Jump to content

Line choice for centerboard pennant


Recommended Posts

One of my winter projects is to replace the centerboard pennant on my J/95. 
 

The current pennant appears to be 3/8 line with a Dyneema core and the cover stripped, (or 1/4” Dyneema with a cover added). The cover is on the part of the line that is exposed when the board is retracted. 

The pennant seems to be under a great deal of tension when raising the board since the pennant leads to a 4:1 purchase and a winch is still required to raise the board. So, I want to go for strength.  

I’m wondering why I wouldn’t just go with all Dyneema. I thought Dyneema didn’t need sun protection? Am I mistaken, or is there possibly a reason for having a cover on deck?

 

Any advice is appreciated. 
 


 

 

Link to post
Share on other sites
28 minutes ago, Quickstep192 said:

One of my winter projects is to replace the centerboard pennant on my J/95. 
 

The current pennant appears to be 3/8 line with a Dyneema core and the cover stripped, (or 1/4” Dyneema with a cover added). The cover is on the part of the line that is exposed when the board is retracted. 

The pennant seems to be under a great deal of tension when raising the board since the pennant leads to a 4:1 purchase and a winch is still required to raise the board. So, I want to go for strength.  

I’m wondering why I wouldn’t just go with all Dyneema. I thought Dyneema didn’t need sun protection? Am I mistaken, or is there possibly a reason for having a cover on deck?

 

Any advice is appreciated. 
 


 

 

Could be extra chafe protection

Link to post
Share on other sites

You mention the line goes to a winch and likely also a clutch although you do not mention it. The stripped end could be so it is bare dyneema in the area where it will get wet inside the trunk so the line will be less nasty than if it had a polyester cover in the wet section. Also the stripped part could be a factor of the size of sheaves (width) inside the trunk.  Bare dyneema does not grip well on winches or in clutches

With a 4:1 the dead-end is inside the boat so it may be possible to replace the line in place. 

Link to post
Share on other sites

I should have included some pictures. 
 

One end of the pennant is connected to the board; the other end is connected to the 4:1 purchase on deck. No hands need to touch this part of the pennant. 

As you can see on the picture, the cover is stripped where the line goes through the deck. So, as the board is lowered, the part with the cover traverses that block and goes below. 
 

On deck, the “other” end connects to the block and tackle. So, no one ever has to handle the pennant, it just has to bear a lot of weight. It raises the board from the forward end of the board, rather than the aft end, so it not only bears the full weight of the 250# board, it has to deal with all the leverage too. 

Fortunately, because the boat is not kept in the water, the line is only submerged when sailing. Also, it doesn’t have to hold the board up when at rest. On the flip side, if the pennant were to break and leave the board hanging down, I wouldn’t be able to get the boat back onto the lift.

Oh by the way, the pennant has to be a specific length and have an eye at both ends. Part of me wonders why they didn’t use wire. 
 

Anyway, I look forward to more wisdom. 
 

 

CFF03522-ACD4-4202-BA0F-4F14F20BD69C.jpeg

C11ECA2D-5B15-4A82-B5E6-BFFF1ECD8DCD.jpeg

Link to post
Share on other sites

We have a daggerboard on a 40' Farrier trimaran and the board needs to be winched as it gets 'sticky at the top end and the bottom end of it's travel. The up-haul line passes thru a cheek block, a low friction ring, and then a deck organizer on it's way back to the cockpit. There is no block and tackle arrangement. Our line leads thru a clutch and then to a Lewmar Ocean 30 winch. 

We do not raise and lower our board while sailing since the trimaran goes as fast down wind with it down. We leave the board down. So we might not be using our control lines as often as you do.

I don't know how yours was designed to work. The block and tackle suggests to me that it was designed (origionaly) to be hauled by hand.  If you are using a winch... do you think you still need the 4-part plus a winch?  Do you sometimes use the 4-part without the winch?  If not...Maybe try simplifying the situation by eliminating the 4-part and use just the winch to raise the board. 

We have 11mm Endurabraid from New England ropes. It has the polyester cover left intact. Before this we had a T-900 haul line and we needed to add a small 5" section of Dyneema chafe sleeve a one area that was just starting to cut the cover, this worked fine for another three years. We have needed to replace our lines once in five years of sailing (Orcas Is, WA to New Zealand).

If you have any chafe issues on the polyester cover... I would remove the cover except for the part that might touch the winch. If your chafe issues are  bad - (or you are concerned about UV damage > which can be a long term issue for Dyneema) - I would cover the striped portion with a 1/4" Dyneema chafe sleeve for its entire length up to the point where the original polyester cover is left intact.

Starboard side Control Lines.jpg

Link to post
Share on other sites

Thanks for sharing the pics. From the look of things the pennant between the board and the tackle appears to have a cover so it is covered on the section when the board is down. This cover helps protect the line from sunlight and chafe. The sunlight issue is not as large with dyneema but it still degrades, chafe especially from the line being stepped on and smashed into the non skid is a bigger issue. I would likely do a similar pennant in the same fashion but with a dyneema cover versus a polyester cover. For tweaking the length a lashing at either end of the pennant would give you some range and if done in a tidy fashion still pass over sheaves if needed. 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...