hull jack settings

A general, non-powerplant specific, discussion on airboat technology, ie., hulls, rigging, polymer, etc..
Post Reply
sseater
Southern Airboat Member
Posts: 443
Joined: Fri Jan 21, 2011 11:33 am
Location: Altamonte Springs, FL

hull jack settings

Post by sseater »

so i ran my boat for the first time yesterday since i got it back together. its hopping really bad. i blindly set the jacks before going out all equally. i have 3 behind the tank and 3 in front of the tank. do i need to put more pressure on the front more than the back or the other way around? or all equal? i played with it while i was out there and just couldnt get it right... any advise is appreciated. i did a search on the subject and didnt find exactly what i was looking for.
Image

User avatar
Tony480
Site Supporter - I
Site Supporter - I
Posts: 5277
Joined: Sun Sep 10, 2006 5:52 pm
Location: lake county

Re: hull jack settings

Post by Tony480 »

You have 6 jacks??? Or 2 jacks that push down on 3 t bars each?

User avatar
farmboy
Site Supporter - VIII
Site Supporter - VIII
Posts: 2588
Joined: Sun Dec 11, 2011 3:20 pm
Location: Belle Glade . FL

Re: hull jack settings

Post by farmboy »

Tony480 wrote:You have 6 jacks??? Or 2 jacks that push down on 3 t bars each?
I was about to ask the same thing...
14ft JB Hull,Lycoming GSO480 w/water-meth injection,Sensenich 3-blade "R",ButtRaxx seats,B&S Trailer.

Member of Glades Airboat & Buggy Association / Kissimmee River Valley Sportsman Association

sseater
Southern Airboat Member
Posts: 443
Joined: Fri Jan 21, 2011 11:33 am
Location: Altamonte Springs, FL

Re: hull jack settings

Post by sseater »

yes 2 jacks, three t-bars each
Image

User avatar
aherr520
Site Supporter - III
Site Supporter - III
Posts: 1096
Joined: Thu Jun 26, 2008 9:42 pm
Location: Paisley

Re: hull jack settings

Post by aherr520 »

your going to have to play with the settings while your on the water, but you might need more then the jacks. If you have poly you can put some thin metal in between the hull and poly, should be an easy fix good luck with it
aaof member

User avatar
farmboy
Site Supporter - VIII
Site Supporter - VIII
Posts: 2588
Joined: Sun Dec 11, 2011 3:20 pm
Location: Belle Glade . FL

Re: hull jack settings

Post by farmboy »

sseater wrote:so i ran my boat for the first time yesterday since i got it back together. its hopping really bad. i blindly set the jacks before going out all equally. i have 3 behind the tank and 3 in front of the tank. do i need to put more pressure on the front more than the back or the other way around? or all equal? i played with it while i was out there and just couldnt get it right... any advise is appreciated. i did a search on the subject and didnt find exactly what i was looking for.
I've never had jacks help for hopping I've used jacks to help free the boat up on the ground & water now I'm not saying they will not help on hopping just never helped for me. I would set the boat on some flat hard ground adjust down until the hull will rock side to side very little. Be carful if you go to far it will wear your bottom out fast in the middle. Look on the back of your hull and see if it has a lip on it. If so take a "dead blow" hammer and hit it where the chimes start to bend upwards just where it barely touches the ground. Just keep making small adjustments and you will get it right. Mine was bad at first stuck to the water & ground and hopped... I putt 3 jacks in it set them where I wanted them worked on that lip in the back now it doesnt hop at all even with 40gallons of fuel and 3 people in the back seat and its free on the ground and water. I hope this helps and good luck! Kevin
14ft JB Hull,Lycoming GSO480 w/water-meth injection,Sensenich 3-blade "R",ButtRaxx seats,B&S Trailer.

Member of Glades Airboat & Buggy Association / Kissimmee River Valley Sportsman Association

User avatar
nebraskaairboater
Site Supporter - I
Site Supporter - I
Posts: 841
Joined: Thu May 06, 2004 12:42 pm
Location: Fremont, Nebraska

Re: hull jack settings

Post by nebraskaairboater »

If you have tension on the jacks take it out. In my experience on my boat as I added tension (pushed on the tbars) the nose came up. The more the nose came up the more it hopped. I would try that before getting too drastic. Start with no tension on the stringers and if it rides on the nose add tension until the just before it starts to hop. If it still hops check your engine angle with the stringers level. You want it level or a close with the stringers.
Dan Porter, Jr.
Fremont, NE
16 x 8 1971 Flat Bottom Fiberglass Hull / 454 Chevy/ 2.38:1 OX Drive / 80" 3-Blade Sensenich S

fishinfool64
Southern Airboat Member
Posts: 46
Joined: Sun Sep 11, 2011 10:51 am

Re: hull jack settings

Post by fishinfool64 »

set it on flat ground take a hammer and flatten that lip where your trim tab is mounted all the way across get it somewhat flat if you push off on the ground alot it bends it up
and will make it hop

torque
Southern Airboat Member
Posts: 77
Joined: Tue May 11, 2010 8:59 am
Location: Swamp fl.

Re: hull jack settings

Post by torque »

First of all, set your motor a little down in the back. that will bring the nosie up while running. The put it in deep water to set your jacks! The back jack should stay at neutarl an the front jack you should run it an start turning it down till you get it where you want it!! An if you jack the front one down an it starts hoping then tap your trim tab down or if you don't have one then back the front jack off a little at a time! jmo

User avatar
Waggs
Site Supporter - II
Site Supporter - II
Posts: 899
Joined: Mon Jul 21, 2008 5:50 pm
Location: Clermont, FL

Re: hull jack settings

Post by Waggs »

torque wrote:First of all, set your motor a little down in the back. that will bring the nosie up while running. The put it in deep water to set your jacks! The back jack should stay at neutarl an the front jack you should run it an start turning it down till you get it where you want it!! An if you jack the front one down an it starts hoping then tap your trim tab down or if you don't have one then back the front jack off a little at a time! jmo
If you're calling the prop end the back, then this advise is incorrect. Bring the prop side up to bring the bow up.
12.5' Predator, O320H2AD, 72" Whisper Tip Narrow

Liberty Mechanical Services
Performing all commercial and residential HVAC services
321-689-7709
Making America Cool Again!

KCCO

User avatar
Deano
Site Supporter - V
Site Supporter - V
Posts: 4571
Joined: Thu Jan 06, 2005 11:16 am
Location: Inverness, FL

Re: hull jack settings

Post by Deano »

Sseater, Waggs is correct. Evidently, Torque unintentionally mis-spoke.

Trimming the prop end of the engine is just like trimming an outboard.
Trim the motor up . . . the bow comes up.
Trim the motor down . . . bow comes down.
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
- Carl Sagan

Post Reply

Return to “Airboat Tech”