First Voyage!... a little slooow.. :-(

ferryden · 05 June 2011, 18:35

Bought an old model 15hp Mariner 2 stroke and fitted to a Quicksilver 340 Airdeck.

Had the engine serviced at a local marina (...couple of hundred quid!). They told me the cylinder power was ok and I therefore expected the boat to get on the plane pretty easily with me and my 15 year old lad in it.

It didn't!... so instead of now thinking of pulling my lad in a ringo...I'm frustrated and shitting myself at the thought of having to save for a bigger engine...

Only thoughts were that maybe I hadn't got the engine trim right..or maybe could have squeezed a few more cubic cm of air into the tubes... could they make a real difference or is it all about base outboard power?

Any tips for how to get the bugger on the plane guys?

.. maybe chuck my son off ? LOL!

Thanks once again for all your valuable advice, which I have valued so far as I stumble into Sibbing!

xxx
Ferryden

TIMO · 05 June 2011, 18:38

Quote:

Originally Posted by ferryden

Bought an old model 15hp Mariner 2 stroke and fitted to a Quicksilver 340 Airdeck.

Had the engine serviced at a local marina (...couple of hundred quid!). They told me the cylinder power was ok and I therefore expected the boat to get on the plane pretty easily with me and my 15 year old lad in it.

It didn't!... so instead of now thinking of pulling my lad in a ringo...I'm frustrated and shitting myself at the thought of having to save for a bigger engine...

Only thoughts were that maybe I hadn't got the engine trim right..or maybe could have squeezed a few more cubic cm of air into the tubes... could they make a real difference or is it all about base outboard power?

Any tips for how to get the bugger on the plane guys?

.. maybe chuck my son off ? LOL!

Thanks once again for all your valuable advice, which I have valued so far as I stumble into Sibbing!

xxx
Ferryden

It Sounds like trim to me mate.

lockieboi · 05 June 2011, 18:50

Something definantly isnt right.

My 3.2 airdeck got on plane easy with a 9.9 2 stroke even with 3 of us in it!!

Are the tubes and floor pumped up correctly? On my first trip mine sort of buckled in the middle because the tubes wernt pumped up hard enough.

With regard to trim ive never adjusted it, just left it how i got it really which is in the most straight position if that makes sense.

Also may be worth shuffling the weight about abit, try and get in the middle of the boat.

Good luck mate.

willk · 05 June 2011, 18:54

There should be no problem getting on the plane.

As stated by Timo - probably trim position - experiment, but higher until the prop slips/ventilates while accelerating, then back down a notch.

Air pressure - Absolutely Critical, especially in the airdeck and keel.

Tiller extension - It's important to be able to shift the weight forward to get on the plane - you can move back a bit once you are up. You can make one up from white sink waste pipe to see if it helps. A telescopic unit is handy, if/when you buy one.

I can plane mine with a donegaldan, fuel and a bag of ground gear on board. You should have no probs so

Sinistre1 · 05 June 2011, 19:05

Have the same set up. Mercury Quicksilver 340 and Johnson 15hp two stroke. You should be getting on plane almost instantly. In all honesty even when the weight is not perfectly distributed, it is the difference between a split second and a second and a half. It just "pops" up on plane. Are you sure your prop is in proper nick? I had to switch mine due to a slightly spun hub that only gave way under full throttle. I now have a three blade Solas 9.25 X 10 and I love the combination of get up and go and top speed (21mph on Hummingbird 585c combo fish finder/gps). I still get 17 to 18 mph with two on board. I am using the bottom hole on trim (engine closest to transom) and engine sitting directly on transom (not raised at all). Minimal splashing and none comes over the splash guards while under way. Using a Bravo pump but honestly I think it is a bit inaccurate compared to the two way that came with the boat. I usually top off with the two way (for the floor). Hope you get it sorted out. It is a sweet combination. I often lust after the 380 Aerotec but from what I have been able to glean, we only give up performance on less than flat seas. Absolute speed difference (all other things matched) is less than 2 mph.

ferryden · 05 June 2011, 19:12

Can it really make that much of a difference?..

I thought the prop may have been tilted too much down in the water as the stern wave behind seemed pretty high...the bow didn't lift right up either though...?

ferryden · 05 June 2011, 19:16

Quote:

Originally Posted by Sinistre1

Have the same set up. Mercury Quicksilver 340 and Johnson 15hp two stroke. You should be getting on plane almost instantly. In all honesty even when the weight is not perfectly distributed, it is the difference between a split second and a second and a half. It just "pops" up on plane. Are you sure your prop is in proper nick? I had to switch mine due to a slightly spun hub that only gave way under full throttle. I now have a three blade Solas 9.25 X 10 and I love the combination of get up and go and top speed (21mph on Hummingbird 585c combo fish finder/gps). I still get 17 to 18 mph with two on board. I am using the bottom hole on trim (engine closest to transom) and engine sitting directly on transom (not raised at all). Minimal splashing and none comes over the splash guards while under way. Using a Bravo pump but honestly I think it is a bit inaccurate compared to the two way that came with the boat. I usually top off with the two way (for the floor). Hope you get it sorted out. It is a sweet combination. I often lust after the 380 Aerotec but from what I have been able to glean, we only give up performance on less than flat seas. Absolute speed difference (all other things matched) is less than 2 mph.

Many thanks... this does suggest that the engine/prop power is letting me down...

willk · 05 June 2011, 19:18

Hard to say....

But if your motor was in the lowest position, your airdeck was a bit soft, you were sat at the back and yer son is a girt big lump, then yes, I think it could impede your progress somewhat

If the prop isn't knocked all to hell and the motor isn't over revving, then leave it until last - check the other stuff first, it's free.

ferryden · 05 June 2011, 19:56

OK Guys... thanks... I'll be trying EVERYTHING that's being suggested by you all...

I didn't know if I needed a mechanic or a psychiatrist to talk to...but this forum acts as both!

Cheers!

TIMO · 05 June 2011, 20:10

Quote:

Originally Posted by ferryden

OK Guys... thanks... I'll be trying EVERYTHING that's being suggested by you all...

I didn't know if I needed a mechanic or a psychiatrist to talk to...but this forum acts as both!

Cheers!

Mate ,, i seem to be in the same boat as you

i`m sure its all teething issues for us both,, just gotta stay with it and soak up the good advice

Peter_C · 05 June 2011, 21:47

Quote:

Originally Posted by ferryden

Can it really make that much of a difference?..

I thought the prop may have been tilted too much down in the water as the stern wave behind seemed pretty high...the bow didn't lift right up either though...?

Typically you trim down for takeoff. Meaning the prop is closer to the boat, and deeper in the water. This keeps the bow down, and helps push the boat out of the water. Trimming up raises the prop and is used when you want to fly the boat at higher speeds lifting the bow and allowing the boat to only contact the rear pad. Of course that would be for a boat with adjustable trim.

Try having your son sit in the bow to help get it on plane.

Proper air pressure could make a big difference. Make sure you can't fold the ends of the cones over or even better use a pressure gauge.

willk · 05 June 2011, 22:00

Quote:

Originally Posted by Peter_C

Proper air pressure could make a big difference. Make sure you can't fold the ends of the cones over or even better use a pressure gauge.

I'd forgotten to harp on about this - thanks Peter!

The QS airdeck will have pressures marked at each valve. These MUST be correct, or the boat will fail to act as it should. The airdeck will need something silly like 11psi in it. You can't judge this by hand and will require a gauge to do the job properly.

ferryden · 06 June 2011, 16:48

I only checked air pressure by hand - until the tubes showed decent firm resistance (... the double hand pump I used to finish off had a guage that didn't show a steady pressure reading). Once in the sea the tubes did feel softer than I expected..probably temperature?

How much difference would higher tube pressure make guys?.. (Hoping you say "a lot"!)
I think I'll try to find a pump with a guague to ensure I blow up to max...

I'll also play with the trim...

Fingers crossed!

lockieboi · 06 June 2011, 17:54

you would be better of with a seperate gauge in my opinion.

I think the ones that are on pumps arent that accurate. (i may be wrong!)

I have one of these but obviously your valves may be different.

INFLATABLE BOAT PRESSURE GAUGE, Europa Sport, ** NEW ** | eBay UK

willk · 06 June 2011, 18:37

Quote:

Originally Posted by ferryden

How much difference would higher tube pressure make guys?.. (Hoping you say "a lot"!)

A lot. Are you using a pump like this to finish the floor and keel? It must be the cheapest one about and if you have the Quicksilver clip-in valves, will show a constant pressure when you pause pumping. The airdeck should be like a plank when it's done,

actions · 06 June 2011, 19:09

My old SIB was a 3.2 with an 8hp on the back and this planed very easily with two adults in, 1, 10st and the other 15st, plus fuel, kit etc etc.

3 adults and we started to struggle

, so with a 15 you should be flying

My air deck as has been said was like a "plank", to the point when i thought it couldnt take any more, but when i put the pressure gauge in it still needed a bit more puff.

I would certainly get the tuubes up to their recommended pressure, but you wont know what level your at until you get a gauge.

good luck.

Sinistre1 · 08 June 2011, 09:18

Feryden, How are you getting along? I have to agree about the pressure comments. If you are woefully underpressure, it WILL affect the boat alot. If you are in the right ballpark though, t should be much less noticeable. The hard as a plank school of thought definitely applies for the floor. Using the two way pump that comes with the boat, i can tell you that you will be pumping almost to the point where it seems pointless (seems no air is going into the floor), at THIS point if you pause between strokes you should find the pressure is just right. 11 PSI is a lot more than you think in this situation. To convince myself, in the early days of my sibbing career, I inflated just the airdeck on the living room floor and walked on it. At pretty much anything under the correct pressure lots of deflection. It doesn't really start to behave like a stiff board until anything after 9 PSI. I also tend to fill my tubes to 3.5 to start and then check again after wetting them (this usually works out for me). Last silly thought but I don't recall anyone asking, what length is your motor leg (and you thought I would say shaft, didn't you). I only ask because very infrequently someone is found to be using a motor off their old sailboat or such and it has a very long shaft. This would absolutely KILL performance with all the extra drag. You must use a short shaft for that boat. Some folks even raise the motor a bit but I found that makes mine cavitate something awful. Just a thought.

ferryden · 09 June 2011, 19:04

Thanks for asking bud - I'm sure that I can improve my trim as had my prop set right under into the transom - but I also think I need a different pump and am looking at alternatives... I think I was too nervous of blowing the tubes up too hard on first voyage so know I can 'pump it up'!
Unfortunately I'm gonna be travelling around with work over the next few weeks despite being champing at the bit to go and see what difference these adjustments might make..
But the Doubting Thomas side of me still says the engine should still be firing this boat forward under semi pressure, rather than chugging along...
Hmmmnnn

Thanks again for asking ... the people on this forum are brilliant!..Thanks to you all!
:-)

ferryden · 09 June 2011, 19:10

Quote:

Originally Posted by willk

A lot. Are you using a pump like this to finish the floor and keel? It must be the cheapest one about and if you have the Quicksilver clip-in valves, will show a constant pressure when you pause pumping. The airdeck should be like a plank when it's done,

Thanks mate...mine looks identical, but not Quicksilver logo. As the needle was firing around as I pumped I didn't trust the guage...think I need to pause and wait on a stable reading.... To be honest the airdeck rose in the middle a bit when I inflated the keel, so maybe the deck wasn't hard enough on that basis..

The keel inflated quickly and I was nervous it was going to burst as it went up so fast... I need to Get Some Nuts!! and pump her a bit harder ...

willk · 09 June 2011, 20:32

Quote:

Originally Posted by ferryden

The keel inflated quickly and I was nervous it was going to burst as it went up so fast... I need to Get Some Nuts!! and pump her a bit harder ...

That's because it has a small volume. Do watch it, it would be easy to overfill it.