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PostPosted: Wed Apr 11, 2012 10:54 am 
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Hi Guys,

Thanks for all the input. You've certainly given me a few things to think about.
- Regarding the u-bolts and nuts...if I was worried about them (which I don't think I am), I could use a bolting plate and use two u-bolts per joint. Cheap insurance against the worst-case scenario.
- Sail box clearance...that's a good one. Gotta take another measurement to see if one would clear on either side of the dolphin striker.
- Road debris, etc...not sure 5" would make a difference, but it could.

Thanks Again!

Mark

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PostPosted: Wed Apr 11, 2012 10:58 pm 
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Hi,

Some of the "catboxes" will fit on one side of the trailer under the boat ...but opening the top can still be difficult. I built a "custom" sailbox 24" wide X 16" high X 10' lg. I also designed it w/ a top that can be either slide off (aft) or be lifted off when the boat is not on the trailer. ( I thought I built it large enough ... but ... with (2) sets of sails, (1) set of dagger boards, complete rudder system {I did say I am protective of my EPOV1's}, tool box, spare parts (tool)box, milk crate w/ line/bungie/misc, boom, bicycle air pump, paddles, spare battens, life jackets, harnesses .... etc, and I now think I should have built it larger ...)

Now if the sailbox wasn't 10' lg to hold the 9' lg boom and rolled up sails it would have very been easy to just mount the sailbox w/ the crossbars under the siderails and just butt up the sailbox to the Y were the siderails meet the trailer tongue and size it so as to be just to the rear crossbar .... but .... I wanted it to hold my boom and sails or else it was of limited use to me. And I didn't want the sailbox to extend aft of the trailer's rear crossbar, because that can make it difficult to unload or load a boat on the trailer. You usually need to pull the boat far enough aft so that the dolphin striker is completely clear of the sailbox before you can lowwer the sterns down. So I measured from my rear crossbar on the trailer 10' forward .... figured were the front end of the sailbox would extend too .... (slightly forward of the "Y" on my "Hosclaw") .... did some simple mathmatical calculations .... and quickly confirmed/determined I needed the crossbars on top ... combined w/ double stacked (2) 2"X8"X16" lg laying horizontially bolted to the trailer crossbars to give me the clearence I need.

Maybe that is the real reason most of us that race on the "Hobie" circut, have our trailers configured w/ the crossbars on top .... since most of us generally have trailer boxes for storage. We are traveling a lot and it is best to have everything in a "neat" rig that you just "hook up" and drive away ...

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PostPosted: Thu Apr 12, 2012 6:19 am 
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I measured everything last night and I currently have 20" clearance from the bottom of the dolphin striker to the top of the top-mounted crossbars. If I move the crossbar to be below the frame, the boat goes down 5" but now the 2" crossbar isn't in the way, so I only loose 3" of clearance leaving a total of 17". With the clearance increasing as you go outward towards the hulls, I think I'd still have room for a sailbox.

Thanks,

Mark

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PostPosted: Thu Apr 12, 2012 1:41 pm 
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Hi Mark,

That's great that you have enough vertical clearence ... the cradles I think actually raise the boat up higher then rollers on the trailer ....

... now the question is do you have enough "length" for a 10' lg trailer/sail box .... and remember what I said about why I didn't want my trailer/sail box overhanging aft of the rear crossbar of the trailer.

You may wish to take some measurements by taking the boat halfway off the trailer and setting the sterns on the ground .... then checking the "dolphin Striker" clearence ... you maybe able to have a small short overhang ... please note that H16's have more clearence for the dolphin striker since the tramp sits up on the corner posts so you can't use a H16 w/ trailer and sailbox for exact measurements, many H-16's do have their sailboxes extending aft past the rear trailer crossbar for a short distance Note that a H18 sailbox needs to be longer since the boom and sail (when rolled/bagged) are longer then a H16's.

Now there is another option ... construct a sailbox that fits into the "Y" .... but that's a little more difficult then constructing a simple square sailbox w/ a flat bottom ... (... but I did explore that idea at one time ...)

So take a measurement forward from the rear trailer crossbar ... you can even allow for a 1' overhang if you wish (I don't recommend any further) .... and see were you end up .... (I can come up w/ a rough estimate from your pic .... let me know what it is actually ...)

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PostPosted: Fri Apr 13, 2012 5:06 am 
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Some of you guys sure at fatalistic about some bolts. I guess this millions of cars in SUA configurations, with SPLIT washers have tons of problems?

Anyways, I would not want my boat any lower, it seems ideal that it would be high enough that the daggers or rudders would not hit if they fall.

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PostPosted: Fri Apr 13, 2012 6:45 am 
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Mornin',

Both Matt and I both went through "Engineering Programs" at college. I know in Drexel's CO-OP program we had 18 months of actual "on the job" engineering experience before graduating. And in the real world of engineering there is a word .... "REDUNDENCY" .... basically always have an alternate/back-up ... a "out" if you will.

So the issue is ... if you have the crossbars under ... and only one bolt/nut (maybe $3.00 ...) is holding it .... and it does fail .... you may destroy a boat worth .... Thousands of Dollars!!!!!

If you look at the cost ratios between the bolt/nut ... and the resulting "possible" damage .... let's just say "it's better safe then sorry ..." at that price.

I base many of my decisions (in life) on these rules ... ex: Motoring back at night in bad weather from a long distance "Big Boat" regatta ... need fuel ... have one harbor/fuel dock close that we were familiar w/ and will arrive w/ 1/4 tank of fuel remaining , the other is at the very end of our estimated fuel range and I had never navigated into before ... Now, which one do you think as "Navigator" I suggested we go for ???

... so the more dire the consequences ... the more important is this rule ...

.... NEVER (EVER) LEAVE YOURSELF WITHOUT A "SAFE" OUT/ALTERNATIVE ....

( ... as for all those millions of cars w/ split lockwashers .... there is 99.9% of the time more then a single piece of "hardware" keeping it together ===> redundency !!!)

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PostPosted: Fri Apr 13, 2012 3:03 pm 
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Harry Murphey wrote:

( ... as for all those millions of cars w/ split lockwashers .... there is 99.9% of the time more then a single piece of "hardware" keeping it together ===> redundency !!!)



Yes, one u-bolt has 2 nuts and lock washers, 2 u-bolts on each corner gives you 4 chances to escape failure.

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PostPosted: Fri Apr 13, 2012 4:15 pm 
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Bacho wrote:
Yes, one u-bolt has 2 nuts and lock washers, 2 u-bolts on each corner gives you 4 chances to escape failure.

That's not how it works (at least if the crossbar is on the bottom).

You lose 1 nut and the cross plate is now loose, which allows the second nut to work loose much faster. Once you lose the cross plate, the crossboar sags down and puts your boat on the pavement.

Here's the link to the NASA study that proves that split washers - "lock washers" - are basically not worth the metal they're stamped from: http://ntrs.nasa.gov/archive/nasa/casi. ... 009424.pdf


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PostPosted: Sat Apr 14, 2012 5:11 am 
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that's an interesting theory NASA states about helical spring washers. however there is no mention at all of what the helical spring actually does: provide upward force against the threads when fully flattened to prevent the nut backing off.

In some high temperature applications I have seen helical spring washers lose all of their shape due to re-tempering of the metal. not a good scenario.

I'd agree in the most critical application the best solution would be a tapered nut.

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PostPosted: Sun Apr 15, 2012 10:17 am 
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Guys,

My Hosclaw trailer has only (1) U-Bolt per corner holding the crossbar on. It is installed diagonally across the crossbar/siderail w/ a bottom plate, (2) nuts and lockwashers .... so ... in my case if the U-Bolt fatiques, fails and falls off .... I have nothing holding the crossbar SECURELY in place. If I lose a "nut" but still have the U-Bolt, I HOPEFULLY would/will notice it before something REALLY REALLY BAD has happened. If the crossbars are slung under .... I have even less time to discover the problem and fix it before it costs me ALOT more $$$$'s then just a U-Bolt and nuts/lockwashers ...

I have trailered over the years a estimated 100,000 miles w/ my catamarans following me in my rearview mirrors from Mass to Hatteras North Carolina and even out to Cleveland (yes, I went to Cleveland for a Hobie Points Regatta ...) almost every weekend from April to November ... for years/decades .... alot of those miles were done at night and at "highway" speeds. I don't know how many miles Matt has trailered .... but he lives in Michigan ... has attended Hobie Points events here on the "East Coast" were I met Matt ... attended Hobie events all over the Midwest ... on the "West Coast" .... the "Gulf Coast" .... and Canada (I suspect).

It is one thing to "trailer" locally from your house to the "local" beach a couple of miles away ... a few times a year. It is another whole kettle of fish to "trailer" the kinds of milage Matt has or even I have ... over the years ....

And that's why we have developed/assembled our "rigs", as we have .... and all we are trying to do is pass on our "hard" learned knowledge that has cost us alot of ... Driving Time, Gas Money, Tire Rubber, etc .... but luckly no boats ...

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PostPosted: Sun Apr 15, 2012 12:06 pm 
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I can't believe anyone uses the "standard" catamaran trailers. Zero protection.


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PostPosted: Sun Apr 15, 2012 10:53 pm 
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I may be visualizing this wrong, but won't moving it underneath only give you an additional 3 inches, not 5? The cradles are still going to be mounted on the tops of the crossbeams, so the only distance you are lowering is the 3 inches right?


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PostPosted: Mon Apr 16, 2012 4:16 am 
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ryman522 wrote:
I may be visualizing this wrong, but won't moving it underneath only give you an additional 3 inches, not 5? The cradles are still going to be mounted on the tops of the crossbeams, so the only distance you are lowering is the 3 inches right?


The cradles are relative to the top of the crossbeam. The distance from the underside of the frame to the top of the crossbeam is the frame + the crossbeam height, so 5 inches is correct.


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PostPosted: Mon Apr 16, 2012 4:31 am 
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Karl Brogger wrote:
I can't believe anyone uses the "standard" catamaran trailers. Zero protection.

OK, I'll bite. Please enlighten us as to your protection methods. We all know of Magnum protection, but CVS doesn't have the same availability of SE or SX protection. :)
..... and no armour plated hovercrafts - too obvious!


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PostPosted: Tue Apr 17, 2012 4:40 pm 
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SimonP wrote:
OK, I'll bite. Please enlighten us as to your protection methods. We all know of Magnum protection, but CVS doesn't have the same availability of SE or SX protection. :)
..... and no armour plated hovercrafts - too obvious!


I like the armor plated hovercraft idea.... At the very least an APC would be nice.


First off, I'm a road warrior. I put on probably 15k miles last year pulling boats around. Which is excessive and out of the norm for me, but 7500 miles a year isn't out of the question.
My first catamaran, (an 85' H16), came with a very worn out Trailex trailer, that I sold with that boat. My next trailer was a pretty standard steel framed cat trailer that came with a H14, and it served double duty with my H16. In 2008 I had an aluminum trailer built. It was frickin' sweet, held my jetski and the boat nice but then I started looking at it, and thinking about how the bows are just hanging out in space catching everything that the vehicle kicked up, and how there was nothing to prevent a blown trailer tire from knocking a hole in the bottom of the boat, and I do hear of that happening on a fairly regular basis. Plus the trailer I had built was so loaded with composite decking that there wasn't a comfortable amount of weight capacity left on the axle to handle a rack and a second boat.

I wanted a trailer that had tandem axles for a couple of reasons. Tandems track much nicer, and if you nuke a bearing a long ways from anywhere, on a holiday weekend, in the middle of the night, at least you can limp somewhere on three tires. I ended up buying a 20' flatbed with a 5k pound capacity, tandem torsion axles, and I had an aluminum rack for the double/triple stack with a rear mast stand. The masts lay flat, so there's lest windage.

Image


I haven't gotten around to building a proper sailbox yet. I kept wanting to have an aluminum one built, but I'm ballparking it to cost around $3k, and I'm just too poor for that. The box is going to make a "T" shape, and follow the v at the front of the trailer. It'll end up being 13' long, 8-1/2' ft wide at the front. The front section is going to be a bit more than 3' tall and that's where the real protection is going to come from. It would take something pretty dang serious to injure the bottom boat. These frickin' things are $25,000 and don't like mis-treatment, so why risk it with inadequate trailer?


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