Small boat trailer design w/light suspension, folding, good support?

[Thorne]

Inspired by another thread here, I was wondering what we can (or already have) design for a quality home-built boat trailer?

Requirements:
1. No welding or heavy machinery processing (like pipe bending)
2. Reliable/commercial axle, bearings, with stock wheels
3. Suspension for boats under 500lbs possibly under 350lbs
4. Length & support for 12-18' wooden hull

Optional "nice to have" elements:
a. Folding or removable tongue
b. Rustproof in part
c. Minimal height for easy launch/retrieval
d. 12" wheels for better long-distance towing

I've never read the Glen-L book on building wood-frame trailers, and am not too sure how the DMV would like that, but am willing to consider all or partial wood frame elements.

Not willing to consider torsion axles, or suspension systems rated for 1000+lbs, both of which seem to be the only lightweight ones readily available from Northern Tool and other major retailers. I've owned an old Holsclaw and loved the coil-spring & auto shock suspension, so something similar would be wonderful!

The folding or removable tongue system needs to be bombproof - I have no interest in trailers that might put the boat and/or other motorists at risk.

I understand that commercial trailers exist with all or most of these elements, but prices are usually well over $1200 for the Trailex aluminum models with spare tire, winch stand and winch. Bunks would have to be purchased and installed separately.


http://www.boatownersworld.com/trailex/sut_350_s.htm


http://www.boatownersworld.com/trailex/sut_500_s.htm

[dredbob]

Assuming you can find an acceptable spring/axle assembly, something like the Kee Klamp or Nurail or other structural pipe fittings might be something to look at using. I'm sure the standard set screws would have to be replaced with something that could stand rattling down the road, but the strengths of the fittings are probably up to the job, using say 2 inch pipe or bigger.

Bob

[Dave Wright]

I'm guessing you want a very lightweight trailer. I think it might be problematic to specify "Reliable/commercial axle, bearings, with stock wheels," at least as we commonly think of them. It would be nice to have a very lightweight trailer for a very lightweight (say 350 pound) boat, but stock hardware tends to be heavy. Maybe what we're really searching for is very economical, lightweight but durable rolling parts. The Yakima Rack and Roll seems to do this but at an unacceptably high price. I guess I'd be searching for similar rolling parts at reasonable cost. Aluminum frame members are cheap and easy to work up.

[gibetheridge]

If the main spar were made of wood, hollow, thru bolted and glued and with a solid telescoping inner spar it would facilitate launching at shallow launches.

[Thorne]

If the main spar were made of wood, hollow, thru bolted and glued and with a solid telescoping inner spar it would facilitate launching at shallow launches.

It wouldn't be remotely strong enough to handle the weight and forces of trailering unless it was massively thick! Please be serious here, I'm looking for a functional and safe design, hopefully for those who have very limited storage space or equally limited budgets - but still want a quality safe way to transport and launch their wooden boats.

Building a removable metal tongue is relatively easy - just get a 3' collar cut from the next largest size of pipe or square metal tubing (to match the existing tongue), drill and bolt it permanently to one end of the tongue, use big SS bolts to attach it temporarily to the other end, with lock washers and/or safety pin.

As for something like the Yakima trailer, that would be great if we could source the parts separately. But I'm concerned that the Yakima frame support / suspension design (only rated for 250lbs) might encourage 'hopping' on rough roads -- same problem with torsion suspension, as I can attest that it is VERY bad about hopping unless loaded within 60-80% of max weight.

My Aeroflow trailer has torsion suspension, and is scary to tow empty as it will do repeated 3' vertical hops on bad freeway sections. It but handles a near-max load very nicely.


Here are some photos from riversailor.com of his Holsclaw suspension-

[Dave Wright]

Look, you have to be pragmatic about this. Evaluate how many miles you will ACTUALLY use the lightweight boat trailer. Chances are the usage will be minimal. The Yakima Rack and Roll weighs 150 pounds and only carries 250 pounds and is ridiculously high in price.. You search for lightweight rolling stock versus price and availability and there's only one rational conclusion for light weight use, low cost and general availability: Use 8 inch wheels and tires.

Get this to start, 151 pounds weight, 600 pounds capacity and $330: http://www.harborfreight.com/automot...ires-5002.html

Remember, once you get the trailer license and title you can modify or upgrade it virtually anyway you want with no hassle from the authorities. Easier than starting from scratch and getting title and registration - I've been that route. Best wishes.

[Todd Bradshaw]

Actually, that would be MY Holsclaw suspension....only at the moment it's sitting out next to the garage with the iceboat on it instead of the kayak cradles. If you want views that are detailed enough to build one from, they're in the "Holsclaw" folder here:
http://webpages.charter.net/tbradshaw/
Save them to your computer if you want copies, as things tend to come and go when I need space on the website. It's a superb trailer and nothing using leaf springs will ever even be remotely close when it comes to a smooth, quiet ride. Does the Yakima really weigh 150 lbs? I'd be surprised if mine weighs much more than that. I can pick it up if I have to move it sideways. Back when I used to sell them, the capacity on most of the Holsclaws in that size range was 500-600 lbs. but we haven't put that much weight on it. So far over the years we've used it for a Sunfish, a Speedball (like a Laser II), a 12' Avon sportboat with an 18hp Nissan on the back, the iceboat (maybe 150 lbs.) and the kayaks (two singles and a double) or sometimes two singles and my Old Town Guide canoe, totalling 160-180 lbs. It's worked great for all of them and you literally have to keep reminding yourself that you're pulling a trailer because it's so quiet. When was the last time you had to do that with leaf springs?

We see a couple of those gorgeous light aluminum trailers with motorcycle wheels every year at the big canoe shows, but a couple grand for a little trailer is far more than I'd ever spend on one.

[Nicholas Scheuer]

I've modified several trailers that I've bought cheap. They usually turned out comparatively heavy, but the price was an acceptable tradeoff.

IMHO Dave Wright has the best approach posted here. That trailer is cheap, and it'll transport a light boat very well. What's not to like?

If you want something else, settle on the running gear first, then design around that. Starting with the suspension and wheels will settle the question of coil springs or leaf, and leaf for-n-aft or transverse. You can't design a frame without choosing suspension first.

[John Turpin]

This is my winter project. Around here, finding an acceptable boat trailer is difficult. Last year, I gave up and bought a used trailer that probably should have gone under a heavy bass boat instead of my little wooden sailboat. The thing weighs a ton. So, I've been keeping an eye out for better trailers. About a month ago, I found an ad on Craigslist for an aluminum trailer. When I went to see it, it turned out to be a Trailex Ultralight boat trailer of unknown age. This is the company that makes the trailers at the very top of this thread. This trailer is all aluminum channel that's bolted together with plates and special channel T-bolts. It's perfect for what I need and is a much better match for my light boat. I've replaced the lights and winch and bunks. I'm also replacing the light axle and 12" wheels with a 2000# axle and 13" wheels/tires. When I get done, I should have a pretty nice little aluminum trailer. But, these things sure are hard to find; at least around here.

[Keith Wilson]

I've converted two of these for small boat trailers, using a long steel tube for an extended tongue and wooden homemade bunks. Their main virtue is that they're very cheap ($180) and easily modified (all bolt-together). Wheels and bearings are standard trailer stuff. The springs aren't too awful if you take out one of the two leaves, but it bangs and rattles and will never be as nice as the coil spring/shock absorber arrangement above. It will rust even in fresh water, but slowly. There are many nicer trailers, but few cheaper; not bad if you aren't a perfectionist.

[Rob Hazard]

One of your criteria for this trailer is foldability. Why? Where is the boat when you fold up your trailer?

[Breakaway]

He mentioned a swinging or removable tongue, which some prefer because it shortens the whole package, making it easier to store.

Kevin

[rkeller]

Hi Thorne:
I saw something similar to what you are talking about. It was a small wooden trailer with narrow motorcycle wire rims/tires and curved metal fenders with torsion bars instead of leaf springs. It was homemade and gorgeous. The owner was an aircraft mechanic who said even small leaf springs were to "springy" for his small wooden boat (approx 15') and would bounce it around too much. The torsion bars were L shaped round metal bars and the wood was two spruce bent spar looking pieces that swept back from the hitch point arcing nicely to the axle then on to another curved wooden tailpiece. It looked simple and elegant.
I google searched for something similar but found nothing. If I could source some nice inexpensive lightweight spoked wheels I'd give it a go, especially for a lightweight boat.
Good Luck.
Russ

[Lewisboater]

I'll second the harbor freight one...I have one and it works very well. Changed the tires to the larger high flotation ones to give the bearings a break but I have used it for oh...5 years now with the only issue being I used those stupid supplied crimp taps instead of wiring it properly...but wiring never seems to last more than a few years anyways.

[slidercat]

I used a Harbor Freight trailer for several years, but even though I always rinsed it after each launch into salt water, it eventually rusted into uselessness. So I kept my eyes open and eventually found a used galvanized trailer for a couple hundred bucks.

These trailers seem to vary a lot. Mine is very hefty, but a guy who built a Slider sister ship found a johnboat trailer that was narrow enough that the hulls sit outside the wheels, so that he can use a much shallower ramp than I can. A johnboat trailer would probably be more suitable for those light boats, and often you can find a johnboat and trailer for very little money.

[Thorne]

Not interested in the Harbor Freight option, as I've owned two and (sorry guys!) they were crap! Metal parts falling off, breaking during installation, bearing failures at bad times, and rusting rusting rusting! Quality (and part sizes) vary in the Chinese trailers, but none of the trailer shops around here will touch 'em -- so they do NOT always take "standard trailer parts".

Their suspension is rated for around 1000lbs (the Feds made them drop the rating from 1350lbs after multiple failures and accidents), and is WAY too stiff for a lightweight wooden boat. That is why I spec'd lightweight suspension in the initial post on this thread.

I trailer a lot of miles annually, which is another reason why I spec'd commercial axles, bearings and wheels. A single round trip to Oregon will often be more than 1100 miles, plus I trailer up to Humboldt County at least 3 times a year for an additional 1800 miles. Trips to Elkhorn Slough, various destinations in the Delta, and multiple boating weekends in Tomales Bay will add another 800 miles at least. Do I want to risk my boat and other motorists pulling a crap trailer with dodgy bearings for nearly 4000 miles annually -- NO!

And yes I got the utility trailer and replaced the entire tongue/backbone with a heavier piece, replaced the fenders when they fell off, replaced the axle when the bearings and spindles were junk, etc.


That is not to say that HF trailers don't have their place, and I see a lot of them in use by boaters who do under 1000 miles of trailering a year. Many of the TSCA folks who have 'em are unwilling to even get the axle and bearings wet, as they have light ply boats that can be lifted on & off the trailer at the water's edge. My solid wood boat is far too heavy for this, so my galvanized EZLoader trailer with oil bath bearings is a much better option. But even though it is rated for around 1000lbs, the suspension can hammer the boat on bad pavement or rough mountain roads.

So, back to the topic -- do we have any good designs for home-built trailers with quality suspensions and running gear? Or will the best option always be to pick up a used Trailex or (if really lucky) an old Holsclaw?

[BBSebens]

Suspension is the biggest problem in the small wooden boat trailer world. Everything else is relatively easy to work around. The EZ Loader that mine sits on is good for 800#, but my boat and gear might be 300. Thus it bounces and jounces and generally does bad things.

Im going to throw the Airbag idea into the fray. Imagine a set of pickup "helper springs" between the frame and a swing arm of some kind. Wheels mounted to the arm. The Airbags are filled through a simple tire valve, pressurize to your load. I imagine that shocks would also be needed to minimize bouncing.

But how will the hardware on the bags, that obviously isn't marine grade, hold up in the salt water I like to put my boat in? There's the rub in my mind.


I am very interested in the results of this thread.

[Thorne]

Thanks BB, that is one reason why I posted the photos of Todd's Holsclaw suspension. I'm sure that they put all those crossbars and other structural members there for very good reasons -- probably mostly stability / handling.

I know a little about airbag additions in automobile suspensions, but the bags tend to wear & tear fairly rapidly - even quicker if the coil springs rust. Air bags in this context just give lift to the system, not a structural part of the suspension. From the VW TDI Club forum -


http://forums.tdiclub.com/showthread...hlight=air+bag

So I'd be really wary of trying to invent something completely new for boat trailer suspension - again, I want to be responsible and protect my boat and other motorists. My limited experience with the torsion axles was very educational, as was my brief ownership of a utility trailer with no suspension -- SCARY at freeway speeds!

[Dave Wright]

You've made it clear what you want and you've had experience to temper your wants. Unfortunately Holzclaw has been out of business for many years. I salvaged one of the smallest Holzclaw models almost 30 years ago, it was rusting in some blackberry bushes. I paid 10 bucks and got a bill of sale from the deseased owners relatives, but because I didn't have the title, registration was "interesting." It worked well for my 120 pound Laser, but you seldom see these trailers on the west coast anymore. You might be hard pressed to find a decent one.

I'm very happy with my current galvanized Road Runner trailer made in BC Canada and very similar to EZ Loader but less money. I have a 2000 pound capacity model that weighs 440 pounds. They make a 1000 pound capacity model that weighs 260 pounds. These guys are easy to talk to and responsive. If I were you I'd try sending them an E-mail asking if there's anything they could do do "lighten" up and reduce the capacity of their smallest model. I know they've done special requests for some customers. It's worth a try:

http://www.roadrunnerltd.com/intro1.html

[michigangeorge]

I had a Trailex under my Shearwater and it was nice but still did not deliver the ride quality I was hoping for. I wanted something which would provide the cushy, mushy ride of an old Cadillac. Seems to me the only way to get this may be to load any old trailer down to capacity with weights and then put the boat on it. I have my 18' catboat on an old flatbed utility (car hauler?) and she rides as if on air. There must be a way to obtain this with smaller boats.

[mcdenny]

Bayliner sold zillions of boat, motor, trailer packages and lots of the galvanised trailers are around, often with free boats on them. I've got my 450# Arctic Tern on a trailer from a 17' Bayliner (trailer weighs 350#) with one leaf removed from the springs. All up about $500 with new bearings, seals, wheels, tires, lights and wooden bunks. I've towed it a couple of thousand miles so far and rides decently. A brand new galv trailer for the AT was about $1100.

Note old trailers ought to have a "speedi-sleeve" pressed over the journal where the seal lip rides. These are cheap and available for all common seal sizes. The old worn surface will wear out a new seal in no time.

I realize this really doesn't fit Thorne's design brief but is one of the few options for our light (and often precious!) boats.

[rgranger]

I have a copy of Glen-L's pamphlet on building boat trailers. It is a good read.

[Dave Wright]

Bayliner sold zillions of boat, motor, trailer packages ... a 17' Bayliner (trailer weighs 350#) with one leaf removed from the springs. All up about $500 with new bearings, seals, wheels, tires, lights and wooden bunks....

I think many of those trailers carried the "Escort" brand name; they had remarkably few parts and looked very clean and simple.

When I salvaged an extremely rusty Holsclaw trailer I was struck by the higher part count, the higher number of operations going into build each part, the higher number of connections and assembly operations, the higher position in which the boat had to be carried, all for the potentially higher amplitude of load motion. I imagine this is part of why they went out of business. Since I was only carrying a 120 pound Laser I didn't perceive any advantages in reduced shock with the Holsclaw. I mainly liked the 10 dollar purchase price, and this was dampened a bit by the effort getting the trailer servicable. I'd guess the secret is to match the boat weight to the trailer stiffness as you have done with your leaf spring removal.

I'd guess that we might start seeing some pretty small used jet ski trailers on the market which might fill the bill with minimum mods.

[Nicholas Scheuer]

If you go with one of the kit trailers like Dave and Keith suggest, I'd strongly urge a $30 investment in a swivel-wheel tongue jack. Handling a small boat trailer without tongue support is a royal pain, and if you have a folding tongue (nothing wrong with that) a swivel jack wheel might be even more important as you won't have the leverage of a long tongue to grab onto when you want to move it around.

Moby Nick

[Thorne]

All good stuff, folks -- thanks! Don't care if we wander a bit off topic, as for most small wooden boat owners their boat trailers are dear to the heart and essential for boating.

I'll strongly agree with the swing-back rolling jack, and suggest that a good saltwater model kept full of waterproof grease is a decent investment for those of us who routinely launch in salt or brackish waters. I've had the freshwater models seize up after a year even when lubed with waterrpoof bearing grease.

And my EZLoader galvanized trailer may be rated for 1000lbs, but it seems to handle my 350lb dory skiff without bouncing too badly on everything but very bumpy roads. On bad roads I've had it bounce the boat off the bow chock and had to pull over quickly to reposition it. So a trailer with the lovely soft ride of my old Holsclaw would not only be better for the boat, but safer for towing as well.

[Steve Paskey]

For anyone else who might be inclined to try a Harbor Freight trailer, I'll second what Thorne said: they're a piece of crap. I used to own one, and the coupling mechanism broke -- not just popped off, but broke -- while I was driving. I'm thankful that it happened while I was going only 25 mph on a side street.

I don't care if other people have had a good experience with the things -- the quality is suspect, and the potential cost of failure is high. You get what you pay for.

[slidercat]

How to build a jonboat trailer:

http://www.ehow.com/how_6064525_buil...t-trailer.html

It seems to me to be a problem mainly of finding springs that are not too stiff for a light boat.

[amish rob]

The Holsclaw suspension doesn't look too un-doable; it's just a "three-link" rear suspension, like on a NASCAR. I believe the big stock cars all use "five-link", but it's all the same really. The trailing links (one or two per side) hold the axle and allow it to swing on an arc, so the suspension can compress. The third (or fifth) link is the "panhard" bar, or cross link (the crazy dog-legged deal running tranverse on Todd's under-trailer) which is there to keep the wheels in plane, so the axle can only pivot vertically.

Building a trailer with that type of suspension would be a snap for a competent welder. The coil over shocks could come from a junkyard UJM (Universal Japanese Motorcycle), which always seemed to have coil overs Motorcycles should be sprung about right for wooden boat trailers. The axle and wheels may be the sticky part, but everything else is a cinch.

As for the airbag deal, lots and lots of the lowrider crowd have changed from hydraulics to airbags. There are kits for replacing car springs or struts with airbags out there, some complete with a compressor.

If'n I wanted a trailer like you want, Thorne, I'd just start collecting bits and make one. If you can weld, or have a welder friend, you could probably copy that Holsclaw for less that a $G. Maybe you could even begin producing them...?

[Canoeyawl]

More than once I have bought an old 'glass skiff on a trailer for a couple hundred bucks. Towed the skiff straight to the dump and brought my "new" trailer home.

[Chip-skiff]

I've gotten good service from cheap trailers from Northern Tool (I waited 'til they had a sale— less than $200 w/o the tires and rims). They're made in Taiwan rather than the PRC, seem to be good steel with a tough paintjob. One is a boat trailer, for the skiff. The other is a 4x8 folding flatbed that I fitted with a raft rack of chainlink top-rail and Kee-Klamps. With the rack off, I bolt on a flat bed and use stake sides that I built. Besides hauling the boats, I used it to haul tons of gravel, sand, lumber, polycarbonate, concrete, etc. to build a large greenhouse.

Nothing new here, except the fact that cheap trailers aren't all worthless/dangerous.

One possibility for an ultralight trailer would be to find a couple identical mountainbike frames with full suspension, get some schedule 40 alu pipe, and do some welding. There's a cat frame builder, David Nissen, who uses bike fittings and builds really beautiful frames that are favored by Class V whitewater rafters. A trailer could be built on similar lines.



http://www.madcatr.com/

[Ron Williamson]

If your trailer tires are 12" and nearing the end of their lives,consider swapping them for car tires.
Car tires have much softer sidewalls and won't last as long,but will give a much cushier ride.
R

[johngsandusky]

One idea for the storage issue: My melonseed won't fit in the garage/basement on it's trailer. I hoist the boat up using tie down straps to the overhead beams. Then I can push the trailer back under the boat. I do have to unbolt the post to avoid scatching the hull.

[Canoeyawl]

Just a note about car vs trailer tires.
Trailer tires have a shallower tread depth by design. This is to help tracking and to prevent "squirming" or that irritating sway from side to side that can develop on the trailer. . In a lot of respects it can be likened to the "death roll" when running down wind.

[Thorne]

Interesting stuff - thanks again!

Johngs - have you considered making the tongue removable? As I mentioned in an earlier post, you can cut the backbone/tongue, fit a 3'-4' sleeve over it bolted to one end, and use strong SS bolts and locking/double nuts to attach the other end tor trailering. Depending on how much melonseed hangs over the back of the trailer, that might let you put it in the garage without the hoisting system.

[Breakaway]

fit a 3'-4' sleeve over it bolted to one end, and use strong SS bolts and locking/double nuts to attach the other end tor trailering

Thorne,

I havent done this, but if I was going to, I might consider using pins and clips, liek a hitch pin, rather than bolts, for quicker disassembly. Any reason this would be a bad idea?

Kevin

Kevi

[Dave Wright]

Thorne, in addition to your original requirements you've further clarified that:
1.You do high milage trailering on rough roads.
2. You've already done the Harbor Freight / Northern tool cheapy trailer route at least twice, and you've extensively rebuilt these trailers and note that they are not for you.
3. You've owned an old style Holsclaw trailer which you liked, and which you feel provides suitable suspension.
4. You're considering building some sort of trailer if you can find a suitable design.
5. You own an EZ Loader galvanized trailer which you like, but you want additional shock absorbtion for a light boat.

Seems to me any commercial trailer, or trailer parts that you buy or build up, are going in be in the 1000 pound load category or heavier. Essentially you have said you need that sort of rolling stock for durability and reliability, and it's too expensive to get any sort of "quality" trailer with a "lighter" rating.

Seems to me that you probably recognize that building a "Holsclaw" style trailer from scratch involves a lot of additional details and work compared to a leaf spring style trailer.

Why not try taking your 1000 pound capacity EZ Loader trailer and adding foam planks to the bunks and see if this provides the cushioning you want for your lightest boat? The foam I was thinking about is Dow Ethafoam. You might have seen this in the past on some aluminum canoes, I forget the canoe brand, but they came with a big thick black plank of Ethafoam along the gunnels, and I recall that it was tough as heck and seemed to hold up very well under abuse. I'm thinking of the densest Ethafoam variety, Ethafoam 900 at 9.5 pounds per cubic foot:

http://www.qualityfoam.com/docs/ethafoam-900.pdf

Perhaps the lesser densities would work too, I'm just not sure of their durability. I've never tried to buy it, priced it, or looked for it, but it might be worth a try.

If this gives you improvements but is still not the cats's meow you can further experiment with altering the leaf springs on your EZ Loader per mcdenny's post.

Or, you might reflect further on how a modified bunk system or other support system can provide further cushioning on a standard trailer - without being specific and without actually doing the design, I have to think that the two big springs and three shock absorbers on the old Holsclaw trailer might switch on some mental light bulbs for a not too complex bunk suspension arrangement. Providing additional suspension at the bunks might appeal to you in that it would not alter or compromise the road worthiness of the conventional EZ Loader or other trailer. Or, require you to feel resposible for the road worthiness of an all up trailer design that you do from scratch

[Ben Fuller]

There are some bunk things I do to provide boat support. I pull the rollers and put in a padded wide full length keel support, then am real careful adusting the side bunks so that they stabilize but don't significantly support the boat. Then I cinch the boat down pretty hard; becoming one with the trailer and no point loading is the goal. I also take anything out of the boat which is hard... including oarlocks, rudders, loose seats, dagger boards etc. That goes in the back of the car, truck, or on the second deck which I can rig. Seems to have worked pretty well with the ducker at about 150 lbs. After 30 plus years she leaks a little but its not because of the trailer. I think the trailer I have is rated under 1000 lbs, but I would have to go look. It is a conventional leaf spring affair, which has a break back frame, real handy for shallow launches. I bought the smallest galvanized I could find many years ago and special ordered it with an extended tongue.

If you decide to respring your trailer, lightening the springing, a custom trailer fabricator could figure out what would be needed.

[Todd Bradshaw]

Unless it only gets temporary, short-term compression, ethafoam probably isn't a great choice. If you leave it weighted down for extended periods it tends to go flat and stay that way. It's great stuff for certain applications, but not for those where it's continually being squashed by something sitting on it.

[Ben Fuller]

Ethafoam is a bit rigid. I like that tough closed cell foam used in back packing applications but it is not very thick.

[Dave Wright]

Unless it only gets temporary, short-term compression, ethafoam probably isn't a great choice. If you leave it weighted down for extended periods it tends to go flat and stay that way. It's great stuff for certain applications, but not for those where it's continually being squashed by something sitting on it.

See page two of the Dow spec I provided for the foam I mentioned, Ethafoam 900. Note compressibility of Ethafoam 900, where average loadings are given for 10%, 25%, and 50% deflection. I think the specified boat weight by Thorne was 350 to 550 pounds. I assume his bunks would be at least 5 feet long by 4 inches wide and he'd use 2" thick foam. His worst loading for these two bunks is roughly one psi worst case.

Per the spec, 84 psi gives 10% deflection. You have to guess what one psi loading gives.

Note too, compressive creep per the spec.: Less than 10% at 20 psi for 1000 hours at 73 degrees F. Again, you have to guess what one psi loading gives.

But, as I said, it's just something to try in lieu of building another trailer. It may or may not be satisfactory. I would hope that one could get enough foam for two bunks for around $30 or $40.

[johngsandusky]

Interesting stuff - thanks again!

Johngs - have you considered making the tongue removable? As I mentioned in an earlier post, you can cut the backbone/tongue, fit a 3'-4' sleeve over it bolted to one end, and use strong SS bolts and locking/double nuts to attach the other end tor trailering. Depending on how much melonseed hangs over the back of the trailer, that might let you put it in the garage without the hoisting system.

Thanks Thorne, My method works well, no cutting or additional parts. I think the boat hull weighs less than 150lbs, so it hoists easily.

[Thorne]

I've repaired boats that were dropped in storage, so I'm a bit sensitive to that issue. And of course hoisting my 350lb dory is a much larger project, so I don't do it unless absolutely necessary...

[David G]

Twin,

I'm perpetually on the same quest. My two little boats are only 150# & 70#. I was hoping your inquiry would unearth the perfect solution. King Trailers - up here in Ore-Gone - make an all-galvy, oil-bath trailer that has 12" tires, & is rated for 700#. They are willing to fit it with an extended tongue, or one can use the usual growth tricks on your own.

http://www.kingtrailers.com/trailers...l?catId=158082

[frank pedersen]

Dinghy trailers in the UK typically use a rubber torsion suspension system that is tuned to lower weight boats. They appear very similar to what is used in the expensive Trailex aluminum trailers. IMO it might be possible to buy just the axel/suspension system in the UK (at a reasonable price) and find the rest of the materials to complete it here in the US. That is my plan for a Shellback/rowing dinghy trailer.

Frank

[John Meachen]

This is the sort of thing Frank refers to http://www.indespension.co.uk/b2c/ap...N35=006&slnk=1 .I suspect the cost of shiping might be a bit steep.

[keyhavenpotterer]

John Beatty was unable to buy an off the shelf trailer in Fiji, so he designed and built one, buying the road wheels, suspension units and ball-hitch from the UK. He kindly wrote upthe build and supplied the drawings for the design which was for a Welsford Truant. The files are posted on the Welsford Yahoo Group so any one can join the group, many probably are members already, and download the files.

http://groups.yahoo.com/group/jwbuil...0for%20Truant/

I think it's the first time I have seen a design available for home build of a trailer trolley combination.

Possibly John might allow the files to be loaded on Google Docs so everyone can see them.

[Dave Wright]

.....Not willing to consider torsion axles, or suspension systems rated for 1000+lbs, both of which seem to be the only lightweight ones readily available from Northern Tool and other major retailers....

Does this rule out torsion axles all together, or does it just rule out torsion axles rated over 1000 lbs?

[Rob Hazard]

An aside: My boat, a Coquina, overhangs the end of its trailer by enough that the trailer's tail lights are hard to see, so I've been thinking about copying Thorne's rig and making a stern bracket to carry the lights and license plate up where they are visible. This would also allow me to remove the lights and store them in the car before launching the boat, thereby keeping them dry. Has anyone (besides Thorne) done this before? And is it even vaguely legal?

[David G]

Rob,

Perfectly legal in the states I travel in.

I have a similar light bar, and have used it for several boats

[Thorne]

The only non-legal bit of using a light bar is the side-lights part. I don't worry about the yellow side-lights not being part of the light bar setup, as the vastly greater visiblilty of the light bar (I have various reflectors and reflector tape plus the lights on mine) seems more important than any side lighting -- particularly when the hull is painted white.

I suppose there is some very slight legal risk in the light bar without the side lights, but suspect it would be a very small part of any overall legal fallout from an accident. Worth it in my book!