Trailer Jack Stand Design

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Eidoloneliz23
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Trailer Jack Stand Design

Post by Eidoloneliz23 »

Jack stand design
Jack stand design
Hi James,
My shed is built and I’m finishing up the trailer to haul my boat home. WOOOO HOOOOO!
I have a question about the jackstands.

Is there any way you could measure the screw jackstands on your trailer in this picture?

Currently I have one piece of 2 in. square tubing welded to the trailer frame with the screw jack/pad (with washer and nut) on top of the tubing. The threaded rod is 1 1/4” galvanized.

I Measured my boat in the boat yard and set up the stands to those measurements.
I feel like it’s putting too much threaded rod up in the air, almost the entire 30” of the rear stand rod with approx 6” left in the square tube. (the rear stands have 30” screw jack lengths, the stands forward of the rear stands have 24” threaded portions)

I’d rather have two telescoping pieces of square tubing like you have on your trailer.

In the picture, I can see there is a square collar at the top of the upper telescoping section that looks like it is there to stop it from falling all the way through the lower section when it’s retracted.

Is there anyway you could measure your telescoping stand units for me on your trailer.
and I do understand that it takes a hitch pin with a cotter pin to lock it in place when it’s retracted down and also when it’s in the upper position.

It would be very helpful to have the:

dimensions of the telescoping unit (including the tubing size)

position of the holes drilled

length of the threaded portion of the pad assembly

angle of all of the jackstands

and the distance apart from each stand on the trailer as a double check

My boat is currently on Brownell stands in the boat yard and it looks like they’re at a 15 to 16° angle.


I’m willing to come and quietly wash, scrape, sand or polish stainless as a barter.😳😊

Cheers!!! and thank you

Elizabeth
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

After looking closely at materials, it appears that the piece of square tubing with the collar on it is actually receiver tube. Receiver tube is perfect because it doesn’t have the welded seam and allows tube in tube to slide smoothly.
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Re: Trailer Jack Stand Design

Post by atomvoyager »

The upper telescoping tube diameter is 2" and the lower is 2.5".
The pin hole positions are three for each support spaced between 9-11" apart depending on overall tube lengths.
The screw pad thread length is 24" with 12" sq carpet covered 3/4" plywood pads.
The tube supports are welded to frame 66" apart aft, 64" center, 60" forward.
Below is a sketch of other dimensions and hull support angles that I specified to builder:

1. Tandem 6,000 lb (or 7,000lb) drop axles, both with electric brakes.
2. 12,000 GVWR construction, 7" channel, 2 5/16" ball.
3. 2,000lb plus fixed tongue jack welded to left front (not the lighter swivel type).
4. Lift-off type design with 7 extendable nesting hull support channels and screwpads with 3 pin positions spaced approx 10” apart. Aft supports to have a 4th pin hole 4” from the ends. Dimensions on sketch for supports are measured from top of outside frame.
5. V screwpad at bow on sliding base held by U-bolts with extending riser channel with pins like side supports instead of bolt-tensioning type because those can slip.
6. Removable aft frame section for rudder removal.
7. ST235/80R16 Range E tires or equivalent with spare tire mounted on welded bracket on right forward side.
8. Best available metal primer and black paint.
9. All galvanized fasteners.
10. LED lights with tinned marine wire.
11. Main 7” U-channel frames to continue forward within 8” of tongue for best support.
12. Treated wood for screw pads and bed.
13. Standard lock pins on adjustable hull support tubes (not bolts and nuts).
14. No side keel support boards needed.
15. 2x10 treated bunk board.
16. License plate holder bolted to left fender.
17. Shipping weight to be listed as 1,990 lb.
SailTrailer Sketch 2021.jpg
Eidoloneliz23
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

Thank You so Much James!!!!
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

Thank You so much James!!!!This is so thorough!!

…and the aft removable section is such a great idea. I was just about to weld it on.
I am glad this was caught thanks to your information.
It will be perfect for dropping the rudder while she is on the trailer.
The rudder is rebuilt with new bearing surfaces and shoe, so I hope to not do this again in the near future.

I’ll let you know how it turns out.
For the jackstands right now I’m looking at 2 inch receiver tubing (no interior weld line)for the bottom 1st section(which is actually 2 1/2 inches OD) then 2 inch square 3/16” wall tubing for the second section, with the threaded rod assembly with pad sliding in at the top.

Cheers!!!!

Elizabeth

PS I am good for the barter offer! :D
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Re: Trailer Jack Stand Design

Post by atomvoyager »

I forgot to mention that the 1.25" threaded rod slips into a piece of PVC tube about 8" long that happens to be a tight fit in the 2" steel channel. They just tapped it in with a hammer and it stays at the top of the 2" channel as a bushing. Since I didn't build the trailer I don't know if the builder had to specify seamless tube or a standard welded tube. I doubt he ordered anything but whatever was standard low cost. Welded seams are often close to flat anyway and may not interfere but you'd need to confirm that with the supplier.
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

James, thanks!!

Yes, currently the 2” square tubing section that is welded to the trailer is lined with PVC pipe with the 1.25” threaded rod sitting on top on a washer and nut.

I think the boat that’s on the trailer in the rudder picture at your shop, is a Pearson Triton based on the rudder straps in the image.

Do you haul a 30 foot Alberg on the trailer that was built from the 2021 dimension drawing?

Thanks!

Elizabeth
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Re: Trailer Jack Stand Design

Post by atomvoyager »

Yes I've used this same trailer specs when hauling A30s. The trailer is designed for any boat up to about 31' and 10,500 lbs so the A30 is a good fit. Right now I have my 28' Triton on one and a Cape Dory 27 on the other same size trailer.
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

James,
Thanks…

I am setting up the metal on paper now and getting ready for the torch and grinder. 😳😊

I’m planning to cut off the existing 2 inch tubes lined with PVC (6) hopefully without warping them or melting the PVC pipe insert (insert is 8”)then reuse them as the top tube in the telescoping portion.

Their total lengths currently are:
35.5” forward
34” amidships
40” aft.

Have a 6” inch long 2.5” OD Curt receiver tube section (Amazon) to check the 2” tubing for interference and trueness. I will slide it down the 2 inch tubing to double check it.

I see I’m missing one measurement though.
How long are the nested 2” square tubes that receive the threaded rod?
I am hoping to reuse the salvaged ones cut off the trailer.
Possibly the lower end of the 2 1/2” should be welded in to leave the bottom open so the 2 inch tubes can pass down through them?

Planning to Drill the first 5/8” hitch pin hole down from the top (of 2” tube) at about 25” so the threaded rod doesn’t hammer a pin when trailering empty.
Then holes drilled ~10” either side of the first hole

I have this funny little paranoia even with all my careful measurements that I will arrive with a trailer that doesn’t have jackstands tall enough… “measure twice”.

When I figure out how to resize images, I’ll take some pictures and submit to help other people on this adventure.

Cheers!!! to Sailing

Elizabeth
Last edited by Eidoloneliz23 on Thu Mar 09, 2023 7:13 pm, edited 1 time in total.
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

And P.S. There was an Alberg 30 in front of me in the yard. Our dimensions are almost identical… and It had the outboard well modification. I suspect it’s one that you had done.
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

Threaded portion of jackstands in progress.

Threaded portion with swivel plates are built.
Steel Plates are 10” X 6”
Three-quarter ply pads 12 X 12 inches are cut primed and painted on one side and edges primed thoroughly.
Quarter inch recycled, rubber sheet material cut to fit each pad individually.

Next is to fasten the 6 X 10” plates to the plywood, the painted side going to weather.
Using countersunk 1/4-20 flat head SHCS full thread with Allen head drive, flat washer and 1/4” nylon nuts.

Then glue the rubber sheet material to the bare ply side of the 12 X 12 inch ply pad using Sika 221.
Sika 221 was recommended for rubber products, but there’s no guarantee there won’t be some kind of bleed through from the rubber. I’ll report back…

I’ve contemplated punching a hole where the screw head is, but I’ll just leave it covered with the rubber because I can always puncture it with the Allen wrench or puncture a small hole in if I ever need to re-tighten them. I think the Sika 221 will also help hold the fastener heads tight.

All of my Brownell screw jack stand plywood tops have always rotted it off, so this time I was sure to seal the edges and back of the ply with a good quality Sherwin Williams exterior paint I had around. Then I applied rattle can Rustoleum, semi gloss, black. It can be safely applied after the Sherwin Williams has fully cured, see product label… I allowed a few weeks.

Then key gently with some 80 grit, wipe down and spray with rattle can Rustoleum semi-gloss black.
My entire trailer has been sprayed with Rustoleum thinned with Acetone over bare metal primer, so this works out for me for maintenance. Reasonably priced long lasting.
Have used Rustoleum on steel cradles with very good results.

Cheers!!

Elizabeth


I’ll post a picture later when they’re all finished.
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

And yep, the washer is on the wrong side so I won’t lose them 😊
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Re: Trailer Jack Stand Design

Post by atomvoyager »

The aft two 2" square tubes are about 30" overall and all the others about 28". The 2.5" tubes are open at bottom. Fully retracted with pins out, the inner tubes sit up to about 2" below the bottoms of the 2.5" tubes and at times you may need them fully down to clear the boat on the travel lift because they may not be able to raise the boat high enough to allow you to insert the screw pads after the boat is above the trailer. I don't want the 2" tubes to be too long because if hauling a smaller boat one day with tubes fully retracted I want them to still have ample ground clearance.

Unless it's a short distance I always remove the screw pads from the trailer when towing empty although I doubt them bouncing on the pins would cause any problem.

Handle pins welded on the nuts are handy but are a snag hazard when moving around and working under boat so I use a pipe wrench instead. You could also injure yourself when working under them and then standing up.

Not sure how your total tube length compares to the measurements on my sketch of height of tubes above top of trailer frame. You don't want them too high for a small boat. The lengths I use are optimized for a boat with 4.5' draft and useable up to 5'. I would have an angle grinder and drill on hand so you can modify the tube lengths quickly if you find them too long when the boat is still on the travel lift.

I've done 5 outboard wells in A30s. I don't recall your location but there are many A30s around whose owners used my free online instructions to build their own outboard well. Several have purchased full size paper patterns from me to aid in construction.
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

James Thanks!

I have all the information needed now to be comfortable with the remainder of this project.
Most of the welding is being done by a seasoned certified welder, that knows the ins and outs.
Maybe I can learn how to weld decently before this is over? I’m trying my hand at the fenders and fender mounts and practicing welding on scrap stuff. If the fenders fall off, it won’t be a big deal. 😊

Thanks for the tips! and the guidance, it was much needed.

annnnd yes, I plan to take a grinder, a Sawzall with a Remington blade just in case for when the boat is loaded. I’ve got a 2000 pound trailer tongue scale to measure tongue weight too.

I hope you have a great day!
Know you’re totally appreciated in this community.


Pics to come..

Cheers to Sailing!

Elizabeth
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

Hello James,
I’m busy cutting the exsiting jack stand tubes off the trailer!!! making a lot of progress.
The 2.5” steel will arrive in about a week or two and will start welding them on then. YAY!!

Yes, I have one more question. 🙃
The measurement for the 2.5” tube supports that are welded to the frame are:
66” apart aft
64” apart amidships
60” apart forward
where is that measurement taken from?

I want to double check and make sure I know where this measurement was taken from.
I understand I am measuring from one point then across the Trailer to another point, with the proper angle and length of the 2.5” base tubing.
Is it from the top of the tube or at the point it was welded to the frame or at the top of the trailer 7” frame?.

Thanks,

Elizabeth


By the way, the Alberg 30 that had your converted outboard well was in a boat yard on the Saint Johns River in Florida. She has since been sold, last month and I’m not quite sure where she’s headed.
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Re: Trailer Jack Stand Design

Post by atomvoyager »

The distance between the square tubes was measured from the base at the top of the trailer frame. The distance apart is not really important as long as you place them as far apart as possible. Hopefully that will make them not less than the dimensions given. Ideally the trailer frame would be even wider and the bases a few inches further apart for our size boats to have best support. Since we can't get that then we just want them as far apart as possible and not angled in too far so that they don't give good support to the hull to resist side loads on the road.
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

Thanks! Got it!!
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

Hi James,

Happy Summer!!

Well, the shed is completed, my mast is unstepped and I’ve nearly completed the trailer.
I’ve begun setting up the drill press to drill the jackstands…lots of holes and lots of cutting oil in my future. :mrgreen:

I’m getting sweaty brains around where the first hole should be drilled from the top of the 2” nesting sq. tube.
If I consider having the screw pad retract flush, then I think I should start the first hole at 24+ inches but that doesn’t compute for the three additional holes.

Also, how far from the top of the fixed tube support is your pin hole drilled?

I’m planning on your recommendation of 9 to 11 inches spacing between each of the holes, with 1” on the aft supports.

Think I’ll pause before I drill the first hole in hopes of hearing back from you.

Thanks,

Elizabeth
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

DIMs
Aft tubes at 30”
Amid and fwd tubes at 28”
And yes, my screw pads have 24 inch long threaded sections

What is the pinhole at 4 inches from the bottom used for? Is it just another Pin position at the extremis?

Cheers!!
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Re: Trailer Jack Stand Design

Post by atomvoyager »

On my trailer the top holes in the outer tube are 3" below the top. On the aft tube the inner tube has the hole 29" below the top. I'm not sure of the dimension for the shorter center and forward tubes but it's less. The holes near the bottom of the of the outer tubes allow you to put the pin in and let the bottom of the inner tube rest on it for an additional position option. Best for you at this stage may be to lay the tubes out side by side and look at different hole spacing options that give you the most range of adjustment without needing the screw pads fully extended.
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

Thanks for the tips James!
Onward I go!!!

Elizabeth
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Re: Trailer Jack Stand Design -Thank You! James

Post by Eidoloneliz23 »

Hi James!
I’m writing to thank you for your help in getting my my trailer build dimensions correct.
The trailer turned out beautifully, and the boat fit on it like a glove,
I set up the tongue weight with a scale and she towed smoothly with a few up and down wiggles I think, due to the tongue length not having to be that long.
She is a 66 or 68 Bristol 29…. still, not sure which year.

My boat is now home under her new shed. She’s been there couple months now.
I just was too busy sailing OPB’s to pay attention and remember that I needed to write you and thank you.

THANK YOU!!!! :D

I’m now free of paying for, driving to, schlepping tools and working in the Boatyard.
It’s indeed such a wonderful thing.
Should’ve done it eons ago.

I’m back on my project, getting my workshop, set up and designing a trolley (zipline)to move my mast from the top of my boat to the side, moving to brackets on the shed posts to store until I finish my other projects
I’m also thinking about the order of my projects.

Thanks again!

Elizabeth




I’ll post a couple pictures
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Re: Trailer Jack Stand Design

Post by atomvoyager »

Thanks for the update and good to hear all is going well. Looking forward to see your refit progress.
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Re: Trailer Jack Stand Design

Post by Eidoloneliz23 »

:D
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