Islander Trailer Setup

[Hookup1]

Do you have any profile shots if your Islander on the trailer?
I've been having some stability issues (sway) despite having everything set up correctly - level trailer, tongue weight, wheel alignment, etc. My truck is an 18 f150 max tow - good for 13k lbs.
My 248 was set up the same way and towed straight and stable. This boat is the same width but 2k lbs heavier and I can't figure out what is causing it.

Thanks. I'm curious to see where the axles are with respect to the hull.

 

[family affair]

Wow. Your axles are way further ahead than mine and I already moved mine up at least 10". My tongue weight is arguable too heavy by some standards, but I'm dead on for what the trailer manufacturer recommends. The trailer is way more stable than when I started, but sways a little more than I think it should. Considering your axle placement and stability, I might try moving mine up another 2". Another thought of mine was to move them an inch further apart. Triaxles tend to be more stable due to the spread of the axles. I don't see why the same can't be done with a tandem as long as there is no interference with the fenders.

 

[SkunkBoat]

Do you have any profile shots if your Islander on the trailer?
I've been having some stability issues (sway) despite having everything set up correctly - level trailer, tongue weight, wheel alignment, etc. My truck is an 18 f150 max tow - good for 13k lbs.
My 248 was set up the same way and towed straight and stable. This boat is the same width but 2k lbs heavier and I can't figure out what is causing it.

Thanks. I'm curious to see where the axles are with respect to the hull.

View attachment 24250 View attachment 24252 View attachment 24251

my gut reaction is there is a lot of boat hanging off the back

 

[family affair]

my gut reaction is there is a lot of boat hanging off the back

Right, but he is the one who tows to the keys every year with rock solid stability. Appearance doesn't matter; only the numbers and results.

 

[Ky Grady]

Hmmm,,, sway could be because of the overhang of boat and twins off the rear of the bunks together with towing with a single axle, short bed, F150. If trailer was correct length, the trailer axles would also be located further back.

 

[family affair]

Appreciate the feedback, but you are reading an oddly written post wrong. Hookup is having no sway issues, but I am, despite having the trailer set up to Loadrites specs. His truck is an 07 rated for 9k lbs. Mine is the 18 set up for 13k.
I asked for photos to see how his boat was positioned to get such great stability. I agree that it looks a little off, but his results are better than mine.

 

[Ky Grady]

Yup,,,definitely reads wrong. The pic of your setup looks like it would be the better ride. Trailer fits the boat better.

 

[family affair]

Yup,,,definitely reads wrong. The pic of your setup looks like it would be the better ride. Trailer fits the boat better.

View attachment 24257

I know! You'd think I'd have no issues, but the trailer is pretty easily unsettled by semi's driving alongside or crosswind. My guess is this trailer is simply more sensitive because of how it is spec'd. Trailer gross rating is 10k but uses 6 k axles. Tires are the limiting factor.
Considering it is way better than where I started, I think I'm on the right track, but need to fiddle a little more to get it 100% ironed out.

 

[DennisG01]

Hookup, sway is most commonly caused by too little tongue weight. It looks as if you that might be the case, but go ahead and physically measure it to be sure. Shoot for about 7% of total weight. Another factor could be underinflated tires and/or tires that aren't of the proper rating for the weight. If your suspension uses any bushings, check the condition of those, as well.

 

[Ky Grady]

What tires are you running on the trailer?
What's PSI setting for them?

 

[family affair]

Hookup, sway is most commonly caused by too little tongue weight. It looks as if you that might be the case, but go ahead and physically measure it to be sure. Shoot for about 7% of total weight. Another factor could be underinflated tires and/or tires that aren't of the proper rating for the weight. If your suspension uses any bushings, check the condition of those, as well.

Dennis, Hookup has no issues, it's me. His initial post was actually a PM I wrote. He couldn't post photos in the chat so he made the thread.

KY, I'll have to check the tires, but I think they run at 80 psi. I max the pressure out. As for capacity of the tires - total is about 10.4k lbs. If I went up a load range I'd have a gross capability of about 12k. Apparently the only difference between the 10k and 12k gross Loadrites is the tires. Everything else is identical.

 

[DennisG01]

Family... Oh, OK, NOW I understand what you meant by a "confusing thread". So... the picture in post #2 is your setup?

 

[family affair]

Family... Oh, OK, NOW I understand what you meant by a "confusing thread". So... the picture in post #2 is your setup?

Right.

 

[DennisG01]

Alright, I would still go back to some of the points I made above. But it does "look" like your axles are decently placed. IF anything, DO NOT move them forward like you are talking about. Measure the tongue weight, though, to be sure - and then possibly move the backwards.

10K gross probably equals "somewhere" around 8,500lbs carrying capacity. How close are you to that number? LR's are decent trailers, but they're not known for being "over built" so you really have to be careful if you're at/near max load capacity.

What size are the tires? 80psi sounds like 10-ply (E-rated), but they look on the small size - maybe it's just the picture. But I would expect to see 15" wheels on a 10K trailer. I had a 10K gross trailer that I trailered my 28' Sea Ray Sundancer (I was right at the capacity) with and it was rock solid at 70MPH and no issues with sway or when a truck passed me... or me passing a truck! That was a Shoreland'r and it used 15" wheels.

Another thought, and just throwing this out there in case you get to this point, is that you might benefit from a WD hitch setup... which is ideally used with an EOH braking system.

 

[family affair]

Tongue weight is 600 lbs.
Trailer has a carrying capacity of 8400 lbs. Typically the boat is around 7500 lbs. I have no reason to fill both tanks and water. Even if I did, I'd be around 8200 FWIW.
I think you are right about the tires. I likely have load range D, because I know I could go to E for additional capacity. Again, minus the beam length and load range E tires, this is the same trailer as the LR 10k capacity trailer. I've got plenty of capacity everywhere.
The engineering of this trailer will not allow for a WD set-up, not to mention my tolerance for the PIA it would be!

 

[DennisG01]

OK, try this first... move the winch stand forward about 6" and see how that works. I wouldn't be surprised if the rig is heavier than you think/are calculating... they usually are! It's a heck of a lot easier and quicker than moving the axles. If that helps, you put it back and move the axles. If it's exactly the same, then look at tires.

If your max PSI is 80, I'm pretty sure those are already E-rated... but they could be smaller diameter than what would be "ideal", anyways.

 

[family affair]

That's my plan. Hookup's photos were the sanity check.
I've set up a number of trailers with excellent results, but this one has been a challenge to say the least! I bet I have over 20 hours setting bunks, moving winch stands, moving axles, fenders, etc. The good thing is the changes are making improvements, but it still isn't where I think it should be.
Amazingly there isn't a single article or video out there explaining the physics of trailer sway with all the numbers. Everything is anecdotal. If I could get some numbers, I wouldn't have to keep guessing!

 

[DennisG01]

Yeah, it can be a bit of a PIA sometimes. Hookup's is a little deceiving because of the way the hull/stern is. But VERY generally speaking, it seems like Grady's like to have the axle/axles centered around the "dip" in the gunwale.

I think it's hard to come up with specific rules for how to fit a boat to trailer since there are so many different combinations and variables. However, manufacturers can sometimes provide this information for their own boats. Give Grady a call and ask for the specs to help with fitting a trailer. If I remember, it has things like center of gravity, and such.

I think once you increase the tongue weight a bit more that you'll be good, though.

 

[ROBERTH]

From what I can tell, the boat is way aft on the trailer from normal. I would do as mentioned first, move the winch stand forward and then test it. I don't think tires on a dual axle full of air can make or break a sway issue. It should be a weight/balance issue.
My first RoadKing trailer was 8600K and when ordering my new one, is a 12K. Same exact setup, but dealer thought the boat needed to be moved forward on the new trailer. However, I ended up having to move mine back as the tongue weight was way too heavy. However, further forward was no issue towing, just way heavy on the truck and heavy on the forward axle, more than the 2nd axle. Now I have it balanced by moving back, had to redrill the bunks and move to support the transom and no issues. But the tongue weight is still very heavy. I tow over 70mph at times and no sway or issues and is very stable so far when windy as well.

 

[Hookup1]

Sorry about the confusion. Those 3 pictures at the start of this post are my boat. I couldn't figure out how to put a photo in a PM so I started a new thread.



My trailer is a Sea Lion S-28T-8200BB. Purchased December of 2013. Tires upgraded. I run LOADSTAR ST225/75R-15" RADIAL Tire, Load Range E at 80 psi. Previous trailer was a Venture VRT7400 tri-axel. Did not like the Venture trailer - I prefer the 2-axel trailer with better tires.

From another post I wrote RE: Towing Grady with Jeep
I tow my 268 Islander from Cape May NJ to Islamorada and back every winter for the last 14 years. Same truck - 2007 Ford F150 with 9,000 lb towing capacity. Boat is 4,700 lbs, Yamaha F150's - 470 lbs each, trailer estimated 1,000 lbs, fuel usually light but lets say 75 gallons at 7 lbs = 525 lbs. Total 7,165 and with gear and household stuff it's close to 9,000 lbs. 24 hours seat time, 1,300 miles, 9 mpg around 60 mph +/- 5 MPH, locked out of overdrive. A little slow getting up to speed but easy drive. You can almost forget the boat is back there.

Trailer specs:

Dimensions​

Overall Length 30'-8"
Length Boat: 26-28
Overall Width 101
Frame Type 5x3
Transom Height to Bow eye, Min: 21'-6" | Max: 26'-6"

Capacities​

Cargo Capacity 8200 lbs

Wheels & Tires​

Tires, Rear Specification Minimum: ST225/75D15D

Chassis​

Axle Count Tandem Torsion