Gunwale mounted control line cleats bonded?

[Ed]

Hello,

I am considering moving my Cunningham and Kicker to gunwale mounted jam cleats around halfway along the racks fore and aft.

I have just seen a boat which has clamcleat epoxied in position for this purpose, which seems like a simple way to mount it.

So here is my question:
- Carbon glued to aluminium isnt meant to be a good idea due to corrosion ( i could mount it on a g10 plate for separation)
- Will bonding be secure?
- is there any reason not to bond the on?

I actually own an I14 not a cherub, however your forum and website is an excellent resource something which the 14 class does not have, particularly if you want to learn to do it yourself.
 
Hope you don't mind the outsider jumping in.

Ed

[ade white]

hi breaders, Ade White here.
i guess your alu is annodised? I would not worry too much about corrosion as it will be a localized area and quite small. How long do you want it to last? Any corrosion would take years and you would keep an eye on it. It is something i would definitely do.

Either key and bog on, or even, better bog and uni tape carbon would be stronger - just go for it - half an hour and its done.

Where are you based in the UK as I am sure there are quite a few cherub 'experts' in different parts of the country who would be willing to aid.

I am looking for a used 14 redundant mainsail to cut down for my Cherub if you have any contacts.

[Ed]

Hi Ade,

Thanks for the response, its Ed.

I am not familiar with Bog, is that epoxy mixed with fibres or a specific product?

The aluminium is a ClamCleat junior with roller, which is annodised.
The part is very cheap so when it corrodes i can just remove it and replace.

I need to fabricate the surface for it to glue to but not a big deal.

At the moment i am in the USA, but moving back next month.
Will be based in Salisbury, sailing at weston and i also work next to QMSC.

On the mainsail, i cant think of anyone right now, but i will ask around when i get back.

[Phil Alderson]

H Breaders,
i don't know much about your setup so what follows is mostly keyboard diorhea
are the racks Carbon or Ali?

Aluminium fittings bonded to carbon will corrode quite quickly unless there is some sort of barrier. The ali in a clam cleat is thick enough that it will take some time to rot through enough to break. An ali tube in direct contact with carbon can be a big problem as the ali expands as it corrodes, it can then break the carbon wrapped around it.

Using the anticorrosive paste can make a big difference.

I would be thinking about putting a plate big enough to bolt the cleats to onto the rack tube at a tangent pointing in at your blocks.
It is going to need to be strong enough to take being stood on, so will need to cope with some bending. How big is the gap between the rack and hull, what about bridging the gap?

For the plate G10 would probably be fine, you need enough thickness of plate in order to bolt the fittings to so Carbon probably won't be a huge gain.

I would probably bog (epoxy with fillers)the plate into position on the tube, and then put some fibres over the top for the upper part of the joint. I think I would put end plates sticking down from your main plate onto the tube to help stiffen the joint.

[Ed]

Hi Phil.


The hull and wings are all carbon.

A bit of background, sorry this is getting complicated but it is the easiest way to explain.

Currently
I have a pod in the centre of the cockpit floor with 4 lines going out to each side (forestay, caps, shrouds and foil) which is the perfect recipe for falling over or accidentally letting off the rig tension at any opportunity

At the front of the cockpit, you will see two clam cleats by the front wing mount on the edge. That is the vang and cunning ham.

The plan
-Twist grip foil - a la ovington twist grip and anti torsion roap UJs
- forestay at the mast base
- caps and lower shrouds to the two forward clam cleats

route the cunning and vang around the cockpit edge and up to two jammers on the edge of the hull about where the lines go at the moment.

cockpit shape

See the link below

I have a low false floor so it looks like a traditional cockpit with at least 300mm down to the cockpit floor, the top sides are maybe 15-20mm thick i would guess a a carbon foam sandwich with no increase in width at the top.


 -So i need to make a mount on the top edge of the topsides/gunwale/cockpit to take the cleat.
- so making it out of carbon scraps and have G10 where it touches the cleat may get me around this.
- or even how about just a layer of glass fiber over carbon and glue the cleat onto that?

When i work out how to post a picture i will show you what i mean.
Here is my boat, scroll down for the cockpit and spaghetti

http://theboatyardatbeer.com/international14.htm

If you dont want to click the link, google                               beer boatyard i14

Thanks,

Ed

[Torchy]

Hi,

Not sure how many turns the Ovington twist grip takes but maybe consider a simple on/off pulley system plus twist grip for fine adjustment.

We're trialling a 4:1 system doubled up  to 8:1 (runs more freely than the multi-part systems I've fiddled with when the owners weren't watching) together with the 9 turn twist adjustment which was already fitted. The plan is for the pulley to go on at the leeward mark and come off at the windward.

I was told by an i14 guy at Bartley SC that he found the ability to turn the foil off quickly and easily was essential for him,

Nigel

[Ed]

Nigel,

a good comment. There are a couple of 14s with a coarse and fine tune on the foil (GBR1537, the RMW yellow boat is one), my plan is to attempt it with only the twist grip, but if that fails i already have all the hardware in place for this system.
It does add a further 4 lines in the cockpit when take ups are there, so i am trying to avoid it.

The answer really depends on the location of the foil with respect to the pivot and also if the system is being used to pull foil on and off, which defines the moment required and any additional forces over and above the drag on the rudder and foil.

I know two of the top 14 with high aspect rudder and the foil mounted on the leading edge run 4:1 the orientation of the pulleys is also a consideration when it comes to transferring the tension effectively into torque on the pivot.
However i have heard if you dont have this set up you may need 6:1 at the minimum just so the barrel will hold itself.

The other challenge is how to get from the rudder pod out to the rudder without loading up the helm. Easy if you have a rudder gantry constructed on tube, but mine is fully enclosed.

A key point though is that have the barrel pull the foil forwards and backwards allows to you to remove the bungee which although useful for pulling foil off in waves and low speed, just adds to the force required.

I have actually intended to attach bungee pulling foil on to assist and reduce the load on the barrel, if that makes sense...

[Phil Alderson]

Ed,

Attachments are blocked for the first five posts, as a measure to stop some of the rather offensive  pictures uploaded by some spammers. In a few posts time you should see the option to add attachments below the posting box.

It does look like a spaghetti fest.

I have never tried gluing clam cleats on, if you have seen it working elsewhere OK but I would be more woried about the bond failing than corrosion. Thinking about it I have had some clam cleats bolted to carbon substructure for a few years without significant corrosion, although I do use anti corrosion paste.

[Ed]

Phil,

that makes sense.

Indeed, I am sure it is useful if you are looking for the last 1% but the mess doesnt help me.

The glued connection would be in compression and very slight sheer loading. It is one of those jammers with an integrated roller so it can take lines coming up from below.

The Killings K3 has all its control line jammes glues to the rack, but i havent seen it in person, just the image when it was new.
Link below if you are interested.
Hence asking you guys.

https://plus.google.com/photos/114706005268081611609/albums/5704630893877627825/5633453008828118786?banner=pwa
Or if you dont want to use the link. google Killings K3 go to the website and H1 (hull 1) on the right hand side for the picture.

[Will_Lee]

I think there are carbon clam cleats. If you have seen those bonded straight on I would guess it is those.

[Ed]

Hi Will,

The ones bonded on are shown in the link, they are definitely anodized aluminium.

Carbon ones are an option though.

Thanks,

Ed

[Phil Alderson]

That Killing K3 has some seriously shiny carbon on it, and is that a fixed rudder?

The glued connection would be in compression and very slight sheer loading. It is one of those jammers with an integrated roller so it can take lines coming up from below.

Remember to design to the worst load case, which could be the interaction between your foot and the cleat. Positioning says how likely that load case is.

[Ed]

Hi Phil,

Yep, so do some of the new B6s, almost too shiny.

Alot of boats have gone to a fixed rudder without cassette, guess it is lighter and one less thing to go wrong. However in the usa, they tend to launch in places with a pontoon straight into water or somewhere where it is calm so that always helps.

The angle of attack is still controlled by a pivot on the rudder pod as is common.

Remember to design to the worst load case, which could be the interaction between your foot and the cleat. Positioning says how likely that load case is.

Excellent point, i hadnt considered that. I had that issue with my B14.

I think i am tending towards laminating a g10 plate and bolting it directly to that.


Thanks for the discussion.