flimsy bimini

[troypolla]

I have a bimini with the sunbrella canvas on it, but when it is open while driving it shakes from side to side bad enough to be concerned about it. It has the supports in the back but the straps in the front. It also has the nylon rear and middle supports. looks similar to this.
How can I stregthen the top so it does not shake from side to side while driving. Stainless attachments? support braces in the front?
http://www.overtons.com/modperl/overtons/detail/pdetail2.cgi?r=detail_view&item_num=34372&fcat=2D1A

 

[bruceb58]

Re: flimsy bimini

At what speed does this occur?

 

[troypolla]

Re: flimsy bimini

well the top speed of my boat it only 40 so... in a range of speeds. really only when hitting waves or the wake of a passing boat. If the water is smooth it does not happen.

 

[bruceb58]

Re: flimsy bimini

It is the diameter of the tubing that is going to determine the rigidity.

What diameter tubing is the top made out of? What is the wall thickness? Stainless or aluminum? What is the height of the top?

If it turns out to be a tubing issue, you can either replace the frame(expensive) or add two straps at an angle to reduce the sway.

Would be nice if you could post a picture of your top and how/where it is strapped down.

 

[troypolla]

Re: flimsy bimini

The tubing is 1 inch diameter.
I will have to get back to you about the wall thickness.
It is aluminum.
The height of the top while open and on the boat is about 6.5-7.0 feet.

I will try to post pics tomorrow if need be.
It has 4 posts to stand on and the two straps in the front to keep it open. I tried to tighten those straps to help control the problem, but I dont think it helped.

 

[QC]

Re: flimsy bimini

I don't believe that this is about tubing size or the mount material. Many of the latest biminis with fixed rear supports have a single angled piece placed laterally to control that side to side sway. I had trouble finding a good pic, but this one shows the concept. Cobalt, Chaparral, SeaRay etc. are all doing this now:

 

[willamettejeff]

Re: flimsy bimini

Sizing and mounting so that the main poles must be sprung either outward or inward to attach to hinge mounts will greatly reduce side to side sway.

 

[tashasdaddy]

Re: flimsy bimini

here's a shot of my Chris Craft with the diagonal rear brace:

 

[steelespike]

Re: flimsy bimini

Those braces look like they would do the job.
If you didn't want to do a brace maybe a couple of straps in the same spot would help.

 

[troypolla]

Re: flimsy bimini

The bimini is an 05 as is the boat. But this has really helped me . I will try a few ideas. You can buy the support poles seperately i think.

 

[Texasmark]

Re: flimsy bimini

Little off topic.

Had a custom bimini built for my boat. Wanted it to survive rough water and high speed, jamming into tree branches while fishing and all, so I figured SS was the material of choice. Had had alum's before and had bent tubes on occasion.

Was plenty tough alright, just hard to lift due to the weight of the SS and the deluxe, rubberized, lined, canvas and all that I just had to have. Since the top was large for the size of the boat, it added appreciably to the boats weight and affected stability.

Also, the mounting brackets were zinc regardless of the tubing material and they seemed to be a weak point, but didn't fail on my watch.

Mark

 

[QC]

Re: flimsy bimini

BTW, I have severely bent SS bimini tubing before. Front strap seam failure running around 50 into a head wind. Could've been nasty . . .

 

[Texasmark]

Re: flimsy bimini

Hear you on that. At 50 + headwind you had some serious pressure against that thng.

Got me on a couple of things. What does BTW mean and jtexas C & P ?

Thanks,

Mark

 

[tashasdaddy]

Re: flimsy bimini

BTW is by the way

 

[QC]

Re: flimsy bimini

jtexas cut and paste. Giving credit to anyone that I steal a signature from . . .

 

[QC]

Re: flimsy bimini

Another BTW . . . I did repair that bent SS bimini frame with a tube bender. It amazed me how hard I had to pull on the bender after the pretzel the forces made it into in a heartbeat :0 Still run it at 50ish even into the wind; I just watch my front straps real careful like