My Dinghy isn't hard enough!

But seriously, I stumbled upon a killer deal on an outboard motor for the roll up dinghy that came with my boat! And after one use I'm disappointed....

Past part throttle, the transom starts to fold in and the floor starts to cave in? Is this typical or is there something I can do to stiffen this boat up? It's a joke this thing is rated for 5 hp :lol:

No that’s not typical. Assuming it’s a decent quality boat, you don’t have enough pressure in it. It’s take a LOT of pumping to get an inflatable boat to the correct pressure. Once you do that, it will be very rigid.

Just keep the throttle back. Its not going to plane no matter how much air you put in the roll-up dinghy. So instead of 4.5 knots you only go 4.0. No big deal.

I agree with Guy, sounds like it needs more air. I want to use the phrase tight as a drum. There are pressure gauges available but you really shouldn’t need one. The boat I had with an inflatable floor needed the floor inflated to a much higher pressure than the tubes. The foot pump had two outlets, one low pressure for filling the tubes and one high pressure for topping off the floor.

If none of the above works, you could try putting one of those blue pills in each chamber. Might help.

Measure the surface area of the top surface of the pump in square inches.
150/4=37.5
If you weigh 150# and your pump has 37.5 sq in surface area, you will get 4 psi.
adjust the math for your weight and your surface area. The target for an inflatable dinghy is 4 psi. Floors may want more.
In my case, my inflatables always want more than I can give them, so I call upon a nearby heavy person to stand on the pump for the last few strokes.

bnoft said:

If none of the above works, you could try putting one of those blue pills in each chamber. Might help.

Click to expand...

After 4 hours you will need to see a doctor.

Ha! Nice!

I've kept the speed down and it helps. I'll pump some more air into it and see if that does anything. It sounds like I'm way under inflated.

Thanks!

West Marine used to sell some folding trim tabs that mounted to the transom and rode just under the stern tips of the pontoons. Made a bit of a flat surface there to help prevent the pontoons from digging down into the water. Worked surprisingly well at reasonable speeds.

But it made it a white-knuckle experience taking a 9' dinghy up on plane with an 8hp 2-stroke on it. Fast as Hell and felt like it would snap your ass out of there in a heartbeat if you didn't steer it EXACTLY right. You wore than kill-switch leash because you KNEW it would toss you out and come back to run you over!

It looks like they're no longer available? Shame, had I known I would have taken them off the old one when I got rid of it.
https://www.westmarine.com/buy/west-marine--trim-tabs-for-zodiac-inflatable-boat--7780182

99,
Just looks like more drag to me.
Forget all those rubbers and get a dinghy like this sized to your boat.

These: https://www.westmarine.com/search?Ntt=smart+tabs

They made an out of control Caribe 10 powered with a Yamaha 2 cycle 20 just rise up onto a plane with no fuss, no pointing the bow at the sky.

koliver said:

These: https://www.westmarine.com/search?Ntt=smart+tabs

They made an out of control Caribe 10 powered with a Yamaha 2 cycle 20 just rise up onto a plane with no fuss, no pointing the bow at the sky.

Click to expand...

The way to cure a boat that wants to point at the sky before it will go on plane is not a tiller extension, it’s adding some flat surface aft of the transom. The Smart Tabs do that very nicely.

My skiff would climb for the sky also until I installed tabs fixed flush with the bottom.

Can handle a 5hp outboard but I have a trolling motor on mine for now.

9.4 Sun dolphin/West marine Watertender ~ $500

Buy a Sevylor High pressure 12v. pump. Set the resssure (3.6 for my Quicksilver) and moments later it shuts off at the perfect inflation point. 10psi for the floor easily handled too. Inflates my Drop stitched, high pressure Sea Eagle Kayak in minutes too. Manual pumping is a chore...Especially if you have to hit 10 psi. Under $50 on Amazon. Great little pump..

https://www.amazon.com/Sevylor-15-PSI-Water-Sport-Pump/dp/B00HN93D8M/ref=sr_1_1?ie=UTF8&qid=1529767827&sr=8-1&keywords=sevylor+pump

Getting ready to order a Portland Pudgy though...I've had it with Blow-ups..

http://www.portlandpudgy.com/

I've had inflatable dinghies since the early 70's and have never had that problem with any of them unless they are underinflated. I keep mine nearly as hard as a basketball, which prevents any movement at the seams and actually makes it much more resistant to punctures, both of which add to longevity.
That said, I've never owned a cheap inflatable or a RIB. My last two have been the Zodiac Classic Mark I, the first of which lasted almost 10 years of hard daily use as our tender, with a 15hp 4 stroke engine. We are a year into our second one w/o any problems at all. As a charter boat, it is important to have a good dink, as it gets much harder use than a dink for a pleasure boat.
Try pumping it up a lot more.

I have an 8’ loves the 9.9 I put on it. Can be scary certainly overpowered.

HopCar said:

I agree with Guy, sounds like it needs more air. I want to use the phrase tight as a drum. There are pressure gauges available but you really shouldn’t need one. The boat I had with an inflatable floor needed the floor inflated to a much higher pressure than the tubes. The foot pump had two outlets, one low pressure for filling the tubes and one high pressure for topping off the floor.

Click to expand...

Is it possible that the dinghy was designed to have a hard floor or an inflatable floor?