Well, very interesting thread and its good to see I am not the only crazy handy type out there that has the "sure I can, watch me" attitude. I've had a 27 foot shoal draft on a custom bunker-ed triple axle trailer I built for it for 5 years. On-trailer mast raising system. But this shoal draft doesn't sail all that well... was outboard powered, tiller transom mounted rudder, and weekend only quarters. Slept 6 though. Good boat to learn on at our local lake. and like you all, it came home over the winters and on two seasons where I was working away in NM. There really no water in NM to speak of, so I left it home in the shed. It didn't eat a thing over two years. But I wanted to upgrade... started looking and thinking.
Last week I bought a full fin keeled (4'9" draft) 30 ft Seafarer. It has all the upgrade features I wanted... a pedigree hull design, wheel pedestal helm, inboard diesel, full live-aboard systems all functional (H and C pressurized water, real head, shower, 10,000 btu AC, full 110 and 12vt systems, full galley including oven) under hull rudder.
Before buying, I did some calcs and it will fit on the trailer and be less than 13'6" high. Its a 10' beam so I need a wide load permit, but since I did OTR in a semi for three years quite some time ago, I could care less. Its 8900 lb displacement, give or take a little, plus trailer comes in at 12k... so I am good to go on my 1 ton diesel 4x4 dully design limit of 21k and the hitch system's 12k. I'll be adding an exhaust brake and a 4th axle just to have a fully cold brake set in reserve as well as another set of 4500 lb springs to aid in roll stability. The main three 4500 lb axles all are e braked.
10-27-12 Though I'd update you all...
Nope the Seafarer 30 is STILL not home... but I'm working it...
Lots of issues to solve that were not anticipated when I bid the boat...
1) Getting the 27ft off the trailer to free it up. I had checked on this before bidding and was told it was not an issue by the two local marinas here that had traveling lifts. Turned out the marina's on the Ohio River here are not set up for narrow hull deep keeled sailboats and there are reasons... not many under powered sailboats want to play with barges and current, and neither do I... so their lift straps were are simply too long to lift the 27 to a keel height of 44 inches to transfer to my yard dolly (which was on my flatbed to haul home)... ended up building my own lift here at home... sized to also handle the 9000 lbs the new seafarer weighs... Money I hadn't planned on... ~$1600 in material plus two 3 ton chain hoists, but problem solved. Trailer freed.
2) I did decide to upgrade my axles as two were built in 1955 or so and while were the big spindles and cradled by 3" C channel and plenty strong... they appear to look like a mobile home axle derivative and to DOT it would be a hard sell that they were not. The 3rd axle was a mobile home derivative that I built and while it had brand new Dexter 2x12 7K brake system still was a mobile home derivative... still a 6k tube and spindles and I address their weak brakes, but its still a derivative. Read too many horror stories about Maryland and their outlawing of mobile home derived trailer axles... according to them if it walks like a duck and quacks like a duck... its a duck no matter what we rebuild them as. It would be red tagged at the first scale. So I elected to update to three brand new Dexter 7k drop axles with 8 bolt wheels and new tires all the way around... $2700 in all (ouch!!). I also needed to buy fenders as it had none... also a DOT requirement... another $300.
OK... pulled it out to Baltimore to load and haul home (I'd already had the boat put on the hard at a marina as leaving it in a slip was risky with me being 450 miles away)
3) While my calcs were correct for height etc... securely balancing a 9000 lb elephant on one toe is a challenge. Bunkers had to be 48" tall in the middle and 55" on the ends ... and lead to seriously large bracing requirements. While I had modified them at home as best could be without the boat present, and took the welder to secure once adjusted... I felt I did not have enough bracing and bought more angle... BUT I had not taken the torch and was not really able to fabricate properly with proper gussets etc. In addition, my 60 or 70 year old Forney did not like living under a tarp in the pickup and started acting up. Did not trust my welds and it was taking on too much of a cobbled look so I decided against hauling this fall and that I needed to do much more serious modifications to the trailer. REMEMBER, I designed the trailer for a long shallow keel (shoal draft) more or less flat bottomed 27ft Bayliner Buccanner... NOT a 30ft full keeled curved hull Seafarer. Way too much weight on the four 3" C channel cross members where the short 5 ft of keel and 9000 lbs were... bunker way too high to stabilize properly... and the fact that with the slightly larger diameter over slung axles with 3000 lbs more on the springs now left only a 1/2 of travel left till bottoming on the frame (springs were not over loaded, but used much more of their travel that the 6000 lb bayliner did)... just too tight and I was not going to risk my new Dexters... reluctantly, but smartly, I decided this configuration would not work. Mapped the hull and took accurate dimensions off the boat itself (verses extrapolation from a "maybe to scale" drawing)... swore, made arrangements for over wintering there, winterized the boat, and headed back to the house.
So now its rebuild the trailer for THIS boat this winter.
1) Move the axles to an underslung installation (also raises the main frame 4")
2) build a dropped main keel support suitable to the 9000 lbs (less bunker weight) 5" from the ground while maintaining all compression loads and no shear loads on the welds (lowering the boat 15"), going to an independent suspension on the axles while maintaining the ability to slide the whole triple group for weight balance. Yea, it can be done, and have the design already thought through.
3) redesign the bunker support framing and incorporate real screw type support pads...
4) and design for an open rear end frame structure for float on float off.
I'll be busy... but its entirely doable... remember... I built it the first time.
As far as the changes to DOT and permitted loads... WOW it was a PIA but I got it accomplished. Remember anything now (since 2009) with a CGVW of 10001 lbs or more is considered a commercial vehicle and has to conform to 49 CFR.... had I known all this I may not have gone with a 10ft beam. If you want to know I'll pass on what I've learned.... its not like it used to be at all. "non-com" really doesn't exist above 10001 lbs now.
Thought you all might be curious as to my crazy man antics.