How to get an Inflatable up to speed

[jfkal]

I have a 3 person ZODIAC with a 6 HP Suzuki four stroke. Cant seem to get it on a plane though. Any tricks on what to improve (except my own weight which is a constant ;-).

I am getting 4 kn at half throttle and also 4 kn at full throttle (RPM only change marginally then). Any idea, link etc welcome.

Thx

 

[Malcb]

Check position of the horizontal pin that dictates the trim of the engine on the transom. If the engine is slightly 'tilted' away from the bottom of the transom, in other words, if the pin is in the hole farthest away from the transom, then the engine will tend to push the bows up and the stern down and thus stop the inflateable getting on the plane.

The engine handbook should give a guide as to how to adjust the trim of the engine.

I can get my flat bottomed Plastimo 2.4m on the plane with a 4hp 2 stroke. with no trouble. It's a bit like driving a tea tray though /forums/images/graemlins/grin.gif

 

[vyv_cox]

Move your weight forwards when trying to get on the plane. You can buy extension tillers for some outboards so that you can still control the engine when sitting on the thwart. Or you can just lash a stick to the tiller. When single-handed, you will find that once planing, subtle shifts of your body are sufficient to steer the dinghy, although you need to leap sternwards to shut down the power.

 

[saltwater_gypsy]

Is it flat bottomed or an inflatble rib. My inflatable Zodiac RIB (2.4m) goes like the clappers with 6HP(Johnson 2-stroke).
Is sir perhaps a trifle on the heavy side????
OR the motor may be under performing.

 

[seumask]

I can get my flubber up on the plane (one adult 12 stone one 5 year old) with the Mariner 3.3, however I have to be sat on the seat and young son in the bow. To control from there I use one half of an oars which fits over the steering and the other to knock the throttle up and down. Echo the teatray experience, all quite exciting really untill the prop cavitates and wont let you go all that fast.

 

[Channel Ribs]

You should really be getting more than 4kn out of a sub 3m inflatable and a 6HP motor, I would check the engine first and foremost.

Does all this talk of exciting tea tray experiences mean I should stop my research into dagger boards for small inflatable tenders?

 

[jwilson]

Sounds like a very sick engine.....

 

[No Regrets]

My Honwave 2.7 Airdeck and 5hp Honda four stroke flatly refused to plane....

I figured a 2 or 3hp engine would be just as good. /forums/images/graemlins/frown.gif

 

[tjbrace]

I have a Quicksilver 3.4 Airdeck (5 persons rating) with Honda 6. Planes well with just me + luggage. Honda has had the usual mod to get more ooompff.

 

[jeremyshaw]

The only other thing which I think hasn't been mentioned is: have you got it pumped up tight? Maximising the pressure will increase the buoyancy - I notice the difference on my hard-floored rib. If you are worried about over-inflating you can get check valves - often supplied with the boat.

 

[affinite]

I assume you have the std prop on your Suzuki. I had an 4hp evinrude once that was originally meant to power a small yacht - prop pitch was all wrong for tender use and wouldnt get my 2.4m tender planning at all.

BTW - Honwave + Honda O.B. = Heavy engine on a heavy boat ?? (Nice rig though)

 

[jfkal]

Thanks Guys for all the advise. Will try next weekend. Engine is brand new but a 4 Stroke ............... .

 

[jfkal]

Its a flat bottom with a air bladder under the floor boards supposed to help to get it on a plane. SIR weight 80 kgs hence the weight ist not a variable factor and for sure not the problem....... . .