Hobie Cat Forums

The original configuration of my trailer is to have the crossbars mounted on top of the trailer frame. Looking it, it seems like a better option is to put those crossbars UNDER the frame. In my case it means that the boat will set 5" lower (2" crossbar and 3" frame). I've checked, and the wheels and fenders will clear.

The advantages are:
- 5" closer to the water when launching at a ramp (don't have to back down so far)
- 5" lower to get on top of the tramp when trying to raise the mast
- The mast will set 5" higher than the boat when on the mast support, which helps with leverage for a Mast Stepper.

The disadvantages are:
- harder to change a flat tire
- The rudders will smack into the ground if they accidentally fall

Am I missing anything? I'm about ready to make the change and am looking for any good reason not to.

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1989 Hobie 18 Magnum "Rhapsody"
2007 Hobie Tiger

You lose one of those U bolts and your boat's on the pavement.

With the crossbars the way they are, the U bolts are not in any serious stress. They just keep things together, since the trailer frame is taking all the vertical loads.

Reverse it and now the U bolts are taking all the vertical load and they have to keep things together. Are they up to it? Do you have good insurance?

I've seen it done both ways. In fact, I have three trailers and I know at least one is set up with the crossbars under the frame. The U-bolts are PLENTY strong to hold the boat. The U-bolts are probably good for well over 1000 lbs each but only see a couple 100 lbs at most. As long as they're not severely rusted they'll be fine.

Personally, I like having the boat a little higher away from the road surface, but your point about making it easier to climb up is a good one.

sm

I wouldn't be worried about the U bolts in a static condition.

It's the vibration and dynamic loading that would be their undoing.

It depends on how far you trailer. My trailers go on 1000+ mile trips several times a year, so I'm a little more sensitive to that stuff. I've got about 53,000 miles on my '04 Trailex double-stack and about 10,000 miles on my '72 Magline since I completely refurbed it in 2007.

If you decide to do that, ditch the nuts / lock washers that came with the U bolts and use nylock nuts instead. Split lock washers are worthless (there's a NASA fastener study that proved that back in the '70s).

I have a set of EPO's that are missing the bottom couple inches after they fell coming up the boat ramp and I didn't spot it until parked a couple hundred feet later..


It might require moving the fenders.. but I have thought about moving the axle on my trailer.. Going from an axle under spring to axle over..


having the boat that much lower might save some fuel due to aero.. maybe..

But it would also put your boards as well as rudders at risk.. You would just have to change some habits I guess...


Oh and don't trust a lock nut.. Drill a hole in the bolt and put some safety wire/cotter pin in there if you do this.. Simple, cheap, and works awesome.

The trailer that we have that I know has the crossbars hung under the frame is at least 35 years old (an old galvanized highlander). I wouldn't even want to guess how many miles it's got on it, but it's a lot for sure and the crossbars have always been under the frame. No issues with the U-bolts (knock on wood). I'm fairly certain my Trailex also has the crossbars hung under the frame.

As far as having the rudders drag on the ground, well, there's not much you can do about that except make sure you tie them up properly. As long as you secure them well, there won't be any issues. If you drive up a ramp without bothering to tie them and they fall down, that's you're own fault and trailer crossbars over or under the frame, it's not something I'd ever let happen to my boat. Same goes with the daggerboards, just pull them out of the wells and throw them on the boat or in the car. Never drive around with them in the wells.

By the way, if the nuts & washers are going to vibrate free, its because they aren't torqued properly, not because the crossbars are over or under the frame. Make sure all the nuts on the U-bolts are tight (including all the other fasteners used on the trailer) and you'll be fine. Throw some loctite on them if you're worried. I'd choose red loctite and a lock washer over a nyloc nut any day of the week.

sm

after all the work you put into making your boat look as good as it does, why would you risk attracting all sorts of road grime to your hulls by lowering the boat closer to the road? the frontal area of the boat is nearly nil anyway so you are not gaining any aerodynamic advantage.

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Chris
'88 H18SE Arís

Grow a mullet, Notch the trailer frame, install airbags and skid plates, Air out and lay frame

Seriously I have considered adding bags to my trailer. I still may. Just to drop the trailer rear on the beach.

I have seen numerous cat trailers (esp. 14's and 16's) with the rear bars over and the front bars under. The explaination was to prevent the tramp from creating lift.

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Jeff
1986 Hobie 18 #13031
1977 Hobie 16 (As soon as I can get it out of a field...)

Hi,

My Hosclaw trailer was origonally configured w/ the trailer crossbars slung UNDER the trailer siderails .... and when I rebuilt/reconfigured it many years ago I moved the trailer crossbars to be ABOVE the .....

1) I agree w/ My Matt Bounds on this (about the U-Bolts ....).

2) I wanted to raise my boat up away from the road as much as possible ... I only take the boat on/off the trailer were hieght is an issue once (usually) at a event .... but I have trailered many many miles (est +100,000 miles trailered) .... so the risk of damage is much greater from "road hazzards".

3) We have to "jump" curbs, small ditches, and other obstructions all the time to get our trailers in a position so that we can unload them (boat) .... you "drag" the stern/tailend of the boat just once on a macadam/stone surface .... (and you will have some work that will occupy your evenings for you for awhile ... and you'll have to visit your "painter" friend again).

4) If you have only 8" dia tires and the crossbars under the trailer's siderails ... you maybe too low in fact to get the boat off the trailer and onto a set of "beach wheels" .... you may need to actually "drop/pull" the boat off the trailer first ... then lift the boat up to place it onto the beach wheels ....

5) I resist launching the boat directly from the trailer into the water .... since I sail 99% of the time in salt water .... it's bad for the trailer structure ... the lights .... the bearings (especially if warm/hot) ... etc.

6) Yes, I've had several friends who have dragged EPO Rudder Blades or Dagger Boards, down the highway ... in fact I have two EPO's (given to me) stashed up in the overhead in my garage in that condition .... since EPOV1's are only avialible used on E-Bay (sometimes) ... what does a "new" replacement EPO V2 now cost ... $400.00? ... so, I am very protective of my EPO's ...

.... so ...

A) I moved my trailer crossbars up on top of my siderails ....

B) Installed 12" dia tires on GALVANIZED rims .... less revolutions/tire when traveling down the highway ==> reduce tire wear and cooler bearings (I do not drive sloooow, just steady at a reasonable speed ... and "painted" rims rust after a few years and start leaking air along the bead)

C) Install "MUD FLAPS" on the fenders to prevent road debris/dirt from being "kicked" up onto the boat. Note: make sure the "mud flaps" extend inwards far enough to prevent "wheel bearing" grease from being slung up onto the hulls also ... (I have one axle seal that leaks alittle since the axle has a small groove worn it were the seal is .... especially on long hot road trips ... but I don't want to spend the $$$'s for a new axle ... yet ...)

D) I would move that nice, shiny, new(?) trailer "jack stand/wheel" back on your trailer tongue ( past 42" ...) because .... if you make a tight turn you can "pinch" it between the tow vechicle and the trailer in the folded/trailering storage position (don't ever leave it "down" when trailering ... if you bottom out you can "pop" the trailer off the hitch .... nasty things can happen then !!!) .... (don't even think of asking ...... after a +100,000 m you have "experience" ...)

You have done a EXCELLENT job so far .... be careful of going tooooo far ....

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

Oh ...

Those are really nice looking Magnum Seat Covers ..... who made them? (I will need a set in the near future ...)

I like the Magnum Seat Trailering Support .... NICE .... what diameter PVC Pipe did you use????

And .... I would "lose" those "side rollers' .... all they will do is mark up your BEAUTIFUL paint job .... just make sure you are careful to align the boat and trailer up when putting the boat onto the trailer ... the cradles both fore and aft will tend to keep the boat aligned w/ the trailer. I really like the cradles on both crossbars ... GOOD JOB ... (I have "bunks" since my trailer is used to haul several different model/size beach cats ... but I still don't have any issues ... if I'm careful ... I used to put ol' socks over my side rollers before I took them off and threw them under the workbench ... I think they're still there to this day ... 20 yrs later ...)

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

Sorry guys, but the U-bolts are not going to break. Per McMaster Carr, 3/8" U-bolts (the size that's most likely on your trailer crossbars) have a working load limit of 1090 LBS. I'd say that's a very conservative number, the actual breaking strength is probably a couple times higher. Your Hobie 18 weighs 400 Lbs total. Even if 75% of the boat's weight is being carried by the front trailer crossbar, that's 150 Lbs of static load on each of the front U-Bolts. Assuming a 1G vertical acceleration due to bumps, etc, that would be a max of 300 Lbs on a U-bolt which is still WELL below the max load capaicty.

By the way, if you're worried about the U-Bolts on your trailer crossbars failing, you bettern not look under your trailer to see what's hold your axle to the springs...it's U-bolts. And I guarantee the U-bolts holding the axle to the spring see considerably more stress than the crossbar U-bolts everytime you run over a pothole or drive your trailer over a curb.

sm

Yes, It's unlikely that a U-Bolt will fail ... but ... if it does ????

( if it fails ... by the time you STOP the vehicle, assuming you where travelling at speed down the highway ... you have most likely destroyed your boat !!!)

But ... It's more about "hieght", as my front crossbar has been "bent" three different times ... once by me and twice by friends who I lent my trailer too ... by hooking/catching the crossbar on posts ... you have seen them ... old piles/telephone poles stuck in the ground and sticking up maybe 12"-18" ... (they like to line driveways w/ those D*MN things around here, especially in the local/county/state parks). Now once the trailer was empty ... but twice there was a boat on the trailer ... and the post past under the boat but caught/hooked the front crossbar ... no damage to the boat!!! .... luckly, just a ruined "marker light" ... (...or was it not luck ... but fore-thought/preparation .... MMmmmmmm ...)

Now if you haven't noticed ... my last name is MURPHEY ... yes, it is spelled different ... but .... I still believe in MURPHY's LAW ....

then there is ...

The $5.00 part will first fail that then causes the failure of the $1000.00 part ...

or ....

the Irishman's Lament: "If it wasn't for bad luck ... I'ld have no luck at' all ...

and there's also ...

O'Rielly's Postulate: " ... Murphy was an optimist ...."

I try to eliminate ANY & ALL possible failure modes (when possible). I have been stopped by the side of the road w/ bad bearings ... broken mast step ... broken axle ... flat tires ... trailer lights that are not working, etc .... but ... I've been lucky since most (but not all) of the times it has been for my friends that I've stopped to help .... ( I try to learn from my friends misfortunes ... as it is cheaper for me ...)

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

I wouldn't expect the U bolt to break under raw tension, especially when it's new. It's much more likely that one of the nuts would back off under cyclical loading.

The real problem is you have a single mode failure. If you lose 1 nut, you can put the boat on the pavement.

Whereas with the crossbar on top of the frame, you need to lose at least 3 nuts before things go sideways. You're more likely to catch it before something really bad happens.

And yes, Trailex crossbars are slung below the frame - for a very good reason. The aluminum frame members will wear against each other and you'll get holes in them (don't ask me how I know). The attachments are with brackets and at least 6 t-bolts on each side.

As for the axles - on both of my trailers, they are underneath the springs and there are two 7/16" U bolts on each side that just hold them together without tempting gravity.

And those are 9/16" stainless nylock nuts on top.

And I forgot one other BIG reason ... and it is +10 ft long .... and it had to be to store a 9' lg boom and sails ....

My trailer/sail box .... to install it ... to have enough depth, and not have it extend aft past the rear trailer crossbar which then would interfere w/ loading and unloading the boat from the trailer ... (the dolphin striker would hit the top of the box ...), I needed the crossbars to be above the siderails to mount the box, which extends from the rear crossbar of the trailer, forward over and to just in front of were the siderails angle in and meet/join the trailer tongue. And note; it's just right for sliding/storing my beach wheels between the trailer siderails and underside of my sailbox when trailering, I tie the wheels to the front trailer crossbar to keep them in place ... works well ...

So ... it's not just about getting the boat on/off the trailer .... there can be "other" important reasons to be considered ...

(I just realized that I constructed my trailer/sailbox (1/4" Marine Ply/WEST Epoxy) 26yrs ago .... boy, does time pass quickly ....)

( ... and have you noticed Matt's tag ... "Hobie Approved Guru" ... he has earned that ... besides being a "Degree'd Marine Engineer/Univ of Mich(?) ... a smart man ... w/ a lot of "hands-on" experience .... and I do mean A LOT !!!!)

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

I'm not going to go back and forth on this one any further, other than to say again that I see absolutely no reason that the nuts would be any more inclined to loosen with the crossbars under versus over the frame. Use any or a combination of the available thread locking mechanisms out there (loctite, nyloc nuts, lock washer, smacking the threads with a hammer) and you'll be fine. If vibration is an issue, you better check all the nuts on the trailer, not just the ones for the crossbars.

I've got a very old trailer that's got the bars hung under and it hasn't been a problem for over 30 years. Plenty of good reasons to put the bar on top, but probably nearly an equal number for putting it on the bottom. I'm sure the OP has gotten more input from this thread then he ever could have wished for. In the grand scheme of things, this is about the most trivial detail you could worry about, so figure out what works best with your set up and go with it.

And remember, as a wise man once said...opinions are like a$$ holes, everyone's got one and they all stink.

sm