keel height from pavement on trailer?

KurtG

Petty Officer 1st Class
Joined
Apr 27, 2007
Messages
323
After taking a casual run down to the community launch (7 blocks away) and seeing mud out past the end of the ramp, I'm still squezing every inch out on my trailer. Not that it would have done any good this day.

The ramp is my major impediment to getting on the water. I have a keel roller and short bunk trailer with a tilt mechanism.

Over the winter, I added a 8' tongue extension that gets me about 6' or another 6" of water on that ramp in most situations.

Over the weekend we ran to the local trailer store and bought a couple of 8" wheels (900 lb load rating) to replace the 12" wheels (800 lb load rating) on the trailer. I noticed the 8" tires run about 16.5" and the 10 and 12" tires all run about 21". This extra clearance allowed me to modify the axel/spring setup and I reduced the clearance under the boat another 7".

With the new tires, the bottom of the boat at the rear of the trailer currently sits about 17.5" off the pavement where it was 24.5" with the 12" wheels. The axel is looking pretty low, but guess it is OK.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: keel height from pavement on trailer?

the main thing is clearance of the lower unit of the motor. transom saver.
 

marquette

Petty Officer 1st Class
Joined
Apr 18, 2006
Messages
372
Re: keel height from pavement on trailer?

i had a duck boat trailer one time that had 8 in wheels. i had no problems with it until they paved the boat launch and the water was low. when the wheels dropped of the end of the pavement the frame dropped right on to the concrete. i changed to 12 in wheels and the problem was solved. so i would be careful the first time to the launch now that you have lowered the trailer when you get to the end of the pavement. if it is an all dirt or gravel launch you should be ok.
 

bowman316

Lieutenant Commander
Joined
Oct 21, 2008
Messages
1,822
Re: keel height from pavement on trailer?

Why would you opt for smaller wheels?
I always thought the bigger the wheel the better.
 

Navy Jr.

Senior Chief Petty Officer
Joined
Sep 14, 2007
Messages
738
Re: keel height from pavement on trailer?

Why would you opt for smaller wheels?
I always thought the bigger the wheel the better.

Yes, you're right; big wheels are better for long hauls, but he's only 7 blocks from the ramp he frequents. He needs to get the boat closer (lower) to the water because that particular ramp is so shallow.
 

bowman316

Lieutenant Commander
Joined
Oct 21, 2008
Messages
1,822
Re: keel height from pavement on trailer?

ok, didn't think about that.
If you feel the keel is too low, try to adjust the keel roller in the front of the trailer, so that the front part of the keel will tile more upwards. Try to get more lift on the front of the keel.

I just put a keel roller on kinda below the bow roller, so it will get the keel away from the trailer frame.
 

KurtG

Petty Officer 1st Class
Joined
Apr 27, 2007
Messages
323
Re: keel height from pavement on trailer?

My question wasn't phrased well. What is the average height a boat sits on the trailer? How much water is required to launch?

My trailer at 24.5" was too high for our ramp; which is especially shallow. The set-up looked high in comparison to other boats.

I bought the smaller diameter wheels (16.5 versus 21.5") to reduce the height (2" height gain there), that 2" more under the fender allowed me to swap my axel/spring set up from under/over. So, the net gain with the smaller wheels is that I need 7" less water to launch the boat. Since the tides are in the 15" range, this might make a big difference in getting in the water. It now sits at 17.5" which seems normal, the only thing I don't like is that the axel mounts seem especially low- meaning no backing over the curb near our driveway.

I have the 12" wheels and can change back, but hope the reduced height gets me in the water more.
 

Wee Hooker

Chief Petty Officer
Joined
Sep 11, 2005
Messages
618
Re: keel height from pavement on trailer?

17" is certainly plenty. I think your on the right track ( having dealt with similar "lack of water"/lousy ramp) spots myself. Just be more carefull how you drive. You'll find out if you have an issue soon enough.
BTW: 7" is a significant gain! Congrats.
 

reelfishin

Captain
Joined
Mar 19, 2007
Messages
3,047
Re: keel height from pavement on trailer?

Your biggest concern with getting too low is having the outdrive or back of the trailer hit bottom when going in and out of driveways. If that's not an issue, and the boat is safely supported, then you should have no issues.
 

AZSenza

Chief Petty Officer
Joined
Mar 11, 2008
Messages
521
Re: keel height from pavement on trailer?

I've noticed a big difference in keel highths. Mine is pretty low with 13" tires. my boat will float right off the trailer when the front fender (tandem axel) is just under water, thats about 2 1/2' of water front 4' in the rear.
 
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