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Author Topic:   Lowering trailer bunks to the max.

Wet Foot posted 06-04-2004 12:32 AM ET (US)
Hi Guys,
How do you determine the maximum amount to lower trailer bunks and not drag your keel against the trailer cross-members?
The windshield and grab rail on the new 18 Dauntless I'm buying wont clear my garage's upper door jam. I need to lower the grab rail by 4.5 inches with the trailer unhitched from my vehicle, and the roller jack completely down (pushing it in by hand). I would rather lower the boat in the trailer as much as possible to preserve some rail and windshields height if I need to cut them down. The Shoreland'r trailer has 2 cross members but only the front is adjustable. The current clearance between the keel and front cross member is 4 inches. I would expect that if that distance was 1/2 inch, It might drag against it at certain ramps and water levels.
Is there a rule of thumb on this? I might be able to mount a smaller wheel to the tongue and not use the jack...maybe get another inch.
I'm also not sure about how much extra clearance I need. Any opinions here? So far my concrete driveway has not raised in the cold months. The boat comes with the windshield and rail unattached, so mounting it lower is no cost. I just hate to lose the height if there is a better option.

andygere posted 06-04-2004 03:02 AM ET (US)
If you lower the bunks as much as possible, you can always add a 12" V roller the the cross member, set just a bit higher the the cross member itself. That way, the boat will never drag across the cross member, it will roll instead. If this trick gets you close, you can always air the tires down a bit to get that last 1/2 inch or so. Keeping the fuel tank full when you park the boat will load the springs a bit, and you can always add some more ballast (wives, kids) too!
Moe posted 06-04-2004 09:07 AM ET (US)
If the boat sits down between the fenders, and the trailer has leaf springs, you may be able to gain some drop by switching to torsion axles. Dexter is the most widely used.
Make sure there's nothing hanging below the trailer frame at the stern, because this may cause it to drag going over speed bumps or dips.
--
Moe
Chuck Tribolet posted 06-04-2004 10:02 AM ET (US)
On my Shorland'r, the front of the bunks is adjustable,
but the rear attachment determines where you want it.
By changing the brackets at the rear you get it down an inch
or so. You want to move the bunk closer to the steel piece
that runs fore and aft. I'm considering doing this when I
change out the bunk boards someday, just to get the boat
a little closer to the water.
Lower the garage floor 6"?

Chuck

Wet Foot posted 06-04-2004 11:59 AM ET (US)
Thanks Everyone!
Moe, should the motor be above the frame for extra protection or is this unnecessary? Also, brackets bolted to my frame are below the frame. If my motor is tilted slightly above these, is that enough protection?
Chuck Tribolet posted 06-04-2004 02:20 PM ET (US)
Id worry more about hitting the motor at a change in
inclination, (like the Ryer's Island Ferry) than when
straddling a big rock. I'd get mine at the ferry if I didn't
tip the motor.
Chuck
Moe posted 06-04-2004 04:28 PM ET (US)
Since the motor lower end is behind the frame, I'd have it not only higher than the frame, but well above it, so it doesn't drag when coming out of, or into, a steep driveway.
Chuck's right about that change of inclination.
--
Moe

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Author	Topic: Lowering trailer bunks to the max.
Wet Foot	posted 06-04-2004 12:32 AM ET (US) Hi Guys, How do you determine the maximum amount to lower trailer bunks and not drag your keel against the trailer cross-members? The windshield and grab rail on the new 18 Dauntless I'm buying wont clear my garage's upper door jam. I need to lower the grab rail by 4.5 inches with the trailer unhitched from my vehicle, and the roller jack completely down (pushing it in by hand). I would rather lower the boat in the trailer as much as possible to preserve some rail and windshields height if I need to cut them down. The Shoreland'r trailer has 2 cross members but only the front is adjustable. The current clearance between the keel and front cross member is 4 inches. I would expect that if that distance was 1/2 inch, It might drag against it at certain ramps and water levels. Is there a rule of thumb on this? I might be able to mount a smaller wheel to the tongue and not use the jack...maybe get another inch. I'm also not sure about how much extra clearance I need. Any opinions here? So far my concrete driveway has not raised in the cold months. The boat comes with the windshield and rail unattached, so mounting it lower is no cost. I just hate to lose the height if there is a better option.
andygere	posted 06-04-2004 03:02 AM ET (US) If you lower the bunks as much as possible, you can always add a 12" V roller the the cross member, set just a bit higher the the cross member itself. That way, the boat will never drag across the cross member, it will roll instead. If this trick gets you close, you can always air the tires down a bit to get that last 1/2 inch or so. Keeping the fuel tank full when you park the boat will load the springs a bit, and you can always add some more ballast (wives, kids) too!
Moe	posted 06-04-2004 09:07 AM ET (US) If the boat sits down between the fenders, and the trailer has leaf springs, you may be able to gain some drop by switching to torsion axles. Dexter is the most widely used. Make sure there's nothing hanging below the trailer frame at the stern, because this may cause it to drag going over speed bumps or dips. -- Moe
Chuck Tribolet	posted 06-04-2004 10:02 AM ET (US) On my Shorland'r, the front of the bunks is adjustable, but the rear attachment determines where you want it. By changing the brackets at the rear you get it down an inch or so. You want to move the bunk closer to the steel piece that runs fore and aft. I'm considering doing this when I change out the bunk boards someday, just to get the boat a little closer to the water. Lower the garage floor 6"? Chuck
Wet Foot	posted 06-04-2004 11:59 AM ET (US) Thanks Everyone! Moe, should the motor be above the frame for extra protection or is this unnecessary? Also, brackets bolted to my frame are below the frame. If my motor is tilted slightly above these, is that enough protection?
Chuck Tribolet	posted 06-04-2004 02:20 PM ET (US) Id worry more about hitting the motor at a change in inclination, (like the Ryer's Island Ferry) than when straddling a big rock. I'd get mine at the ferry if I didn't tip the motor. Chuck
Moe	posted 06-04-2004 04:28 PM ET (US) Since the motor lower end is behind the frame, I'd have it not only higher than the frame, but well above it, so it doesn't drag when coming out of, or into, a steep driveway. Chuck's right about that change of inclination. -- Moe