Trailer question

I have two cats and two trailers right now, and I want to swap the trailers as the one which came with my Nacra is more recent and lighter to move around.

In order to do so I have to install new hull cradles on the cross bars and so on. But I was looking at the A class trailers on the parking lot at Grafham this week-end and they do not use hull cradles at all, they use beam supports (because I assume the hulls of an A class are too thin and light to be strapped down on cradles). Somewhat similar to the system on this roof rack.

Anybody tried such a system on a F16 trailer? pro? cons?

there is no reason why you couldn't do that with an F16, though you should look at your dolphin striker and see how far out to the hulls the V goes. This would make it difficult to put a support there because it would interfere, although there are ways around even that. A lot of A cats don't have dolphin strikers so it is easier to do it with them than other cats. Another issue would be how difficult it is to get the boat on and off the trailer with those type of supports.
I would like to do it on mine but don't have that much time to modify it. I also don't generally trailer that much so I don't see it as an issue. The 400lb boats handle the cradles well, the F16 handles it well too though I am much more careful to make sure the rollers in the rear are well padded.

go to Page 5 & 6

There is no dolphin striker on my Stealth. Easy

Excellent link. Thanks.

Hi Pepin

I'm currently in the process of converting my 'std' trailer into one in which the Capricorn will rest on its beams. I'm having a frame made up which will then bolt to the road base with two rails for the beams to slide on. If things go to plan might all be done in a few weeks so could email you some photos. Like to cost around £250 to convert from the existing base. Like you I picked up the interest from the A's, if nothing else it will make the trailer less bulky for storing when the boat is not on it.

Do you feel the structural design of the beam-hull bolting system was meant to support the DOWNWARD force of hanging your hulls? The entire weight of a bouncing hull being trailered would be held up by the treaded mount in a fiberglass deck lid and hull socket. It might not matter with a 165 pound A-Cat but a 400 pound F18 could be more than the joint was designed for. I could see a disasterous ripping out and dropping off a hull as you bounced over some railroad track crossing. Yikes!

David:
And do you not fear for this connection when you have 380 pounds of crew weight sitting on the same hull when it lifts out of the water?

I would suspect that a connection that can handle hull flying will be capable of "flying" crewless while being trailered.

After reading how others have done it I ended up with the attached. The beams slide well along the "plastic" lumber and the dolphin striker drops into notches at the front. This takes care of any fore/aft movement. When the rear mast support is unpinned and removed, the rear of the frame lowers to the ground. This reduces the amount the boat needs to be lifted to get it onto the trailer.
In these photo's the boat was loaded onto the trailer for the 300 yard trip from the sail club to my cottage.

I'm in agreement with Bobcat. An analagy...

My Dad was considered a Maverick, in the early 50's, when he left his V-4 outboard motor on the transom of his boat while trailering. "They" said it'd be laying in the road with the back half of his newly built boat. Everybody took their motors off the boat and put it in the trunk of the car, a two man job.

I'd advise against supporting any bolted boat by the beams. When you fly a hull the hull is pushing up on the beams not bouncing down a road hanging off them. Hanging the hulls on the trailer will definately soften the composite structure around the beam landings and shorten the competitive life of the boat.

A's can do it because they're A. light and B. Glued.

I can see where you are coming from....the sidestay is doing the heavy lifting. But then again, so isn't the mainsheet also lifting the beam. So, the bolts are sized for the beam torque, not the weight of the guys standing at the back of the bus?

Is the composite structure at the sidestay that much superior to the structure at the beam landings? Some mode conversion here I guess. The sidestay is in shear, while the beams are compression/tension.

Hanging off the beams while trailering would put the beam bolts in tension, while the normal mode is compression. So, the nuts are at risk of pulling through?

Just trying to get my head around it.

If you've tensioned the bolts up properly, they will remain in tension throughout the usual range of loadings. The bolts are so much greater in diameter than the sidestay wire, it isn't worth thinking about.

Its not the bolts that stop me from doing this on my boats, its the composite structure around the beam landings which will become softened over time due to vibration etc. Also I'm not suggesting that the boat will fall off the beams, merely that its competitive life will be shortened.

Sorry mate, quote added for reference. You're right, the bolts will not be a problem.

Although to be honest, I'm not convinced the softening of the beam landings is a major concern with a trailer setup like this. Relatively speaking, travel is only a fraction of the sailing time, and sailing would be putting more stress on the area with the torque loads...well certainly where I sail, the chop is nasty!

Agreed, but it all adds up.

Never had a problem with my bolted Taipan over several thousand miles on my beam-supporting trailer. I would check the bolts from time to time and they were always torqued as expected. Also, the boat is as stiff today as new.

The hull only weights 23.5 kg (50 lbs), that is not a lot to hang from 2 (or 4) M8 bolts or even a typical laminate work.

Of course the same reasoning can be reversed. I rather hang 23.5 kg from the bolts and the reinforce area around the bolts then press against the (unreingorced) keel line by the same amount.

It is laminate up there, but also laminate down there. So what is the gain/loss ?

Wouter

Can't comment on the other F16's but Jim Boyer, who built the hulls for my and all the older Taipans at least, definitely recommended trailering from the beams- in fact, I was told if you trailered with boat supported on the hulls it would void the warranty even! Jim was more concerned about the boat "racking" during trailering and being "squeezed" by straps over the hulls/beams down to frame to hold boat on the cradles than the hulls "hanging" off the bolts. Jim therefore recommended a stout, heavy steel trailer (softer ride and less twisting) and supporting the boat by the beams. My boat is supported by the front beam at the inside corners but only in the middle of the rear beam (ie a triangle) precisely to prevent "racking" of the boat if the trailer does twist going down the road. Most of the weight of the boat is supported by the front beam- I would guess there is only about 20-30 lbs. maybe being supported by my rear beam in a static situation. If it was good enough for Jim it's good enough for me!

Kirt

What about this, cover the trailer with plywood, add foam to where the hulls will rest, thus making it like a flatbed type trailer, so the hull is supported along its full length rather than just at two points, front and rear?

Would maybe work if the hulls were flat bottomed. The bottom of my Stealth has quite a lot of rocker front to back so I'm not sure it's a good idea: it will probably end up with one pressure point in the middle instead of a constant equal pressure all around. You can do that with a Wave or a Nacra 500 maybe, but it doesn't seems like a good idea for my boat.

Well what I meant to say was to cut the foam to fit the entire length of the hull, so there is no single pressure point. I have seen this done with several trailors, some A cats and others.

Oh, I see! Quite a lot of foam to find and cut. And boats don't slide that well on foam so loading and unloading might be interesting. But still, interesting idea...

Timbo-
Actually, for the NACRA 5.0 I had for 17 years I had long 2x6's that were covered with carpet pads and carpet and it worked great for that boat as the bottom of the hulls were literally straight! Probably the "ideal" would be a flatbed of sorts as you suggest but carrying the boat upside down supported on the front beam and rear beam in the middle with high density foam beneath the entire front beam and middle of the rear beam with foam cutouts under the bows. That way the hulls are bearing down on the beams so no "hanging" of the hulls at all and no loadbearing except where hulls are designed for it. Only problem is the PITA one would have to go through unless you developed a simple/reliable system to "flip" the boat onto the trailer-

Kirt

My boat is stored mast up on its trailer 99% of the time. Flipping it on its trailer is completely out of the question for me

I've seen it done. Twice.

I also have multiple boats & multiple trailers. My solution for versatility is to install a 2" straight roller on each side of the rear trailer beam that is 17.5" long. (Rollers are 13.5" plus 2" endcaps on each end). Once the boat is on the trailer, put a cradle under the rear hull that fits over the roller. The cradles also fit the cat trax axle and the 2" trailer beam in front. (These are not the Cat Trax cradles) Because the cradles are not attached, I can move them in and out to accommodate boats of various widths. The 2" straight rollers are available at West Marine, Bass Pro and other boating / trailer supply stores. Shipshape makes the rollers in 9" sections. Get 3 rollers and cut one in half. Use 1 and 1/2 roller on each side with endcaps.