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Looking for pros and cons on single or tandem axles for a 21 ft aluminum boat that weighs in at about 3,000 with motor and gear. I've had both with other boats and like the ease of handling on the single. Appreciate the feedback.
Two axles are always better. You can get away with less tongue weight as the tandem axle trailers are not as prone to sway. In general the more tires you have on the trailer the better it tracks and tows. You will also find that is reverse, the trailer does not swing around as much as a single axle.
For a 21 foot boat you can have each axle large enough to support the entire load. The big advantage here is that if you lose a tire - it is not a problem. You can keep rolling on three tires. For that matter, even if you lose both tires on one axle you can keep rolling as the remaining axle can still safely handle the load. And tires are not all that can go - there are bearings and spindles and all kinds of fun things that can go bad on a trailer.
I have a single axle now, but the axle is up for replacement soon and I am considering going tandem. I plan to get two axles that can each handle the full load. One axle can totally fail and I will be able to keep moving - unless the failure is extra super bad.
The issue I am looking at now is converting my single to a tandem, or trading the current trailer in for a new tandem. I have a cat so I can not just use any trailer - it has to be set up for my boat. So the bunks and cross beams I have on the trailer have to be moved to the new one. Or I just remove the old single axle, bolt on two more, and then bolt on some new fenders.
Choices choices......
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1999 20 foot Seagull power cat
Single 135 Optimax outboard
If the weight of the boat and trailer is 3,000 pounds, and assuming a typical single axle trailer weighs 750 pounds, that total weight will exceed the maximumcapacity of a single axle trailer. Maximum single axle trailer capacity typically is 3,500 pounds. Looks like you don't have a choice and must have a tandam trailer.
Dual axle tows much smoother and is actually easier to line up and back down a ramp, as it does not wander as much as a single axle. Probably the only reason to get a single would be if you had very retricted space and tight turns to worry about, like maybe doglegging into a garage or some similar situation.
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2009 NauticStar 2200 Bay Tournament Edition with 175 hp Suzuki 4-stroke
I'm in a similiar situation except my reason for a single axle trailer is weight.
My truck can only tow 3,500lbs and an average tandem trailer weighs excess of1,000lbs so that doesnt leave much boat.
I have been looking at the Sea Hunt 207 which comes in weighing 2,050. Add engine (466lbs), gas (65 gals x 7lbs= 455lbs) and trailer (600lbs for a single) I am right at my max.
Grant it, I am only towing the boat less than 1/4 of a mile each time and the longest trip will be when I pick the boat up (roughly 60 miles) so I am not too concerned about being at my max but I dont really have a choice but to go with a single.
catchbigtuna - 2/9/2009 12:44 PMI'm in a similiar situation except my reason for a single axle trailer is weight. My truck can only tow 3,500lbs and an average tandem trailer weighs excess of1,000lbs so that doesnt leave much boat. I have been looking at the Sea Hunt 207 which comes in weighing 2,050. Add engine (466lbs), gas (65 gals x 7lbs= 455lbs) and trailer (600lbs for a single) I am right at my max. Grant it, I am only towing the boat less than 1/4 of a mile each time and the longest trip will be when I pick the boat up (roughly 60 miles) so I am not too concerned about being at my max but I dont really have a choice but to go with a single.
So why can't you just add another axle to your single axle trailer? An axle does not weigh that much. This is one of the options I am looking at for myself. Keep my existing trailer, and add two torsion axles to it (the one it has now will need to be replaced soon).
You can also have a transmission shop install a transmission cooler. They can probably also put in an engine oil cooler. If you are towing close to the maximum, these things should be something you have. I would supersize my transmission cooler, going with one rated for a higher GVW than I ever expect to tow. The higher the better I suppose.
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1999 20 foot Seagull power cat
Single 135 Optimax outboard
Lazy- if a single axle doesnt weigh that much, why on loadrite's webpage the tandem axle's start at 1,000 lbs?
If its just a matter of adding another axle after I purchase the single, I'll do that but something tells me that an axle has a good amount of weight to it.
Probably because they just make the dual axle trailers for larger boats. Maybe the trailer frame itself is larger?
According to the Northern Tool website, the shipping weight for a 3,500 pound torsion axle is 86 pounds, and the shipping weight for a 5,200 pound torsion axle is 157 pounds. The axle length for both is 87.5 inches, which may be short for a boat trailer. So add another what? 30 pounds for another foot of axle length? Just a guess there. Then tires and if you need them, brakes. Still not a whole lot of weight - all things considered.
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1999 20 foot Seagull power cat
Single 135 Optimax outboard
Thanks to everyone for the feedback, it's always good to get input from others. I'm still thinking but am now leaning on the side of saftey and a tandem setup. Thanks again
A tandem is safer, and you are about max'd out for singles anyway. I upgraded last year to a newer tandem Load-Rite, this one has brakes on both axles. Something I never really thought about for pulling my 22' bay boat, but 100% more brakes on the trailer stops better when you need it too. I tow it back'n'forth FL-NJ every year, I've needed all the brakes I can muster a couple times.
BTW, if going Load-Rite, be absolutely certain to get the stainless hardware package if using in salt. That was the only issue I had with my 1st Load-Rite (2004 aluminum 5500lb) and the main reason I upgraded. No issues with the 08...
This is my 04 back in 08 when I sold it.... I decided against replacing the hardware and selling it.. Yes it was rinsed after each use (but did live 50' from salt water)..
Is it a big deal to add a 2nd axle to a single axle trailer? How much trouble is it to move the single axle forward or back to make room for the 2nd axle, and then align all 4 wheels to be certain they are rolling in a staight line?
Single or Tandem axle trailer ??
