Choosing a Replacement U-Bolt for a Boat Trailer

Updated 02/07/2025 | Published 01/30/2025

Question:

Hi, Were replacing the swivel bolster brackets and U-bolts on our boat trailer and I am trying to locate the best fit in a 7/16inch diameter U-bolt. Our steel tube cross member measure pretty close to 1.5inch W x 3inch high. I had already ordered galvanized swivel bolster brackets but still need the U-bolts. I understand some come with new flat washers and nyloc nuts. Though that may not be critical. For now I just need two U-bolts for one of the two cross members on our boat trailer which has a 1200 lb. carrying capacity. Given I ordered the galvanized bolster brackets I am uncertain in regards to using either zinc or stainless given Im not sure if their considered dissimilar materials which could perhaps cause galvanic corrosion. Your input on the with and length of 7/16inch diameter U-bolts along with product numbers would be helpful. Thanks

asked by: Dave

Expert Reply:

Hey Dave, it's great to hear from you again!

The CE Smith U-Bolt - Zinc-Plated Steel - 3" Long x 3-1/8" Wide x 7/16" Diameter # CE15252A you were looking at could work for if the dimensions match what you currently have. You won't get any galvanic corrosion by mixing those materials - it really only happens with aluminum.

If you can let me know the dimensions of your current U-Bolts I can see if we have something that's the same for you.

expert reply by: Jon G

Dave

1/31/2025

Jon thanks for the info on corrosion. I heard that sometimes either stainless or aluminum may have corrosion issues with galvanized. I wasn't certain what info on that was correct. Now I know regarding zinc and galvanized materials. I believe the dimensions on the CE15252A are comparable or better than my existing U-bolts but I don't have a sketch or such identifying where the provide dimensions apply to the actual U-bolt. Any chance you could provide a sketch of the U-bolt that illustrate the inside width, inside length to end of the threads and the actual length of threads? I suspect the inside width is the 3 1/8" and since my cross members are 3" in height that measurement appears to work. The 3" inside length should actually work better than what I have around 2 5/8" as long as the threads are of sufficient length. I would get 2 of these if the measurements info can be verified with use of a sketch. I'm trying to verify with CE Smith also but haven't heard back from them yet. Dave

Jon G.

1/31/2025

@Dave Stainless and galvanized will be fine together, it's the aluminum that has issues with other metals. I don't have a way to add a sketch to a comment, but I can say that the inner dimensions are 3-1/8" wide x 3" long and the threaded portion is 2" so this will work great for what you described.

Dave

1/31/2025

@JonG Thanks for both of your recent comments! I will order 2 of these CE15252A kits for now. Dave

Jon G.

1/31/2025

@Dave Happy to help! Let me know if you end up having any other questions!

See All (5) Replies to Dave ∨

Dave

1/31/2025

Jon, it would also help to know if the nuts with the CE15252A have Nyloc inserts. I could use Nyloc's or can purchase from the hardware store if not. Thanks Dave

Jon G.

1/31/2025

@Dave The nuts are Nyloc nuts so you're good on that front as well.

Dave

1/31/2025

@JonG Thanks!