Reply
 
Thread Tools Display Modes
 
Old 12-17-2013, 07:22 PM   #1
Guru
 
N4712's Avatar
 
City: South FL
Country: U.S.A
Vessel Name: Oliver
Vessel Model: Nordhavn 47 Hull# 12
Join Date: Apr 2013
Posts: 3,613
We just got all the hoses replaced on our davit, and were going keep the olds for spares. Anyways if a hose was to break, is there a safety feature to prevent it from plummeting down and screwing a lot of stuff up? Our model is a 1300lb Aritex Davit with 10ft telescoping boom.
__________________
Advertisement

__________________
Thanks, Oliver
M/V Oliver
Nordhavn 47 Hull #12
N4712 is offline   Reply With Quote
Old 12-17-2013, 10:06 PM   #2
Guru
 
Forkliftt's Avatar
 
City: Biloxi Mississippi
Country: USA
Vessel Name: Patricia Louise II
Vessel Model: 1983 42' Present Sundeck
Join Date: Oct 2007
Posts: 2,433
I'm not familiar with your specific system, but what you are asking about is called a "velocity fuse".
__________________

__________________
Steve Point Cadet/ Biloxi, Mississippi USA
*Present 42 twin 135 Lehmans
Forkliftt is offline   Reply With Quote
Old 12-17-2013, 10:34 PM   #3
Guru
 
N4712's Avatar
 
City: South FL
Country: U.S.A
Vessel Name: Oliver
Vessel Model: Nordhavn 47 Hull# 12
Join Date: Apr 2013
Posts: 3,613
Quote:
Originally Posted by Forkliftt View Post
I'm not familiar with your specific system, but what you are asking about is called a "velocity fuse".
Ahhh, I think we have those on it. I googled those and there're like round things that screw in to an block. we have a block on the bottom the cylinder for the boom, and can't tell if the swing and winch cylinder have one too, as there not visible.
__________________
Thanks, Oliver
M/V Oliver
Nordhavn 47 Hull #12
N4712 is offline   Reply With Quote
Old 12-18-2013, 04:06 PM   #4
Guru
 
River Cruiser's Avatar
 
City: UMR MM283
Country: US
Vessel Name: Northern Lights II
Vessel Model: Bayliner 3870
Join Date: Jan 2013
Posts: 1,226
On equipment like hydro cranes they use a load check valve. It will keep the boom from dropping if a line, hose or oring were to fail. If you have one it will be mounted on the cylinder, it restricts the flow of oil out of the cylinder without the control valve being shifted to send oil to the other side of the piston. May look like this:

Name:  image-4178133424.jpg
Views: 425
Size:  26.5 KB
__________________
Ron on Northern Lights II
I don't like making plans for the day because the word "premeditated" gets thrown around in the courtroom.
River Cruiser is offline   Reply With Quote
Old 12-18-2013, 05:43 PM   #5
Guru
 
Shoalwaters's Avatar
 
City: Rodney Bay Lagoon
Country: St. Lucia, West Indies
Vessel Name: "Dragon Lady"
Vessel Model: DeFever 41
Join Date: Feb 2008
Posts: 681
The little valves described will do the trick if you have an hydraulic failure. Most of the hydraulic davits I have seen move the hook up and down by a block and tackle working in reverse and driven by an hydraulic cylinder. Needless to say, the hook and its load will drop like a stone if the cable breaks, regardless of any fail-safes on the hydraulic side of things. Keeping the cable washed free of salt deposits will help it live a long and happy life. Unfortunately access to the block and tackle assembly can be well nigh impossible without dismantling the davit. A Bertram sportfish of my acquaintance had a new Marquip davit installed on the foredeck. I asked Marquip how to keep the davit healthy as that location gets liberally doused with sea water. Their answer was to put the boom all the way up, the cable all the way out, and squirt a water hose into the top of the boom. YMMV.
__________________
Mike
If all else fails, read the instructions
If it ain't broke, don't fix it
Shoalwaters is offline   Reply With Quote
Old 12-18-2013, 05:47 PM   #6
Guru
 
N4712's Avatar
 
City: South FL
Country: U.S.A
Vessel Name: Oliver
Vessel Model: Nordhavn 47 Hull# 12
Join Date: Apr 2013
Posts: 3,613
Quote:
Originally Posted by River Cruiser View Post
On equipment like hydro cranes they use a load check valve. It will keep the boom from dropping if a line, hose or oring were to fail. If you have one it will be mounted on the cylinder, it restricts the flow of oil out of the cylinder without the control valve being shifted to send oil to the other side of the piston. May look like this:
Yep, we got'em. They look like that except in SS.
__________________
Thanks, Oliver
M/V Oliver
Nordhavn 47 Hull #12
N4712 is offline   Reply With Quote
Old 12-18-2013, 05:50 PM   #7
Guru
 
N4712's Avatar
 
City: South FL
Country: U.S.A
Vessel Name: Oliver
Vessel Model: Nordhavn 47 Hull# 12
Join Date: Apr 2013
Posts: 3,613
Quote:
Originally Posted by Shoalwaters View Post
The little valves described will do the trick if you have an hydraulic failure. Most of the hydraulic davits I have seen move the hook up and down by a block and tackle working in reverse and driven by an hydraulic cylinder. Needless to say, the hook and its load will drop like a stone if the cable breaks, regardless of any fail-safes on the hydraulic side of things. Keeping the cable washed free of salt deposits will help it live a long and happy life. Unfortunately access to the block and tackle assembly can be well nigh impossible without dismantling the davit. A Bertram sportfish of my acquaintance had a new Marquip davit installed on the foredeck. I asked Marquip how to keep the davit healthy as that location gets liberally doused with sea water. Their answer was to put the boom all the way up, the cable all the way out, and squirt a water hose into the top of the boom. YMMV.
Thanks for the tip, Well do that. And ours is just as you mentioned with the hydro cylinder with block.
__________________
Thanks, Oliver
M/V Oliver
Nordhavn 47 Hull #12
N4712 is offline   Reply With Quote
Old 12-19-2013, 09:26 PM   #8
Guru
 
N4712's Avatar
 
City: South FL
Country: U.S.A
Vessel Name: Oliver
Vessel Model: Nordhavn 47 Hull# 12
Join Date: Apr 2013
Posts: 3,613
Here's a pic I got today, pretty sure that's it.
Attached Thumbnails
Click image for larger version

Name:	image-709542464.jpg
Views:	89
Size:	46.3 KB
ID:	25927   Click image for larger version

Name:	image-507612136.jpg
Views:	86
Size:	45.4 KB
ID:	25928  
__________________
Thanks, Oliver
M/V Oliver
Nordhavn 47 Hull #12
N4712 is offline   Reply With Quote
Old 12-19-2013, 11:10 PM   #9
Guru
 
River Cruiser's Avatar
 
City: UMR MM283
Country: US
Vessel Name: Northern Lights II
Vessel Model: Bayliner 3870
Join Date: Jan 2013
Posts: 1,226
Quote:
Originally Posted by N4712 View Post
Here's a pic I got today, pretty sure that's it.
looks like one to me.
__________________
Ron on Northern Lights II
I don't like making plans for the day because the word "premeditated" gets thrown around in the courtroom.
River Cruiser is offline   Reply With Quote
Old 12-20-2013, 08:40 AM   #10
Guru
 
N4712's Avatar
 
City: South FL
Country: U.S.A
Vessel Name: Oliver
Vessel Model: Nordhavn 47 Hull# 12
Join Date: Apr 2013
Posts: 3,613
Quote:
Originally Posted by River Cruiser View Post
looks like one to me.
Ok, I thought so.
__________________

__________________
Thanks, Oliver
M/V Oliver
Nordhavn 47 Hull #12
N4712 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

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





All times are GMT -5. The time now is 02:56 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012