It is currently 21 Jul 2018, 16:48
Join the free forum or login with your account and the annoying banner goes away

Wired2fish

All times are UTC - 5 hours [ DST ]




 Page 1 of 1 [ 11 posts ] 
Author Message
PostPosted: 28 Jul 2016, 13:56 

Joined: 24 May 2016, 11:22
Posts: 8
Location: third coast
I am working on an older polarkraft 14' flat bottom. The question I have is where should the cav. plate be? Even with the bottom of the boat or above due to the tunnel? When I purchased the boat it had a redneck engineered lift for the motor(40hp nissan)that puts the cav plate about 2-3 inches above bottom of boat. the only reason asking I cannot seem to get the motor to get to full power. It does super on muffs but when getting on the water it seems to bog out about 3/4 throttle. Wondering if cavitation is causing this. Thanks for any input.. Mike from Gtown


Offline
 Profile  
 
PostPosted: 28 Jul 2016, 16:51 
User avatar

Joined: 05 Feb 2016, 03:42
Posts: 399
Location: Langley, BC
Level with bottom of boat. The tunnel is for a jet foot to sit in.


Offline
 Profile  
 
PostPosted: 28 Jul 2016, 17:05 
User avatar

Joined: 20 Aug 2010, 14:46
Posts: 1700
Location: Halifax, Virginia
Cavatation makes the motor turn more RPMs since there is less resistance on the prop or impeller for jet. Are your running a prop or jet? Assuming prop since jet doesn't have a cavatation plate.



_________________
Jonah
www.RiverBottomOutdoors.com

Facebook
https://www.facebook.com/RiverBottomOutdoors

My Boats:
1656 CCJ http://www.tinboats.net/forum/viewtopic.php?f=21&t=29361
1448 MV http://www.tinboats.net/forum/viewtopic.php?f=21&t=15412

Image
Offline
 Profile WWW  
 
PostPosted: 28 Jul 2016, 17:26 

Joined: 24 May 2016, 11:22
Posts: 8
Location: third coast
Thanks guys, I guess I have some mods to the motor lift to do.


Offline
 Profile  
 
PostPosted: 28 Jul 2016, 17:53 
User avatar

Joined: 17 Apr 2014, 15:39
Posts: 490
Location: Cullman, Alabama
stinkfoot wrote:
Level with bottom of boat. The tunnel is for a jet foot to sit in.


They do make different style tunnels, one for a jet foot and one for a prop. So I would think you would want it level with the top of the tunnel since it is there for the purpose of raising your motor.



_________________
2016 Alumacraft 1648 NCS - 1992 Johnson 9.9 HP Tiller
http://www.tinboats.net/forum/viewtopic.php?f=21&t=40764
Offline
 Profile  
 
PostPosted: 28 Jul 2016, 23:30 
User avatar

Joined: 13 Oct 2011, 23:54
Posts: 209
Location: Tennessee
stinkfoot wrote:
Level with bottom of boat. The tunnel is for a jet foot to sit in.

Depends on the tunnel. There are tunnels for jets and for props.



_________________
On a shallow river in a RiverPro!
Offline
 Profile  
 
PostPosted: 29 Jul 2016, 00:02 

Joined: 25 Sep 2014, 14:19
Posts: 37
Check your prop pitch. May be more than your motor can turn. Set your cavitation plate even with the top of the tunnel. Get ready to play around with it a lot. You may want to invest in a manual jack plate. With a 40 you should be able to turn a prop with enough cup in it to jack that motor even higher with a little setback.


Offline
 Profile  
 
PostPosted: 29 Jul 2016, 14:48 
User avatar

Joined: 27 Nov 2010, 09:36
Posts: 4446
Location: Houston, TX & Crossville, TN
From an older G3 adv.

richg99

http://boats.iboats.com/research/2010-g ... 82011.html

Image



_________________
“That which is measured improves. That which is measured and reported... improves exponentially.

Karl Pearson"
Offline
 Profile  
 
PostPosted: 29 Jul 2016, 21:37 
User avatar

Joined: 05 Feb 2016, 03:42
Posts: 399
Location: Langley, BC
wmk0002 wrote:
stinkfoot wrote:
Level with bottom of boat. The tunnel is for a jet foot to sit in.


They do make different style tunnels, one for a jet foot and one for a prop. So I would think you would want it level with the top of the tunnel since it is there for the purpose of raising your motor.

I understand that but if he is cavitating then he likely doesn't have the latter. I would put the cav plate level with the bottom and see what happens. You can always crank it up incrementally afterwards.


Offline
 Profile  
 
PostPosted: 30 Jul 2016, 02:11 

Joined: 25 Sep 2014, 14:19
Posts: 37
If its bogging he wont be cavitating. Running a tunnel with the cavitation plate even with the bottom of the boat can cause excessive spray off the foot. Tunnel design has a lot to do with it but you should run it even with the top of the tunnel and then adjust the prop to counter any cavitation.


Offline
 Profile  
 
PostPosted: 01 Aug 2016, 17:48 

Joined: 24 May 2016, 11:22
Posts: 8
Location: third coast
thanks you all I have been out of town. I have been trying to figure this out I am going to try and get some pics. posted of the tunnel and how the motor is sitting currently, as it is it's not even with either the top of tunnel or bottom of boat. I do plan on getting a manual jack plate but I cannot do that for a while yet. Family has to go first. It does make sense to have it even with the tunnel and I do think it may be too low because it does have a bit of spray up sideways from the foot when it is getting up to the speed it will reach before bogging down. Thanks again for all of your input. This is my first tin boat but now have two. Kind of addicting especially when you get crazy good deals on them and willing to put in the elbow grease.


Offline
 Profile  
 
Display posts from previous:  Sort by  
 Page 1 of 1 [ 11 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: Google Adsense [Bot] and 70 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Join the free forum or login with your account and the annoying banner goes away

eaglelodgemaine