Re: C Channel vs. tube trailers ?'s opinions.
.................The main lesson i learnt was that the zinc galvanize coating acts as a sacrificial anode the same way your anodes do on your boat and motor to reduce corrosion at the frame. He said that over time when you start to spot surface rust near the welds and on the bottom of your crossmembers at the rear most part of your trailer that is starting to get to the time to start thinking of re-galvanizing your trailer before the rust starts to really eat at the steel. He said on average with a well used boat that frequents the salt water, the coating will last about 5 years before the critical areas start to get eaten. It makes total sense as you have to replace sacrificial anodes over a curtain time.
This is a part that most people don't understand, galvanization is a sacrificial coating on a trailer. It wears off with age. Even trailer that just sits in the driveway will lose some of its zinc coating with time.
The main reason for tubular trailers is to save weight, you can build a trailer much lighter to haul the same load with tubing and that trailer will be more rigid.
I would not want any length of tubing that I could not flush out or clean.
Yes, open channel frames seem to hold up better but for one, they are made of heavier gauge metal, and they don't have the closed up areas to hold salt. Even an unrinsed C channel trailer will get rinsed off to some degree when it rains. I for the life of me could never figure out why tubular trailers with curved cross members aren't built with a drain, but then again, when they charge $150+ for a new cross member, I sort of get it.
I have had a few trailers re galvanized but it's usually just not worth the work to strip it down and cart it over to the galvanizing plant. I've done a few smaller trailers that I really liked but only because I had a buddy that worked there at the time.
As far as aluminum, I can't say I'm a fan, aluminum has different stress properties and tends to crack. My first experience with an aluminum trailer wasn't a boat trailer but a flat car trailer. In the span of less than two years I had bolts pulled through, corroded fasteners, broken axle brackets, (torsion axles), and many points where bolt heads had worn loose and cut through the frame. This was on a trailer I used occasionally for a few longer trips. I doubt if it ever saw as much as 10,000 miles before I gave up on it.
The dissimilar metal problem with aluminum and likely hood of salt corrosion would steer me away from an aluminum boat trailer. While the weight savings is attractive for longer tows, the long term problems outweigh the cost difference.
I have mostly Load Rite trailers, and have had only few rusted out cross members, but on older trailers. I don't have any real brand preference, and have no problem with galvanized box tubing so long as it's open ended and can be washed out.
My biggest complaint with any trailer is rusty hardware and rusty fenders. I've yet to see a set of fenders last more than a few years here, whether made of galvanized steel, plastic, or aluminum. The steel rusts out from the bottom edges and bolt holes, plastic gets cooked in the sun and cracks, and aluminum corrodes away from dissimilar metal issues.
I've come to the point where I consider fenders sacrificial items as well, I just buy them by the dozen and replace them every two years, or when the rust and fall off.
