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

[BBSebens]

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

Isn't one possible solution to a light boat on a heavily rated trailer to load the trailer? For example, I have a trailer rated at a thousand pounds and my boat probably weighs about 160 pounds. I disrecall who, but on a thread once a Washington boat builder said he solves this problem by putting weighted plywood platforms on supports on the trailer to make the load heavier. He had tried just plywood but the trailer started floating...

One of my brothers mentioned putting steel heavy steel bars on my trailer to bring the load closer to the rating. I would rather have a lighter load myself but I can certainly see the sense in doing this.

Eric Hvalsoe does this. Its not a lot of weight, maybe 100lbs I think, Steel or lead bolted to the frame of the trailer. I seem to recall he uses a fairly light weight flat bed trailer and props the boat up with fenders.


It seems that we are coming to a point: Every trailer is a compromise, much the same as the boats themselves. A light duty trailer is going to be light weight and potentially unstable in cross winds, and a heavy(er) trailer is going to be too stiff for our little boats. And the ideal suspension is more complicated than one of us could manage without some metal fabrication equipment, and the simple suspension doesn't reverse engineer down to our load level very well.

Im starting to like the intermediary cradle idea. It would even make it possible to use one trailer with multiple boats, and ease a launch on a shallow beach or ramp. Might even make storage simpler too, and the cradles probably fit closer together than multiple trailers. plus less tax, wear and tear, lights....

[Thorne]

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

The Brits have small trailers that ride on larger trailers, and I think this is to deal with the big tidal range and/or beach launching. But it is a very expensive and complex solution for the overall issue of most modern trailers being sprung for 4x the average boat weight.

[jerry bark]

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

surplus center (www.surpluscenter.com) offers a coil over shock absorber that is made for go cart suspensions. the support 100 lb per inch of travel. a pair of these, or two if your boat requires, on an axle would provide all the suspension needed. So you would have to build a swing arm axle mounting like those used on the back of many cars. If you are a fabricator type it should not be that hard. you can buy a swinging tongue hinge.

jerry

[dbdotdot]

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

That's an interesting site. I followed the link to the Castle Craft trailer site and noticed the 95 pound Trailex single canoe trailer (unfortunately just 200 pound capacity). So does anyone know the details of Trailex's "unique rubberized steel" suspension that "virtually eliminates road bounce? I'd love to have a 100 pound trailer with a 600 pound capacity.

Dave--

I have this trailer. It a Trailex sh-200. I use it to trail my 17' Adirondack Guideboat and just finished a 1600 mile pull. The trailer works well and there was little bounce. Of course, it does bounce, but not because of the suspension. The trailer weighs less than 100 lbs and my boat 75. No amount of suspension or low tire pressure will prevent it from jumping out of a pothole some. However, the whole thing is so light that it flies around as a single, light unit and there's no mass to strain the boat. I installed keel pads to take the load and the boat seems happy enough. It was much happier on NY roads than I was!

The suspension is a simple, short fiber-reinforced strap the axle rides on. The strap (about 4" long) spans a gap in the trailer bracket and the axle is attached to the strap. There is a little give, but not much. Again, the "suspension" in this trailer is based on a bit of strap give, the tire flex, and the lack of punishing mass of the trailer itself.

The Yakama system is a real suspension for a light boat, ut it is priicey and complex. It looks great, but the Trailex works really well for my needs.

[John Meachen]

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

The Brits have small trailers that ride on larger trailers, and I think this is to deal with the big tidal range and/or beach launching. But it is a very expensive and complex solution for the overall issue of most modern trailers being sprung for 4x the average boat weight.

The main reason for the launching trolley combined with a road trailer is to eliminate the risk of damage to wheel bearings when launching the boat.I have to say that to European eyes the layout of American trailers is a bit strange;there seems to be a lot of trailer ahead of the boat and supports a very long way aft.The excess length can get expensive if you use ferries that charge by length so we tend not to use more length at the bow than we have to and the aft end is no longer than it needs to be because it would dig in when unloading.I would certainly agree that torsion based suspension systems can be of variable quality and I miss the old Flexitors which were replaced by the less sophisticated versions you seem familiar with.

[Lewisboater]

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

You might be able to get the suspension parts (replacement) for these and build your own. This one is rated for 250 lbs.

http://www.discount-trailers.com/small-boat-trailer.htm

and

http://www.discount-trailers.com/fishing_boat_trailers.htm

[Dave Wright]

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

Maybe something in between the Harbor Freight Models and the Trailex is this Northern Tool trailer kit: 610 lbs capacity, 190 lbs shipping weight, 600 bucks including shipping (In contrast the 500 pound Trailex weighs 180 lbs, has 500 lb capacity, and costs $1170 plus $50 shipping)

http://www.northerntool.com/shop/tools/product_200365329_200365329

[Thorne]

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

Interesting suggestion, Dave! I can't find the rating for the leaf springs even in the pdf file/manual, which are often much stiffer than the load rating would indicate. For example I believe the springs on the HF utility trailers are rated for 2000lb, but the trailer load rating (recently revised downward from 1350) is 1090lbs.

[Ben Fuller]

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

What I don't like about the trailex trailers is that it is hard to build in padded full length keel support. Point loading on traditional and lightly built boats is the killer. With full length support and nice long padded bunks that are just set to stabilize but not take significant weight you can cinch the boat down pretty hard so that even if the trailer bounces, the boat goes with it without bouncing on the trailer.

The dolly system has an additional benefit besides the ability to make nice custom bunks and supports: it lets you launch on real shallow beaches where you can't get the trailer in deeply enough. Last year at the Small Reach Regatta we had made an extension to deal with this.

Since I have dollys I think my next trailer might be a flat bed.

To the point of trailer length, for traditional boats you may need to adjust the axle. Most commercial trailers assume that you have an engine and the axle is back further than is desirable for an oar/sail boat, so when you pull the boat forward your tongue load can be too high. I recall 10% as the magic number.

[Thorne]

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

For dories and other boats with flat bottoms, I usually just attach a 2x12 covered with carpet to the backbone of the trailer For trailers like the Trailex you can use blocks to brace the plank.

As for tongue weight, I go with 10-15%, but often have to position the boat further aft on the trailer than the stock supports cover. So I'll extend the 2x12 aft and mount a skeg/keel roller to support that end of the boat.

[Ben Fuller]

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

I use the full length board on all of them. Sometimes you can spring the front up to get better support with rockered boats. To control point loading aft, I get the boat on the trailer then bring the roller up so it just kisses the keel. If the trailer had rollers down the middle a carpeted 2 x 4 fits neatly in those welded on brackets.

If you can move the axle a little then you can have the bow of the boat pretty close to the towing vehicle so you don't have quite such a long load.

[Thorne]

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

I actually don't mind the distance between bow and hitch, as it allows launching on bad ramps and beaches without submerging the car's exhaust in salt water, and gives you room to hop up on the trailer tongue to get out to the winch stand. I'm so used to the basic length of 16' boats on a trailer that my utility trailer with a much shorter tongue and distance from hitch->axle really throws me off when backing up.

[Eric Hvalsoe]

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

Eric Hvalsoe does this. Its not a lot of weight, maybe 100lbs I think, Steel or lead bolted to the frame of the trailer. I seem to recall he uses a fairly light weight flat bed trailer and props the boat up with fenders.


It seems that we are coming to a point: Every trailer is a compromise, much the same as the boats themselves. A light duty trailer is going to be light weight and potentially unstable in cross winds, and a heavy(er) trailer is going to be too stiff for our little boats. And the ideal suspension is more complicated than one of us could manage without some metal fabrication equipment, and the simple suspension doesn't reverse engineer down to our load level very well.

....

Oh I spose I should have been following this thread - the title was about lightweight suspension - which I've not much explored. There are several good reasons 'boat trailers', ie caulkins EZloader etc, are called boat trailers. And this is what I modify for my clients. But the minimum gross rating, at least for a Y frame, will be about #1000. I remove the standard bunks and rollers and build up a lumber platform. That adds a couple hundred pounds. It also adds flotation. So I bolt some ballast towards the rear end of the platform. With some of these trailers you can also move the axle forward to reduce tongue weight - these things are typically set up for outboard powered boats and those irritating ski doos. It is possible to juggle things and end up with a tongue wieght of 60 - 100lbs. The whole package is not particularly lightwieght - this is not a hand dolly. Practice your vehicle/trailer backing up skills. But you do end up with something that launches easily, protects the boat, and is not overly harsh on the road. My boats have been trailered successfully across the country with this rig.

The EZ loaders jumped in price the last couple of years. They are not cheap. But they are good quality with submersible lights, good tires, etc. Would love a new one for myself, I'm using a hand me down with little bitty tires. Beware of the chinese stuff, particularly tires.

[Tom Kremer]

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

That's an interesting site. I followed the link to the Castle Craft trailer site and noticed the 95 pound Trailex single canoe trailer (unfortunately just 200 pound capacity). So does anyone know the details of Trailex's "unique rubberized steel" suspension that "virtually eliminates road bounce? I'd love to have a 100 pound trailer with a 600 pound capacity.

After years of dragging around a rusted thing I built out of the small HF trailer, I finally got one of the Trailex singles. Much of the "suspension" comes from the low PSI that they recommend using in the tires. Fill them to rated capacity and you can dribble the trailer like a basketball but at 12-15 PSI and loaded with my Herreshoff/Gardner 17' it pulls real well. Light is good, especially if you have a compact car.

[Dave Gray]

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

... I remove the standard bunks and rollers and build up a lumber platform. That adds a couple hundred pounds. It also adds flotation. So I bolt some ballast towards the rear end of the platform. With some of these trailers you can also move the axle forward to reduce tongue weight - these things are typically set up for outboard powered boats and those irritating ski doos...

Eric, if you don't mind, could you post a photo of one of your modified trailers?