would think..

What sort of pressure should I be inflating it to?

Thanks..

 

[epervier]

Just picked up my first inflatable that will be used as a tender on our boat when we move to a swing mooring.. Picked it up used and really happy because both the outboard and the boat are in excellent condition.. Just have to work out how best to roll it up into the bag..

Anyway, the included manual says pump till it "feels" hard but don't over inflate it.. In my world that is of no use at all because I have no point of reference as to how hard "feels" right.. So I plan on picking up a pressure gauge until a get a "feel" for how hard I should inflate it.. The issue is that the manual doesn't specify a pressure anywhere either..

The boat is a WavEco 2.6m.. So essentially the same as all the other budget inflatables I would think..

What sort of pressure should I be inflating it to?

Thanks..

To be honest I've yet to see a dinghy pump with a pressure gauge fitted to it, rule of thumb for me has been push your hand on the tubes, if the tubes give under the weight of you pushing, pump some more until it supports your weight, ie the tubes aren't saggy, sorry to be so vague or another test is if you have the built in pin type rollocks the tubes should be hard enough for you to row the boat without them folding into the tubes.

 

[CaptainMike1970]

Try the "rule of thumb"

Push down the tube with your thumb, if the tube deflects much more than the depth of your thumb nail add more air.

 

[[2068]]

My cheap rollup tender says "0.25 bar or 3.6 PSI" on the sticker.

 

[landlockedpirate]

If you use the original pump, it will pump till it wont go any further.

The best investment I ever made for using the dinghy was one of these http://www.ebay.co.uk/itm/Bravo-Inflatable-Boat-Rib-Kayak-12v-Air-Pump-Electric-Inflator-High-Pressue-BP12-/111352797923?pt=UK_Sporting_Goods_CanoesKayaks_Rafts_SM&hash=item19ed24dae3

Plug it in, set the pressure and have a brew while it does the hard work and auto cut off means its perfect every time.

 

[[2068]]

If you use the original pump, it will pump till it wont go any further.

That's not great advice.

(remember the scene with the "wafer thin mint" ?)

.

 

[rosssavage]

2.5 - 3.5psi is usual. 5-6psi for the inflatable floor if it has one

 

[wipe_out]

Great!! That's something I can work with..

 

[wipe_out]

That's not great advice.

(remember the scene with the "wafer thin mint" ?)

.

Haha.. That scene came up in discussion at dinner last night coincidentally..

 

[wipe_out]

The best investment I ever made for using the dinghy was one of these http://www.ebay.co.uk/itm/Bravo-Inflatable-Boat-Rib-Kayak-12v-Air-Pump-Electric-Inflator-High-Pressue-BP12-/111352797923?pt=UK_Sporting_Goods_CanoesKayaks_Rafts_SM&hash=item19ed24dae3

Yes, I had a look at these but it blows up pretty quick with the foot pump anyway so all I really need is a pressure gauge.. And roughly the right pressure..

 

[Tranona]

Great!! That's something I can work with..

It really is not critical. With a footpump you cannot overpressurise it. Just pump until it gets hard work then flick the tube with your finger nail. If it pings it is hard enough. You will soon find out what happens if you underinflate.

Note that this procedure only applies to basic inflatables such as yours. More sophisticated boats may need more accurate pressures, but the handbook will say so and the pump provided will have a pressure gauge.

 

[landlockedpirate]

That's not great advice.

(remember the scene with the "wafer thin mint" ?)

.

Just one more ?

But the OP has the base model, slat dinghy (no high pressure floor). The original pump cant over pressure the tubes, its not possible, the pump gives up a long way before you damage the tubes.(Especially with the pump that comes with that boat ). The exception to this is a pump that does the floor as well, then you can go way past a wafer thin mint.

 

[[2068]]

The pump that came with mine is some sort of general purpose red cylindrical thing with two modes, despite the tender being a basic slatted floor model.
With the valve set to "low" it's still quite easy to pump as you approach the target pressure.
Set to "high" (for inflatable floors) and you'd be searching for vital organs in nearby shrubbery.

I'd agree that it's difficult to over pressurise with a concertina type foot pump.

.

 

[Sheppy]

Another important point to note is ambient temperature and direct sunlight. If you pump your tender up hard in the morning, then leave it on your mooring or boat all day in the hot sun, it may well burst as the heat can increase the pressure quite considerably. So you'll have to make adjustments on the fly and maybe let some air out again when you get to your mooring. Some values have a pressure release component but I think these are found more on larger RIB's than tenders.

 

[capsco]

I have just aquireda second hand lodestar Rib it recommends 0.25 bar or 3.6psi it also has a safety relief valve
Not really relevant to OP question but I am pleasantly surprised by this little Rib.

 

[Davegriff]

Pump up 'til you think its hard enough. Put on water a get aboard. If it bends in the middle it's not hard enough so add air. Simple. To get the thing back in it's bag, you'll probably need to deflate it fully then use the pump in reverse to suck the last of the air out.

 

[landlockedpirate]

Pump up 'til you think its hard enough. Put on water a get aboard. If it bends in the middle it's not hard enough so add air. Simple. To get the thing back in it's bag, you'll probably need to deflate it fully then use the pump in reverse to suck the last of the air out.

Ah, but it will bend in the middle even if you pumped it up to the right pressure in the first place. The moment you put it in the cold water the air pressure in the boat drops dramatically. Stick the boat in the water for about 5 mins, then top up as needed.

 

[wipe_out]

Took it out for a test run yesterday.. Pumped it to what I felt was quite hard but it probably could have been a little harder, or perhaps as mentioned the cold water cooled the air and reduced the pressure..

All went well although I think the little 3.5hp outboard might be over propped because is didn't feel like it was reaching full revs and any more than half throttle made no difference.. I see there are 3 props available for these small engines and the standard one is the 7" pitch which is also the highest pitch.. Maybe a 6" pitch would be better suited to the size of boat (2.6m)..

 

[landlockedpirate]

You have probably reached hull speed, slat floor hulls dont plane with standard power. I doubt that a change of prop will make a difference.

 

[[2068]]

slat floor hulls dont plane with standard power

3.5hp isn't enough oomph to plane unless you are built like a supermodel. You will be wasting your time messing around with props.
5hp on a slatted floor QuickSilver 240 Rollup = 9.9kts, as measured on the GPS , and I could charitably be described as "bear shaped".