Reply
 
Thread Tools Search this Thread
 
Old 29 March 2014, 11:22   #1
Member
 
Country: UK - Wales
Town: abergele
Boat name: all mine
Make: ribtec 3m
Length: 3m +
Engine: tohatsu 9.8 hp 2st
Join Date: Sep 2012
Posts: 275
first time out with new rig

I finally got out this morning, cloudy but nice and flat, I have a coupple of questions, I'm useing a 3.2m sunsport v airfloor along with 9.8hp tohatsu, I seem to be getting a lot of cavitation from the prop sounds like it's spinning and I also have a large air bubble towards the rear of the air floor any help would be great, I can get to 10mph before these two problems start
Thanks
__________________

__________________
slate1234 is offline   Reply With Quote
Old 29 March 2014, 13:47   #2
Member
 
Landlockedpirate's Avatar
 
Country: UK - England
Town: St Helens
Boat name: Wine Down
Make: Maxum
Length: 8m +
Engine: Inboard
Join Date: Apr 2012
Posts: 934
I would guess they are connected. Air floors, especially the V type need to be at exactly the correct pressure to stop them bending. The cavitation (Or more likely ventilation) is probably being caused by the less than smooth water flow under the hull.

Make sure you check the floor and tube pressure after its been in the water for 10-15 mins, then pump up as needed and it should sort out the problems.
__________________

__________________
Landlockedpirate is offline   Reply With Quote
Old 29 March 2014, 13:52   #3
Member
 
Country: UK - England
Town: Bath/Bristol
Make: Honwave 3.2
Length: 3m +
Engine: yamaha 20hp 1998
Join Date: Jan 2012
Posts: 30
In response to the bubble in the floor, I have found that it only happens on calm water as it builds up then starts to wave the floor gently even with the floor at top pressure. You might find in slightly chopped conidtions this might be less frequent due to the hull skipping across the rougher water and not building up the force on the hull. Thats my experience anyway with a 3.2 honwave 2007
__________________
Peter Dobie is offline   Reply With Quote
Old 29 March 2014, 14:32   #4
Member
 
Country: UK - Wales
Town: abergele
Boat name: all mine
Make: ribtec 3m
Length: 3m +
Engine: tohatsu 9.8 hp 2st
Join Date: Sep 2012
Posts: 275
Thank you for the replys, regarding the floor I didn't check the floor once on the water I think I was to excited just getting out lol, I took some fishing takle and that didn't even get damp lol, I think the cav plate was a bit high Click image for larger version

Name:	cav plate 1.JPG
Views:	216
Size:	192.3 KB
ID:	92807 as I got a lot of cavitation every time I turned, or opend the throttle so I have taken 25mm out of the transom useing a router along with some sikaflex it only took 20mins, I will try again in the morning weather permitting and let you know how it goes
__________________
slate1234 is offline   Reply With Quote
Old 30 March 2014, 08:15   #5
Member
 
Country: UK - Wales
Town: abergele
Boat name: all mine
Make: ribtec 3m
Length: 3m +
Engine: tohatsu 9.8 hp 2st
Join Date: Sep 2012
Posts: 275
I tried again today with the same results I am pumping the tubes to 0.25 anf floor to 0.35 useing this gaugeClick image for larger version

Name:	pressure gauge.JPG
Views:	249
Size:	180.9 KB
ID:	92827 I use the inner red part, is this correct ?? the boat gets on the plane easey with two of us in but the bulge in the floor is causeing a lot of ventilation/ cavitation (prop seems to be in and out of the water)
__________________
slate1234 is offline   Reply With Quote
Old 30 March 2014, 08:30   #6
Member
 
Country: UK - England
Town: Bath/Bristol
Make: Honwave 3.2
Length: 3m +
Engine: yamaha 20hp 1998
Join Date: Jan 2012
Posts: 30
On my honwave the pressures are 0.25 in tubes and 0.8 floor, so 0.35 seems very low to me, when I turn the boat over I can stand on the v without it collapsing and im 75 odd kilos! What does the manufacturer suggest pressure wise for yours or does it not mention any?
__________________
Peter Dobie is offline   Reply With Quote
Old 30 March 2014, 12:57   #7
Member
 
Country: UK - Wales
Town: abergele
Boat name: all mine
Make: ribtec 3m
Length: 3m +
Engine: tohatsu 9.8 hp 2st
Join Date: Sep 2012
Posts: 275
Thanks Peter sounds like I'm under pressure, I can't seem to find any info on a 3.2m sunsport,
__________________
slate1234 is offline   Reply With Quote
Old 30 March 2014, 13:05   #8
Member
 
Country: UK - England
Town: Bath/Bristol
Make: Honwave 3.2
Length: 3m +
Engine: yamaha 20hp 1998
Join Date: Jan 2012
Posts: 30
No problem, id say that yours is the same as honwave just different branding so get it to 0.8. If you hand or foot pump it, you can sure feel the pressure build towards the end so go steady if using a hand pump and go slow so you dont snap the pump shaft.
Good luck
__________________
Peter Dobie is offline   Reply With Quote
Old 01 April 2014, 04:48   #9
Member
 
Country: UK - England
Town: Southampton
Boat name: Ginger
Make: Avon SR4
Length: 4m +
Engine: 30hp yamaha
Join Date: Jun 2010
Posts: 207
Or get a bravo pump - dial in the pressure and off you go
__________________
rik_elliott is offline   Reply With Quote
Old 01 April 2014, 17:36   #10
Member
 
Locozodiac's Avatar
 
Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
Join Date: Sep 2007
Posts: 1,706
Slate, it that 9.8 a short or long shaft Tohatsu ?

Happy Boating
__________________

__________________
Locozodiac is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 18:54.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.