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General Upholstery Questions and Comments => General Discussion => Topic started by: Allan on April 10, 2011, 11:15:21 am

Title: Bow Sizes
Post by: Allan on April 10, 2011, 11:15:21 am
Somewhere I have seen a web site or a file on making bows for bimini covers etc. outlining the diameter tube sizes for a particular span etc.

Does anyone know where to find this??

I have a friend building a 30 ft sailing catamaran
I have done all the covers for the boat and about to do the tramps but now he wants a bimini to cover the cockpit and it is pretty wide.

Title: Re: Bow Sizes
Post by: Mike8560 on April 10, 2011, 03:05:09 pm
I'd say 8 1/2' wide is pushing it for 7/8" tubing.
Over that I'd go 1"

Altought my bayliner 2318 ha a skonney bridge  with 1"
Title: Re: Bow Sizes
Post by: fragged8 on April 10, 2011, 07:26:23 pm
I mostly use 1" and dont bother with 7/8" as it's just more steel
to stock, the smallest i do is 3/4 but only for boats up to 22-23ft
Title: Re: Bow Sizes
Post by: Peppy on April 11, 2011, 12:42:15 am
This is what your looking for?

I'm not sure I agree with every thing he says though. I forget. I read it a while ago.
Title: Re: Bow Sizes
Post by: Allan on April 11, 2011, 01:47:31 am
Thanks Peppy

Getting closer but not the one
The one i am thinking of had diagrams etc.

The bows on my one will be in stainless steel not alloy so that has to be taken into consideration also

Title: Re: Bow Sizes
Post by: JuneC on April 11, 2011, 01:46:08 pm
I saw a wide-beam bimini lately where the fabricator had put in supports at an angle between the upright part of the leg and horizontal, only on the inside bows.  It was a very large top, but still done in 7/8".  In spite of the angular braces underneath, there was no impact to headroom.  Rather clever design.  I should have taken pictures.

Title: Re: Bow Sizes
Post by: Mike8560 on April 11, 2011, 02:01:52 pm
Formula used to have a vertical
support at the rear bow June to prevent  side to side shake
Title: Re: Bow Sizes
Post by: Allan on April 11, 2011, 10:13:14 pm
This bimini is to be 3.1 meters wide and 2 meters deep
I am trying to talk him into a hard top with clears around the sides and front rather than a soft top

Title: Re: Bow Sizes
Post by: regalman190 on April 12, 2011, 01:31:58 pm
I agree....anything over 8-1/2 or 9 foot should be 1". However, if I'm adding a camper back to an already existing enclosure, I'll usually match what is already there and add supports. And, I've seen a lot of wide beam boats with 7/8 tubing, usually stainless, not aluminum. Don't know if I agree, but they are out there.
Title: Re: Bow Sizes
Post by: Mike8560 on April 12, 2011, 04:48:37 pm
Seems photobucket is having maintanance.
Funny thing on bows when I first started canvas I did t bend tubing. I just used thoose kits with the 7/8" aluminum 3 piece per bow kits you  rivited together  probley have used them.
Anyway a guy with a 36 or 38 carver aft cabimhad a bridge Bimini but wanted to have a top on the adtdeck that attached to the bridge with an enclosure   New. CAnvas on the bridge also.
So I built a aft deckk frame with theese kit I think I had 2 of the crown sections to make it wide enough
and upright supports at the stern rail to add suport.
It tuned ok ok a d the customer loved it.  It was my first larger boat  and I did t want to turn down good money at the time  after that I got a bender  lol.   
Title: Re: Bow Sizes
Post by: RandyOnR3 on April 13, 2011, 03:30:17 am
   around here, Marine Canvas is our speciality..   I uasally use 7/8s up to about 8 feet max, and then switch to 1 inch up to about 9 to 10 feet.. anything over 10 feet I use 1&1/4...... and if the boat is a sailboat and used Offshore, 1 inch stainless for smaller boats and 1&1/4 for anything 32 feet and above..
   The 1&1/4 is a bear to bend but sure comes out pretty when finished and allows the use of the Bimini to be used as a rack for solar panels if desired.. done a few of the bimini / solar installs.....