Boat: Murray 33-Chouette & Pape Steelmaid-44-Safara-both steel cutters
Adding Internal Halyards
have two spare sheaves already, but don't have the exit plates.
Here are some pics. Sorry I don't have a good pic of the lower mast.
My question is does anyone have good instructions for installing exit plates? I have heard that you should stagger them but I would like to get some better guidelines before having at my mast with a saw and drill. Past experience suggests I can't be too careful with power tools.
I don't know the manufacture of the mast.
On a side note, any idea of how the top sheaves are mounted? I didn't see any pins and the top of the mast appears to be welded. The sheaves spun OK.
I should have spent more time looking around while I was up there but....well, it wasn't the most relaxing experience.
Am doing the same with my mast, going from two external halyards to four internal (not counting the spinnaker and staysail halyards that are on external blocks).
Happened to find a sister ship that had done the same a few years ago and after many bluewater miles was very happy with the change and had found no problems.
In general, the positioning of of the exit plates does not seem to be critical. Just pick locations on the mast that are clear of obstructions (don't foget to check for internal wiring and conduits) and give a good fairlead to the halyard winches or blocks, however your rig is set up. For me I also wanted to make sure they were high enough so I could reach up and get a full height grip on the halyard for initial hand over hand hoisting.
The only other concern I can think of is make sure you stagger the holes in the mast so they are not in the same vertical or horizontal planes. Putting the holes all close together could create a weak point on the mast.
DISCLAIMER: Cutting holes in your mast could result in a weak spot that could contribute to mast failure. I have not inspected your specific mast nor am I a trained rigger. Any work or modifications on your mast is at your own risk.
The water is always bluer on the other side of the ocean.
Here's a photo of the stbd side of my mast where the halyard exit holes are. They are staggered as previously described by several.
I recommend that you go to a rigger/rigger website and get the dimensions for the cutout hole so their inserts will fit. I determined (unlike the previous owner) that I had an Charleston Spar/Isomat section, and was able to get phenolic inserts for the exits that reduce line wear and water ingress.
At the top, there is usually a plate screwed onto the mast section on the side over the end of the axle that the sheaves ride on.
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Re: Adding Internal Halyards
I did exactly this some years ago on a Yankee 30, and had no problems with the existing sheave sizes. Some considerations of matching sheave profiles to the halyard material, though. Did you plan to use wire or rope for the halyards? If wire, you should change the sheave for one designed for that usage. Otherwise, just go for it and she'll be right, mate!
Jim and Ann
s/v Insatiable back in MBTBC marina, waiting for next eye jobs to be done