Fishtailing defeated!

[tdubb]

Trailered my recently purchased Mac 26d some 700 miles last weekend, from the Sierra Nevada to Long Beach for an inaugural ocean sail to Catalina.

The fishtailing on the way there was so frightening that we pulled over three separate times to move gear around in the boat, dump water weight, move gear into the Jeep, and anything else we could think of short of installing a sway bar. Fact is, nobody wanted to navigate downtown LA with a trailer that was experiencing unpredictable and violent fits of fishtailing.

150 miles from home, there was only one other thing that could be done, which I now realize MUST be done when trailering this boat more than 10 miles--remove the engine. The guy who sold me the boat never said anything about this, but after taking it off and manhandling it into the cabin, the boat trailered like a dream. Turns out a 150+ weight hanging off one side of the boat doesn't help with trailer stability, go figure...

This should have been obvious to me and probably is obvious to more experienced trailer sailors, but to those people who have these problems and still have an outboard hanging off the back, I can promise it makes an unmistakable, and in this case a voyage-preserving difference. It was a good thing, because the lobsters were delicious and the sailing was great fun.

[LOUIS B HOLUB]

...when I trailered my prev. boat, a 26-S (basically the same as your 26-D), we never had a trailering issue even with the engine hanging on back. The 26-S trailered much better than my "X".
We had an 8 hp Merc. on the Mac-S along with fuel tanks in the Laz., and the weight seemed to be no problem at all.

If you jack your trailer up, and spin the wheels, listen for grinding sounds. Its one way to check wheel bearings. Of course, it's better to pull the wheels, and visually check them.

[Trouts Dream]

Fishtailing is directly related to tongue weight (or more specifically , lack of)

I have a 90 HP Yammy on the back of my X and I make sure of the following before hauling.
1. No fuel in the tanks. I carry a siphon hose and transfer fuel from my tanks into my Envoy before heading out. You'd be surprised what 2 full tanks weigh.
2. Move everything possible onto the front berth including tool bags etc that are normally stored in the aft berth (just temporary for towing)
3.Ensure the "Mac Bump" has the boat all the way forward. Even a 2" gap makes a huge difference in how the boat is balanced over the axles.

What a difference it can make. Should be no reason to remove the engine.

[kmclemore]

Something is desperately wrong with your trailer/boat configuration, because a stock, unladen Mac with a normal 50hp motor should not fishtail... the boat is balanced on the trailer such that it has about 350 lbs. of weight on the tongue and that's 10% of the total weight, so it will almost certainly not fishtail.

Rule of thumb for any trailer is to place at least 10% of the trailers overall weight on the tongue, and this will virtually eliminate fishtailing. If you've loaded a bunch of junk in the aft of the boat, well, that reduces your tongue weight. Similarly, if it's not a stock trailer or somehow the boat is not fully up against the trailer's original v-block at the bow (i.e. it has shifted back on the trailer), or if the axle has been moved forward, this will also change the balance and reduce the tongue weight.

Have a search on this forum - Catigale earlier demonstrated an easy method for measuring tongue weight with a bathroom scale and a few boards... there's even photos, if I recall.

[grady]

A lot of owners end up putting dual axles or moving the single axle back. I moved my single axle back 13" and it made a big difference. before anything above 50mph it could fishtail and above 55 it started feeling unsafe. after the axle was moved i have been up to 80mph with no issues at all. If you load your boat up and know the total weight and tong weight it is really easy to calculate how far to move your axle to achieve the 10% tong weight.

[tdubb]

thanks for the replies, i am going to check those bearings.

[ronacarme]

We avoid fishtailing in trailing our 2001 X as follows...
1. enuf tongue weight, per posts above
2.trailer tires at least at max inflation listed on sidewalls (50 psi on ours)
3.rear van tires at near max inflation listed on the sidewalls ( at least 40 psi on ours), not at the low psi suggested by the vehicle maker for a soft ride.......the hard tires minimize sidewall flex and hence lateral sway of van rear end, trailer tongue and trailer axle
4.for longer trips,we lighten the load on the trailer by shifting gear from boatcabin to van, and shift cargo in van forward to lighten the load on the van rear axle to allow enuf tongue weight per 1. above.
We were sway free for 3200 mile trip from MI to Flamingo FL and back a few years ago. Our motor stays on the transom.
Ron

[Catigale]

3.rear van tires at near max inflation listed on the sidewalls ( at least 40 psi on ours), not at the low psi suggested by the vehicle maker for a soft ride.......the hard tires minimize sidewall flex and hence lateral sway of van rear end, trailer tongue and trailer axle

Ron - I took my van tire pressures up to the max sidewall this season and found it does trailer much better. I use the sidewall maximum pressure of 45 psi on all four, and 50 psi on the trailer tires.

[tdubb]

Thought I would add a quick update to this discussion--I did check and re-pack my wheel bearings, they were in fine shape. I had always known the tires that came with the trailer were two different brands, but during this process I noticed that the load ratings were different (one was a B and one a D) so i bought two new tires. During my test drive, with the boat practically empty it was still fishtailing pretty bad--no better or worse than before. I then took some of the above advice and emptied everything except the engine from the aft of the boat, put it all in the V berth, put all my other gear up there as well, until I had a reasonable amount of tongue weight, probably 100-150 pds. Problem solved--I'm convinced it was all about weight distribution the whole time. thanks for the replies and advice.

[Phil M]

3.rear van tires at near max inflation listed on the sidewalls ( at least 40 psi on ours), not at the low psi suggested by the vehicle maker for a soft ride.......the hard tires minimize sidewall flex and hence lateral sway of van rear end, trailer tongue and trailer axle

Ron - I took my van tire pressures up to the max sidewall this season and found it does trailer much better. I use the sidewall maximum pressure of 45 psi on all four, and 50 psi on the trailer tires.

That is great tip. I thought the 32 lbs of pressure for my truck tires, as listed on the door and in the owner's manual, were for traction purposes. I did not know it was for a soft ride. The pressure will go up to the maximum 44 lbs asap.

Phil M

[SkiDeep2001]

Just a word of caution; if you are going to keep max pressure in your tires as I do and travel on gravel roads, be prepared for more frequent blowouts After experiencing numerous blowouts, on new tires, when traveling the back roads in BC, a local repair shop suggested I lower the pressure if doing a lot of travel on gravel roads. My FREQUENT blowouts, dropped to zero. Be sure and re-inflate to proper pressure when you get back on the hardtop. Carry a tire pump, in certain areas it may be a a few miles before you reach a filling station. Rob

[Capt Capsize]

My brother 26d had a similar problem. The factory trailer setup was balanced for a boat with no motor. He moved the axle back about 10 inches and completely solved the problem.

The event which precipitated the trailer mod was the result of hitting a large deep pot hole. This shattered the leaf springs blew out one tire and nearly tore the axle completely off the trailer. Having a spare axle from my 26X's 6000lb axle upgrade allowed him to replace the axle on a carrier an mount it with proper tongue weight.

If you don't go with a tandem axle, just move it back some. It involves a bit of grinding and welding if you DIY. It is worth it for the quicker set up time and the back pain eliminated from lugging the motor around.

[Harry van der Meer]

This spring I installed a dual axel on my steel X-trailer and replaced the box-tube with a 1 foot longer, heavier gauge one. Have trailered now to Rockland, ME and Burlington, VT using my GMC Yukon. Have had speeds up to 75 mph. Towing is a dream now, very stable and comfortable, even when semi's pass. I am not worried anymore how the trailer is loaded, including Suzie 2.5 dinghy motor on a bracket on the back, next to the Honda, 12 gal of gas in the back, and 15 gal of water over the axels. Highly recommended mod.

[kelseydo]

A long single axle trailer will fishtail with a light tow rig - period. If you can't/won't add another axle to the trailer, then the changes must be made to the tow rig. I just got back from a week at Lake Powell (400 mi each way) and had now sway problems. Single axle stock trailer, heavily loaded boat, 65 - 70 mph, and 3/4 ton tow rig with air springs. Fixes are in order are:
Slow down.
Get a stiffer tow rig.
Add independent air springs and run enough pressure to re-level rig and trailer when fully loaded.
Move up one tire rating C to D or D to E and run at max pressure.
Run at max tongue weight for your rig and hitch.
Equalizers and anti sway devices help some, but not worth the money.
I know this from ten plus years of experience towing my 26 foot single axle 1957 Airstream Overlander where adding an axle is not an option. I love my Airsteam and hope to be buried in it.

When towing remember to whoa must always equal to go,
Dan