Like Tree0Likes

lesson on twin stepp take off

Reply
Old 03-28-2009, 12:36 PM
  #31
No Comment
VIP Member
 
packinair's Avatar
 
Join Date: Jan 2002
Location: This post copyright, Packinair Inc. All rights reserved.
Posts: 1,637
Default

just stick 1000# of sand in the bow.. that should fix it
__________________
packinair is offline  
Reply With Quote
Old 03-28-2009, 12:43 PM
  #32
Registered User
 
Shanghied Again's Avatar
 
Join Date: Feb 2002
Location: Toms River NJ
My Boats: Shanghied! 2004 Donzi 33 ZX
Posts: 1,422
Default

Quote:
Originally Posted by boatnt View Post
sorry for the stupid question, but what are blow off vents?
On
Shanghied Again is offline  
Reply With Quote
Old 03-28-2009, 12:51 PM
  #33
Registered User
 
Shanghied Again's Avatar
 
Join Date: Feb 2002
Location: Toms River NJ
My Boats: Shanghied! 2004 Donzi 33 ZX
Posts: 1,422
Default

Quote:
Originally Posted by boatnt View Post
sorry for the stupid question, but what are blow off vents?
On a step bottom boat on the rear pad there would be two 1/2 or 3/4 brass thru hull openings that runs through your engine compartment out the transom or sides, They will have shut valves so if they leak you can shut them down. What happens on take off excess air gets trapped in the padded area and causes excessive prop slip and blow out. The Blow offs get the air thats trapped out from under the boat and reduce the slip from start.
you will see on the back of a lot of number 6 Drives these 2" black tubes coming off the back of the drive and they come up over the drive, this does the same it release the excess air from a step bottom boat and reduces prop slip. Helps the boat get on plane faster.
Thats why I asked what kind of boat and does she have a pad on the rear of the boat.
Shanghied Again is offline  
Reply With Quote
Old 03-28-2009, 01:48 PM
  #34
Registered
Thread Starter
Trade Score: (1)
 
Join Date: Jan 2005
Location: IL
Posts: 4,130
Default

Quote:
Originally Posted by packinair View Post
just stick 1000# of sand in the bow.. that should fix it
actually if you read the thread,I need to add the sand in the back so I could keep the stern in the water.

thanks for the reply
boatnt is online now  
Reply With Quote
Old 03-28-2009, 01:50 PM
  #35
Registered
Thread Starter
Trade Score: (1)
 
Join Date: Jan 2005
Location: IL
Posts: 4,130
Default

Quote:
Originally Posted by Shanghied Again View Post
On a step bottom boat on the rear pad there would be two 1/2 or 3/4 brass thru hull openings that runs through your engine compartment out the transom or sides, They will have shut valves so if they leak you can shut them down. What happens on take off excess air gets trapped in the padded area and causes excessive prop slip and blow out. The Blow offs get the air thats trapped out from under the boat and reduce the slip from start.
you will see on the back of a lot of number 6 Drives these 2" black tubes coming off the back of the drive and they come up over the drive, this does the same it release the excess air from a step bottom boat and reduces prop slip. Helps the boat get on plane faster.
Thats why I asked what kind of boat and does she have a pad on the rear of the boat.
thanks for taking the time to explain how blow off valves work!

the boat is a 2003 powerquest revenge with a small pad
boatnt is online now  
Reply With Quote
Old 03-28-2009, 02:03 PM
  #36
Charter Mod
Charter Member
 
BLee's Avatar
 
Join Date: May 2000
Location: E Dock
My Boats: Cigarette - "90MPH" Edition
Posts: 6,551
Default

Quote:
Originally Posted by boat teck View Post
this may be just another stubd queston and may not mean much hear with theas boats but has any dealer R&R the drives lately ? at the rear trim ram pin with the black caps covering the nut's there is a white plastic spacer in between the nut hard wear that could be installed wrong and it will change the drive trim angel a bit not leting the drive tuck in as far.they do this becouse there is a differents between bravo 1 & 3.and some guys will change that around by not knowing where to put it.on bravo 1 the spacers need to be installed with the grove part pointing a way from the bow of the boat or a way from the boat in general. well i'm shur it's fine but if not it a easy thing to look at any ways.it dose sound like the x is high but that is where the top speeds come in.you would think the manufacturer,s would by now say to you oweners to install lower unit drive spacers by now to help stop the blow out. merc dose sell them spacers also.just an idea is all this is.good luck and have fun this year boating.

I've had that exact thing happen after having a drive worked on with the Gun. It definitely can be overlooked, and made my boat cavitate like hell until it was swtched back.
BLee is offline  
Reply With Quote
Old 03-28-2009, 06:46 PM
  #37
Registered
Thread Starter
Trade Score: (1)
 
Join Date: Jan 2005
Location: IL
Posts: 4,130
Default

Quote:
Originally Posted by boat teck View Post
this may be just another stubd queston and may not mean much hear with theas boats but has any dealer R&R the drives lately ? at the rear trim ram pin with the black caps covering the nut's there is a white plastic spacer in between the nut hard wear that could be installed wrong and it will change the drive trim angel a bit not leting the drive tuck in as far.they do this becouse there is a differents between bravo 1 & 3.and some guys will change that around by not knowing where to put it.on bravo 1 the spacers need to be installed with the grove part pointing a way from the bow of the boat or a way from the boat in general. well i'm shur it's fine but if not it a easy thing to look at any ways.it dose sound like the x is high but that is where the top speeds come in.you would think the manufacturer,s would by now say to you oweners to install lower unit drive spacers by now to help stop the blow out. merc dose sell them spacers also.just an idea is all this is.good luck and have fun this year boating.
Well I just checked the trim limit blocks and they were on backwards,once I switched them the outdrives lowered about an inch,hopefully that will do it,I will let you guys know the results next time I go out.

Thanks for all the replys!
boatnt is online now  
Reply With Quote
Old 03-29-2009, 04:12 PM
  #38
Ginger or Mary Ann?
Charter Member
Trade Score: (1)
 
US1 Fountain's Avatar
 
Join Date: Oct 2000
Location: Lafayette. IN
Posts: 10,872
Default

A friend had a 34' PQ that also has the 2 large steps. His drives had spacers on it when he bought it. Possibly for this very reason?
__________________
Some people are like Slinkies - Not really good for anything, but they
bring a smile to your face when pushed down the stairs.
US1 Fountain is offline  
Reply With Quote
Old 03-29-2009, 05:36 PM
  #39
Registered
 
RollWithIt's Avatar
 
Join Date: Jun 2003
Location: Pittsburgh
My Boats: 98 Baja 36 Outlaw
Posts: 6,098
Default

So the two long vertical tubes I saw on the drives on the 42 Fountain at Cleveland were the blow off vents? They sat directly above the props and just looked like to tubes that went vertical and would stick out the water. The sales guy said they were to venitlate the props. But he made it sound like they provided air to the props so that the motors could get them rev'd up.
RollWithIt is offline  
Reply With Quote
Old 03-29-2009, 06:47 PM
  #40
Gold Member
Gold Member
 
omerta one's Avatar
 
Join Date: Apr 2006
Location: LOTO
My Boats: 2009 Lip-Ship Gladiator; 1995 Cig 20
Posts: 2,865
Default

[QUOTE=4mulafastech;2831045]The reason is if the drives are tucked 'too' far at speed in a hard turn, it is more likely to spin-out/roll a twin stepped hull due to the added stern lift. I never have my drives tucked all the way in when turning (rule #1 of driving a stepped hull). QUOTE]

The drives should not be trimmed below level when turning at speed...period.
omerta one is offline  
Reply With Quote
Reply

Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
KN
General Boating Discussion
31
08-25-2003 09:28 AM
Shane
General Boating Discussion
11
08-19-2003 08:55 AM
JO - PANTERABOATS
Pantera
4
10-18-2002 04:59 PM
rjcardinal
Donzi
19
03-16-2002 12:09 AM
Milord
General Boating Discussion
1
01-17-2002 09:25 AM



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 On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 03:15 PM.


Copyright 2011 OffShoreOnly. All rights reserved.