Go Back  Offshoreonly.com > General Discussion > General Boating Discussion
Low water pickup mounting height >

Low water pickup mounting height

Notices

Low water pickup mounting height

Old 12-06-2014, 04:34 PM
  #1  
VIP Member
VIP Member
Thread Starter
 
Cap'm Kurt's Avatar
 
Join Date: Apr 2009
Location: Lake Charles, La
Posts: 286
Received 30 Likes on 22 Posts
Default Low water pickup mounting height

DOES ANYONE HAVE EXPERIENCE WITH WHAT THE MINIMUM DEPTH YOU CAN GET AWAY WITH ON LOW WATER PICKUPS.

I have Latham Marine low water pickups mounted on the transom near the bottom of the V on a 30ft Sutphen with twin 502s. With the front edge flush with the bottom, the back is right at 1/2" deep and they are 2 1/4" wide. That's a lot of drag and probably a lot of pressure at 75mph. Previous owners have installed a 25psi water dump regulator and they start dumping right after planned off around 25mph.

Just to reduce drag I am going to grind the back edge off a little at a time until the 25psi regulators don't dump anymore. I have water pressure gauges connected after the water pump. Anyone played with this - that could add a mph or two. I have heard that some boats have them less than 1/8" deep and round the front edges to draw up the water better.

Also, what is adequate water pressure??? I would guess 10-15psi. Thanks.
Cap'm Kurt is offline  
Old 12-06-2014, 05:40 PM
  #2  
Registered
iTrader: (2)
 
Join Date: Aug 2005
Location: Between A Womans Leggs in IL
Posts: 6,321
Likes: 0
Received 1 Like on 1 Post
Default

i install them even with the bottom and away from the props so the picks dont air out the water so the props slip..18 psi is a good number..
FIXX is offline  
Old 12-07-2014, 09:32 AM
  #3  
Registered
 
Join Date: Jan 2012
Posts: 145
Likes: 0
Received 0 Likes on 0 Posts
Default

If you can put a small grove in the bottom of the boat in front of the pickup about 1/2 inch deep or so, and then start to grind and test. It will probably wind up close to leave with original bottom. An easy way to do this is put a temporary pressure gauge on the sea strainer can, and start from now when motors run cool, then make changes. 20psi is fine just remember volume cools engines not pressure, you need pressure to get the air out of the block. This is all assuming you are getting clean water.
43sv is offline  
Old 12-07-2014, 12:40 PM
  #4  
Platinum Member
Platinum Member
 
Join Date: Dec 2002
Location: Dallas, TX
Posts: 2,196
Likes: 0
Received 2 Likes on 2 Posts
Default

If your PU's are in clean water, it is doubtful you are going to want 1/2" below the bottom....that may end up being a lot of grinding. Every 1/8" in WPU length will likely show on the GPS. We switched from transom mounted PU's (1/8" below the bottom) to thru the bottom PU's. Best I remember, this was worth about + 2 MPH at 90+ MPH. Originally we used a trough in front of the thru-bottom PU's but ended up filling in the trough with the PU's totally flush with the bottom. Still get 10 lbs of WP mostly from vacuum. As long as you have positive WP, IMO the amount of pressure is not important. The goal is water flow not pressure.
BenPerfected is offline  
Old 12-07-2014, 04:53 PM
  #5  
Registered
iTrader: (1)
 
Join Date: Jun 2009
Location: Chicago
Posts: 8,215
Received 3,387 Likes on 980 Posts
Default

I was thinking of switching to these:

http://www.cpperformance.com/p-12543...ess-steel.aspx


Kinda tired of grinding away my current pickups to change the pressure.

Anyone have experience with them?
ICDEDPPL is offline  
Old 12-07-2014, 05:08 PM
  #6  
Registered
 
Join Date: Jan 2006
Location: taxachusetts
Posts: 2,963
Received 486 Likes on 264 Posts
Default

Originally Posted by ICDEDPPL View Post
I was thinking of switching to these:

http://www.cpperformance.com/p-12543...ess-steel.aspx


Kinda tired of grinding away my current pickups to change the pressure.

Anyone have experience with them?
they work great,,once you have it dialed in,,weld it,or "it" will fall off at some time.
sutphen 30 is offline  
Old 12-07-2014, 05:15 PM
  #7  
Platinum Member
Platinum Member
iTrader: (1)
 
14 apache's Avatar
 
Join Date: Apr 2005
Location: Northport N.Y.
Posts: 2,140
Received 10 Likes on 10 Posts
Default

Originally Posted by 43sv View Post
If you can put a small grove in the bottom of the boat in front of the pickup about 1/2 inch deep or so, and then start to grind and test. It will probably wind up close to leave with original bottom. An easy way to do this is put a temporary pressure gauge on the sea strainer can, and start from now when motors run cool, then make changes. 20psi is fine just remember volume cools engines not pressure, you need pressure to get the air out of the block. This is all assuming you are getting clean water.

You have experience?
14 apache is offline  
Old 12-07-2014, 05:23 PM
  #8  
Registered
iTrader: (5)
 
Join Date: Jul 2009
Location: Taunton Ma
Posts: 8,533
Received 693 Likes on 338 Posts
Default

I know a guy that tore one off...
Unlimited jd is offline  
Old 12-07-2014, 06:07 PM
  #9  
Registered
iTrader: (2)
 
Join Date: Aug 2011
Location: bel air, md
Posts: 2,735
Likes: 0
Received 3 Likes on 3 Posts
Default

Originally Posted by ICDEDPPL View Post
I was thinking of switching to these:

http://www.cpperformance.com/p-12543...ess-steel.aspx


Kinda tired of grinding away my current pickups to change the pressure.

Anyone have experience with them?
You still have to cut to fit. Had mine on and off the trail or 5 times to get it right.
Black Baja is offline  
Old 12-07-2014, 06:33 PM
  #10  
Platinum Member
Platinum Member
 
KWright's Avatar
 
Join Date: Mar 2011
Location: So. Burl. VT.
Posts: 938
Received 258 Likes on 107 Posts
Default

Originally Posted by 14 apache View Post
You have experience?
I'll bite, what part of his post is bs? That is the way Reggie did mine, and if you ever get to Key West, take a walk around the pits most all of the raceboats are done that way! Why all the hostility?
KWright is offline  

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.