Aluminum vs SS bimini frames

rgranger · Mar 17, 2021

NINEv2 said:
And if anyone has suggestions how to deal with the split backstay passing thru the bimini I'd love to hear them!

It is called a backstay slit.

How to Add a Backstay Slit in a Bimini

DetailsDo you have a bimini that’s already been sewn and constructed but you need a backstay slit added to the aft edge? Our how-to video instructions will show you how to install a backstay slit in a fabricated bimini. Our backstay list has a zippered enclosure so you can keep the slit closed...

www.sailrite.com

31seahorse · Mar 17, 2021

Hello NINEv2,
We have used both Aluminum frames and Stainless Steel frames on a variety of boats. Aluminum frames are far less stable than the Stainless Steel ones. There are also choices for 1 inch diameter or 3/4 inch diameter in Stainless Steel. Regarding cockpit measurements: Some bimini frames are anchored on the cockpit coaming while others can have anchoring arms to the stern rails if they are on your model of sailboat. Some bimini frames are secured either fore and aft or one of those ways using strapping. More sturdy designs are attached with clamps. There are many options, including looking for second hand frames that can be used as found or modified to fit your boat.

Capt Robbie · Mar 17, 2021

back stay slit, zipper or laced.

stainless is stronger especially at the connecting fittings. Aluminum will oxidize and pit wherever it is exposed to elements.

Tom J · Mar 17, 2021

As 31seahorse mentioned, some bimini frames are secured with straps, and others use clamps. I'd strongly suggest avoiding using straps, since they tend to loosen, and are always in the way. Running a section of tubing from the frame and clamping it to the stern rail is a much more secure attachment.

Tom J · Mar 17, 2021

This picture shows the tubing securing the frame of our bimini. Stainless steel, obviously.

garymalmgren · Mar 18, 2021

but is the difference between the aluminum vs stainless construction significant enough to warrant such a price difference?
In my opinion, NO
Here is a pic of my trailer sailer. This is a workhorse that has been through the mill. Not fancy but pretty sturdy.
The Aluminum frame and fittings have stood the test of time. 20 years of abuse.
Daughter at the helm.

gary

rgranger · Mar 18, 2021

I think @garymalmgren makes a good point. Is your boat pristine? A showpiece? Then maybe an SS bimi makes sense. Is your boat a 30 year old knock-about? If so, then an SS bimi would be akin to lipstick on a pig.

You boat, your money, your decision.

Justin_NSA · Mar 18, 2021

I've owned both, AL and SS. IMO, the attachments to the boat separate the good from the bad.

Scott T-Bird · Mar 18, 2021

$1,500 for SS-framed bimini from CD doesn't sound bad at all to me. I wouldn't put one of those cheap Amazon jobs on my sailboat. I put a cheap aluminum one on my ski boat but rarely used it. It was put on the boat only for lazy occasions. But I could leave it in the garage when it wasn't going to be used. On a sailboat, where the bimini is likely to be on the boat all the time, I would be sure to upgrade for all practical purposes. I like the look of the solution that @Tom J shows.

rgranger · Mar 18, 2021

NINEv2 said:
Thanks everyone, decisions to make for sure. I was able to find a model for ~$500 but still. I can buy 3 of the aluminum frame jobs for that price.

The slit videos (do we do phrasing here?) are also going to prove very useful. Thanks yet again rgranger.

Best sealant for the inevitable screwholes going into the hull? I don't have the terminology yet for where it will attach... still a total rook

Bed-It Tape has become the consensus backing compound of choice. I purchased two roles from @Maine Sail years ago. The stuff lasts and does a great job. If you do a member search for main sail, you can find a link to his store at the bottom of his profile. And the terminology you are missing is "gunwale" or "scupper" depending on how your boat is designed

Barnacle Bill · Aug 30, 2021

Stainless for sure.

Ward H · Aug 30, 2021

NINEv2 said:
That's some nice work there. Where would one go to find such mounting hardware and tubing? Surely that isn't electical conduit from the local hardware store yes?

A little late I know, but Defender.com, Sailrite.com and finally Amazon. I've bought bimini parts from all 3.

sail sfbay · Aug 30, 2021

To answer the OP's question in the title: Bimini top frames are available in aluminum and stainless steel. In freshwater environments, aluminum is probably adequate for your needs and much more economical. Aluminum tubing should be anodized to resist pitting and oxidation. Stainless steel is much stronger, will not corrode, and is nearly twice as expensive as aluminum. All my boats have had/have stainless steel bimini frames. You might find this article helpful: What Type of Metal for Your Bimini Top Frame - TopMaster TopMaster Marine

NYSail · Aug 31, 2021

Call a local canvas shop and get a quote…….

good luck
Greg

Project_Mayhem · Aug 31, 2021

NYSail said:
Call a local canvas shop and get a quote…….

good luck
Greg

My bimini was much more difficult to make and is probably bigger than what you'll need for a Cat 22. PO said he paid 1100-1200 at a local canvas shop. It's made from 7/8" stainless and is very strong. People grab it and I'm not worried about it bending. It also uses four straps. We typically use 3-4 of them. We often leave the forward strap loose on the side we dock on for easier access. We've sailed in high winds with as little as two straps. It's never been an issue.

I recently made a solar mount out of a 1" stainless bimini bow. That stuff is ridiculously strong! I would definitely look at an aluminum frame if I were buying a bimini.

As others have posted, butyl is most people's sealant of choice. If you use to much I suggest taking care of the excess sooner rather than later. It's just easier to clean up if done right away and doesnt get tracked to other parts of the boat

Tom J · Sep 3, 2021

NINEv2 said:
Zombie thread comes back to life...

That's some nice work there. Where would one go to find such mounting hardware and tubing? Surely that isn't electical conduit from the local hardware store yes?

I believe my bimini and dodger were installed by the Catalina dealer when the boat was new.

FastOlson · Sep 3, 2021

That cheap Alum. frame will corrode. When you or a crew member lurches and grabs onto it, there is risk of an injury when it flexes, bends, and warps -- and person depending on it may fall. It is not even close to the rigidity of SS.
The SS tubing is expensive, the attachments are expensive, and the bending machinery costs too. This is "skilled labor" work.
If you just want cheap shade, you can use Aluminum or even home-brew pvc tubing. Just be aware that the tradeoffs are significant. Very significant.

Aluminum vs SS bimini frames

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