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Show me you attachment! (bob stay specifically)


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need to get a bob stay fitted to the prod, and keen to see different attachment methods, both boat and prod end.  Prod is already attached to boat securely, but adding a bob stay now to run a FRO.  All pictures/comments appreciated

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I just added a hole through the bow on my boat for the bobstay. Making up a custom bobstay out of carbon and aramid wound between 2 points. Cow hitching the bottom through the hole and lashing the top. This will be retractable so the bobstay cant have any stretch as you need to be able to tension the bobstay with the prod out line. 

On motorboat we had a D ring through the bow and the bobstay went to half prod as the angle was too tight to go to the end and added too much compression into the prod. This worked well as it was also the code zero point.

On the sunfast we had a dogbone inside the boat for the bobstay as it was in the anchor locker so didnt need to be sealed as well. That was the tidiest way as the bobstay just disappeared into the bow.

Are you running a fixed or retractable prod? 

20210516_163831.jpg

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You can see out motorboat prod setup there. We had 3 tacklines. One at half prof for the upwind zero is where the bobstay attached, then one at 3/4 prod for the FRO(Fractional reaching zero) and then the one at the end for the gennaker which was 1:1. The 2 zero tackiness were 2:1 for the furler which is essential to stop the furler from twisting. They are both fixed length strips which were dead ended back to the prod to eliminate extra compression on the prod by having the tackling loading aft as well. 

We made it bullet proof after breaking it at off milford sound  in the Round NZ race so we could push that bus hard all day long. 

FB_IMG_1621673584025.jpg

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We have a fairly simple system.

Prod end is spliced through carbon tube but the stay goes through the tube and over the top and then back through and spliced to itself so it takes weight on top, don't have any close up pics of this.

Then on the stem we have a wichard D bolt and stay is lashed with a low friction ring.

IMG_20210522_222934.jpg

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12 hours ago, Kick Ass said:

We have a fairly simple system.

Prod end is spliced through carbon tube but the stay goes through the tube and over the top and then back through and spliced to itself so it takes weight on top, don't have any close up pics of this.

Then on the stem we have a wichard D bolt and stay is lashed with a low friction ring.

IMG_20210522_222934.jpg

Who made your prod ?? Planning something very similar for an E7.8 

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3 hours ago, 44forty said:

Who made your prod ?? Planning something very similar for an E7.8 

DIY Project with my dad.

Made a pattern of the bow and made a a jig. Laminated timber and carbon unis into a carbon tube then wrapped it all in double bias carbon.

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30 minutes ago, Kick Ass said:

DIY Project with my dad.

Made a pattern of the bow and made a a jig. Laminated timber and carbon unis into a carbon tube then wrapped it all in double bias carbon.

Well done  , it looks mint . Will be doing almost the same but with foam and tube and it will be removable so it doesn’t go through back window of the car when it’s on the trailer 

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5 minutes ago, 44forty said:

Well done  , it looks mint . Will be doing almost the same but with foam and tube and it will be removable so it doesn’t go through back window of the car when it’s on the trailer 

Thanks, would have done foam if I was more comfortable with laminate schedules to get strength.

Dad is a wooden boat builder from the 80's but not up to play with the modern composite methods hence using timber.

Has been well tested with an RNI and plenty of other testing miles!

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23 minutes ago, 44forty said:

I will let you know on labour Monday if our laminate schedule was strong enough ! 
 

did you use a hardwood or cedar or ? 

👍, Used hard wood.

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my prod is fixed and under a metre long.  Same tackline to be used for gennaker and FRO,  i am thinking about drilling thorough at the same height but about 50mm further back than the little grey square.  from the square forward i can see light through the glass so need to be further back to be in the foam core.  This would also mean it is above the sealed section in the bow that i am keen to leave alone

Prod 1.jpg

Prod2.jpg

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43 minutes ago, Young Entertainer said:

my prod is fixed and under a metre long.  Same tackline to be used for gennaker and FRO,  i am thinking about drilling thorough at the same height but about 50mm further back than the little grey square.  from the square forward i can see light through the glass so need to be further back to be in the foam core.  This would also mean it is above the sealed section in the bow that i am keen to leave alone

Prod 1.jpg

Prod2.jpg

I don't think you would want to be in the foam core, solid glass in the stem would be strongest?

Just looking at your setup you could gain another 100 or so mm if you had a snout machined up for the end of the prod and run you tackline through the tube?

We have a snout with 2 exit holes to run 2x tacklines, 1x 1:1 for A sails and 1x 2:1 for Fro

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Plus 1 for what Brendan(kick) said about the solid glass on the bow and the tackline through the prod into a snout. 

I reckon a machined acetal snout that sticks out another 30mm with 1 or 2  verical holes for the bobstay lashing and 1 or 2 horizontal holes for the internal tackline is your best bet. 

Even if you dont run an internal tackline you can have a short strop with with a friction ring for your 1:1 tackline and the dead end point for your 2:1 with the fairlead aft being a low friction ring on your current tack line attachment. The tackline can just be a fixed length strop which goes into your bow cleat to pull the furler out. 

Guessing the rusty hole is the bottom of your anchor locker? Probably to high to put the bobstay into the locker with a Dogbone. What's the hole below it or is that just a mark? 

I will call you tomorrow to talk more about it.

 

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The rusty hole is the anchor locker, the other mark (duct tape) is the bottom of the open area i an get to under the anchor locker,  if i stick to the solid glass then i can put the tube at about that mark.  and glass it back to the boat internally and potentially fill the area around it with glue.  Definately planning on getting a cap made up forthe end to tidy it up and five be attachment points for both bobstay and tacklines

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Bobstay is going to cause you some issues for the anchor.  What's the tube wall thickness? If it's more than about 6-7mm then you could maybe do a bobstay to the half prod from the anchor locker. Then it would all be behind your anchor and never catch. Just a thought.

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Our Prod is about 2 meters long and has a stainless bobstay so that it is supported without any halyards attached. I'm almost 90kg and can climb out to the very end and it remains supported. I'll post pictures of another prod too...

IMG_5128.JPG

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Other prods and prod hardware that my friend builds then anodizes...

 

IMG_2271.JPG

Furlers close up.jpeg

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6 hours ago, 2flit said:

Our Prod is about 2 meters long and has a stainless bobstay so that it is supported without any halyards attached. I'm almost 90kg and can climb out to the very end and it remains supported. I'll post pictures of another prod too...

IMG_5128.JPG

Looks cool - what does it weigh? 

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