Fishnhunt New Zealands main hunting and Fishing Forum. millions of posts on fishing and hunting, dogs, 4x4 vehicles, outdoors and much more Welcome, Guest. Please Login or Register
Page Index Toggle Pages: 1 Send TopicPrint
Normal Topic Cavitating. (Read 1210 times)
bufferzone
Donor Member
*****
Offline


I Love The FishNhunt Forum

Posts: 501
Location: top of the south
Joined: Sep 9th, 2014
Gender: Male
Cavitating.
Jun 4th, 2017 at 8:02am
Print Post  
I have a 3m aqua marine inflatable with a 15hp 2 stoker , inflatable floor joby. Having trouble with it cavitating.  Wondering why and how too combat this, I'm thinking its because the floor can flex instead of being hard? I've bin using it for hunting trout, its bin a really good steady platform as I can stand up on the seats and spot for cruisers. I'm an addicted fly fisherman, ....there I said it
  
Back to top
 
IP Logged
 
Rugersst
Forum Font
*****
Offline


Victory is mine...

Posts: 1368
Location: Pilbara WA
Joined: Nov 8th, 2010
Gender: Male
Re: Cavitating.
Reply #1 - Jun 4th, 2017 at 2:51pm
Print Post  
Larger propeller maybe...

Just fitted a hydrofoil to my boat to hold the nose down and it has caused the same issue  Undecided  I have a larger prop to try when I get round to it.
  
Back to top
 
IP Logged
 
INOV8A
Full Member
***
Offline


I do my own stunts!

Posts: 348
Location: Auckland
Joined: Jul 21st, 2008
Gender: Male
Re: Cavitating.
Reply #2 - Jun 5th, 2017 at 8:28am
Print Post  
I would say definitly a floor issue.
We used to run the Arancia inflatables for extreme Landbased fishing and they have an inflatable keel with a hard floor that slides in. There was a model that had a hinge in the middle of the floor which is how you get it in and out. The lifeguards ended up calling this an ankle breaker because it would flex at the join when they hit waves and break ankles!
So they moved the hinge forward.
When the floor is not rigid the flex can happen and allow air to form under the hill and disrupt the flow over the prop causing cavitation.
So your choices are to go with something with a rigid floor or make sure all your tubes are always solid with air and try to reinforce the floor to provide more rigidity.
We also found that too much weight in the nose can cause it, so try evening up your weight distribution favouring the back.
  
Back to top
IP Logged
 
QUACKERS
Forum Font
*****
Offline


DUCK FEVER NEVER DIES.

Posts: 1580
Location: The Pa
Joined: May 13th, 2008
Gender: Male
Re: Cavitating.
Reply #3 - Jun 6th, 2017 at 5:56pm
Print Post  
can you drop the motor down a click or two, mine was doing this on my tinny so i dropped it down two positions and all good.
  
Back to top
 
IP Logged
 
Cigar
Just Joined
*
Offline


New Zealand's Hunting
and Fishing Forum

Posts: 43
Location: Hamilton
Joined: Apr 16th, 2017
Gender: Male
Re: Cavitating.
Reply #4 - Jun 6th, 2017 at 8:07pm
Print Post  
QUACKERS wrote on Jun 6th, 2017 at 5:56pm:
can you drop the motor down a click or two, mine was doing this on my tinny so i dropped it down two positions and all good.

Yes, it could be ventilation rather than cavitation (though they are similar). Assuming they are trimmed correctly, the motors may be too high. In Rugersst's case, it may have been fine before the hydrofoil was added, but now having the boat more bow down also means the stern is sitting higher than it was.
  
Back to top
 
IP Logged
 
Rugersst
Forum Font
*****
Offline


Victory is mine...

Posts: 1368
Location: Pilbara WA
Joined: Nov 8th, 2010
Gender: Male
Re: Cavitating.
Reply #5 - Jun 6th, 2017 at 8:35pm
Print Post  
Cigar wrote on Jun 6th, 2017 at 8:07pm:
Assuming they are trimmed correctly, the motors may be too high. In Rugersst's case, it may have been fine before the hydrofoil was added, but now having the boat more bow down also means the stern is sitting higher than it was.



Cheers for that info its been pissing me off since I last had it in the water, just went outside and had a looky at the angle of the motor in relevance to the bow and its definitely out as it sits on the trailer.
I spent the minute it took and dropped the trim by one hole so shall see how it goes next outing, here hoping   Cool
  
Back to top
 
IP Logged
 
bufferzone
Donor Member
*****
Offline


I Love The FishNhunt Forum

Posts: 501
Location: top of the south
Joined: Sep 9th, 2014
Gender: Male
Re: Cavitating.
Reply #6 - Jun 7th, 2017 at 12:48pm
Print Post  
Yeah thanx for the info, will have a look at adjusting
  
Back to top
 
IP Logged
 
Page Index Toggle Pages: 1
Send TopicPrint
 

FishnHunt - New Zealands Famous Hunting and Fishing Forum Since 1995 » Powered by YaBB 2.6.11!
YaBB Forum Software © 2000-2017. All Rights Reserved.
Site Design By Alan Simmons - PRism and all rights are reserved from 1995 and onwards