Saturday, November 10, 2018

Upgrading the Mainsheet Block System

Yes, we're still making improvements to Eximius and this one is a long time coming.

The Mainsheet (the line that controls the position of the Boom) runs through a total of 9 Sheaves (the pulleys inside a block) and 7 of those are original to the boat, so they are going on 31 years old. I have cleaned and lubricated those blocks many times, but it really does not make much difference.
Normally, the crew will 'play' with the Mainsheet and the Traveler to keep the sail shaped appropriately with changes in the wind.

To explain how bad the blocks work: In order to ease the boom from the centerline, even when the sail is full of wind pressure, we have to ease the Mainsheet by pulling on one of the lines in the Mainsheet block system and then letting it go so that the boom moves and takes up the slack. In order to move the boom back towards the centerline we have to use a winch! Consequently, we often position the Mainsheet and let it be, even if we need to move the sheet unless it's a significant sailing status change like from Close Hauled to a Beam Reach..

This means that we don't get the best speed from the boat! We updated the Traveler a while ago and that does give us a decent amount of change but it does not encourage correcting mainsail twist, and hence boat speed.

Scouring the Internet for replacement blocks, with a preference for Garhauer equipment, matching the new Traveler and new Deck Organizers, I was dismayed at the pricing, it looked like we would have to pay around $650 for the set of blocks, Dang! and we're watching the pennies as we had to buy a new truck earlier this month.

Peggy asked what kind of blocks were sold by Catalina Direct for the C34, hadn't thought of that! A quick review of the CD site and I found they had a C34 Mk1 Mainsheet Block Kit for $266.
Image from Catalina Direct

The kit comprises

  • 3 Single Blocks with Shackles
  • 1 Single Block with Shackle & Becket
  • 1 Fiddle Block with attached Single Block with a shackle on the Fiddle Block
When I called Catalina Direct, they confirmed the blocks were Garhauer Blocks - awesome!

I didn't need the 3rd Single Block as I had replaced the block at the base of the mast already.


The cost bottom line was $246.70 for the kit and shipping after the discount for not needing the 3rd Single Block. The new block kit is on it's way and should arrive by late next week.

Peggy is pleased because we have been discussing sail trim a lot recently and it would make a huge difference if she could adjust the Mainsheet, and this kit should enable that.

I'm hoping that the end of the sheet, which attaches to the becket in the middle block on the Boom, will easily transfer to the new becket, else I'll have to re-splice that eye. The rest of the Mainsheet should just thread through the new blocks.

Here's a pic of the completed installation. 

I didn't need to make a new eye on the end of the Mainsheet, it fit the becket on the upper middle block just fine.

The astute will notice that there is a twist in the sheet (black & white rope) at the additional block on top of the Mainsheet fiddle (click on the image to zoom in) That's because that extra block is from the old setup and is too big! The kit was sent without the extra block because they were out of stock for that item, it's slightly smaller than the old block and it will not be on a swivel.
A nice feature of the new blocks: The shackle pins are threaded into the shackle and have a securing ring though a hole drilled through the threaded portion of the pin. I much prefer this setup to one where the pin is secured only by the ring. Nice job Garhauer!

The difference in friction between the old setup and the new, with the passing through 9 blocks and 1 rope clutch, is staggering! I can now ease the Mainsheet by opening the clutch and then applying a few ounces of pressure on the boom (which would be done by the wind on the sail).

We have a working Mainsheet! WoooHoo! Of course, we're not sailing for at least another week!

But we'll see you on the water!

Paul