Carl, what did it cost to galvanize the tilt trailer in question?

On the issue of trailer STRENGTH.
It is true that very few of us carry more than 1000lbs of weight, but gross capacity is not our biggest problem.
Trailer FLEX is.
Because of the length and center of gravity of our boats, our trailers are very long.
This length causes a great deal of both vertical and lateral flexing while traveling.
The welds and the area around them are especially susceptable to damage from flexing.
I have repaired several of my trailers and helped fix others.
We need STIFF trailers.
If I were building a trailer from scratch, I would make the frame as large and long as possible and add reinforcing plates at the welds.
And have it dip galvanized.

I can't answer that question because I didn't build it, it was built by Texas Tilt (Doug Graf). Doug told me how he did it but, not the cost.

I have helped with smaller trailers (10 years ago) and was told the bids $150 to $600

I have had smaller items galvenized and there was a big difference in the bids (a mast support was $10 to $105) so it pays to shop around.

The best work was done by a big company who "tucked" my job in with a big job for a railroad. The worst job was by a small shop


Some trailer builders that hot dip their own trailers will offer this. I was told a rough rule of thumb was 1.5-2 times the difference in price between a painted and galvenized similiar trailer.

Now you know as much as I do

Comercial galvanizers I know have a $200.00 minimum. The price went up a lot in the last three years. (The EPA charges you for the right to polute). The price is generally figured by the pound. Almost as much as the original steel, so say 25 cents per pound, and a surcharge if it is tubing...so a 300 pound trailer of channel section is $75.00.
The good thing about zinc is that where there is none, the rest gives it an anodic protection?
On trailer design: I'd say that a trailer needs to be as small as possible. It is too long to be "stiff", because even without the boat, it flexes. Clearly the payload is not the issue with flexture. A drawbar that attached to the front crossbar (where the weight acts)with a minimal support to the back crossbar and mast cradle, with a rubax type independent axle would be the way I'd go. Some sort of rotating arms to secure/ lower the boat to the ground, and then drive the trailer out, would be my route.

Carl,

There are a group of Southern CA Tornado owners working out plans to get 3 or 4 Tornado tilt trailers built in the next month or two. We have a few concepts that look promising. One involves an all aluminum trailer for good corrosion resistance and a "crane" post that will hoist the boat up via the main beam/hull intersection point, up into an upsidedown beam cradle fixed the the top of the crane post. The high side will then hang from this cradle only...no other support posts will be needed since the main beam is so close to the balance point of the whole boat. The lower hull will be strapped into pivoting hull cradles and thus provide all the other hold down stability needed. This has advantage of keeping weight aloft to an absolute minimum. If more weight is wanted down low for stability, a good sized storage box could be added etc.

Can you provide us any details on your trailer? Pics? Drawings? Doug Graf's contact?

Mike.

Greg Scace from CRAC maybe able to help you - I believe he has a pretty good design he came up with. Grabs the boat by the crossbeams, it gets winched up to rest upside-down supported by the beams, not the hulls.

I'm familar with the Scace design...unfortunately we all want a trailer we can also use to launch the boat off of directly. The upside down tilt type does'nt meet this requirement.

I like the scace design, unfortunately, there are other trailer designs that are far simpler to build, and less expensive that meet the above criteria.

Mike

It would hard to make a picture of the trailer right now, everything is covered for the winter. I will see what I have in the library. Design wise the trailer is standard. A reinforced "A" frame with a tongue. The tilt platform is an H with telescoping arms (so you can trailer the boat flat) with steel cradles for the hulls.The real difference is in construction. It was built like a commercial trailer. For a cat trailer it is a monster. It uses 2x6 for the lower frame, 2 1/4x2 1/4 & 2x2 for the upper and what looks like 3 in drill casing for an axel. Empty and bare it probably weighs around 1000 lbs

Your design uses the boat as the tilt platform. Steel trailers, hinges, etc damp road vibration and raise the resonance frequency. You are going to have to worry about resonance frequencies. If I don't tie my upper hull tight, it vibrates in the 0-10 hertz range.

I do not recommend launching a Tornado off a tilt trailer. It is hard enough keeping the corrosion off the expensive bits without dunking them in saltwater.


The US Tornado Assoc used to have plans for a good tilt trailer. Contact the US Sec to check.

The plans were detailed. They told you how long to cut what and how to weld, etc. Basically you could go to a self service steel yard and cut the parts. Then take them to a welding shop. Finally to galvanizer and then put it together.

When I first started, I wanted something like you are talking about. I was looking at a welded Aluminum or an aluminum upper with a steel lower. When I talked to trailer building professionals they talked about cracking problems with welded aluminum, transmission of vibration, galvanic corrosion at the hinge, and how the aero loads are dominant for the upper section. When I talked to an owner, he talked about sway, vibration and loosening hulls.

After living with the trailer for a while, I have decided that Isolating your boat from loads, stability in cross winds, ease of operation, reliability, and protecting that expensive hydraulic system is more important.

If I were going to build a trailer, I would look at the upside down system. A friend built one years ago. He claimed he might not be the fastest Tornado on the water but, he would be the fastest back on the trailer and he was.

I have the same reservations that you do about this design. I'm not sure I like the boat being the tilting frame itself. Not sure I like the raised hull just up there unsupported. I'm definitely going to build mine out of steel.

Regarding using the boat structure itself as the tilting frame, it was mentioned on the tornado group that because you have a rack itself does not isolate it from flexing. However, I think that a steel rack with diagonal tensioning rods would flex less than a free standing unsupported flying hull. They say the loads on it would be much less than a boat crashing through a wave, but I'm still a bit skeptic.

Guys,

It's exactly the very slight flexing of an "H" type tilt bed that can damage the beams. When you support the hulls in snug fitting cradles where the cradles are connected by metal beams...any bending along the lateral tiltbed beams will tend to cause the cradles to pry the hulls apart in a direction that the hull/beam structure is not designed to handle. Even very slight bending can do damage and over many trips, this can(has) lead to boat failures.

Our hanging-from-the-mainbeam concept eliminates this risk entirely, since flex of the trailer cannot be applied between the two hulls. THe mainbeam is quite close to the balance point, so any windage or road bump loading on the ~80 lbs lifted hull should be easily handled by the structure. A structure designed to slam into waves and come to a rapid stop from 20+ kts speed (easily hundreds of lbs loading) is not going to be affected significantly by 60 mph winds from straight ahead while driving on the freeway. Many of these mainbeam support designs were built in the 70's for Tornados with no reports of problems.

Mike.

how about a rack that attaches not to the hulls, but rather the beams themselves... much like the scace design.

I'm not saying that your trailer is unsafe or dangerous, I'm just curious if there is a better mousetrap.

how about a rack that attaches not to the hulls, but rather the beams themselves... much like the scace design.

David Tilley, who has contributed to this thread, has designed a quite interesting tilting trailer. I have the second of the prototypes, and on the whole am VERY pleased. This trailer has easily several thousand miles on it with only two failures, and those due to the base (OLD conventional cat trailer - the leaf springs failed, and not catastrophically). That would be easily rectified by either fabricating a strong Aframe or using a powerboat trailer Aframe to start with.

Go have a look at Tilley's trailer:
http://tinyurl.com/nlva


sea ya
tami

Sorry, you have to log in to get the first reference. Here's another, and you can just go there:

http://tinyurl.com/w97w

sea ya
tami

tami:

I think I like that design the best. One question though. When "un-tilting" the boat, do you have to push it up to get it to come to vertical? I remember on the scace, Kevin and I had to push it a bit once it got vertical to make the winch to start working in the opposite direction.

Thanks! You wouldn't happen to have plans for this design would you?

Do have to push a bit. If you look at the pics at the TheBeachcats.com site (not the Yahoo Beachcats) and read the comments, they elaborate on its handling, and give contact info for Dave Tilley

Dave, hope you don't mind me plugging your work, I know you're monitoring this thread...


sea ya
tami

If you can handle a Cadkey or at least a dxf file, send me your US Postal address. I got a new print cartridge rearing to go, and it is all 8 1/2 x 11 cutsheets.
No charge and no liability.
(I have painted my trailer now, and may even post some pictures in action)
Carl, you really got me worried about Upper Hull Flutter now. Could you calc it if I tell you the torsional resistance of the crossbeam and the distance from hull to clamp? I guess if I stay under 120 I'll be OK? Don't give me that "I'm too busy 'cus Bush says we gotta go to the moon again" They did it with slide rules last time.