Mounting Blocks

[mcrem]

I am looking to reorganise the running rigging on my Teign 7 metre so that all the work can be done from the cockpit area (getting too old to keep clambering up to the mast where the main and fore halyards are currently terminated on horn cleats).
Perhaps not a difficult task but I would still appreciate some guidance.
I think I will need a max of 5 blocks to turn the halyards from the vertical to horizontal - main and fore halyards, topping lift, main downhaul and perhaps lazy jacks. I have already converted the mainsail from rope luff to slides.
I had thought of mounting the two load bearing blocks (main and fore) towards the base of the mast (alli -about 20 years old) using rivets, and the non-loadbearing blocks (downhaul,topping lift and lazyjacks) to the cabin roof at the mast base.
How safe is it to drill and rivet the mast? Also, would removing the redundant horn cleats weaken the mast in any way?
All advice and ideas appreciated.

Mike


<hr width=100% size=1>

 

[snowleopard]

it's more common to mount the turning blocks to the mast step. any new holes in the mast weaken it to some extent so best avoided if poss. alternatively mounting to the deck with ply pads & penny washers is possible.

if you remove redundant cleats you can bung up the holes with pop rivets, it won't improve the strength but will tidy things up and prevent whistling!

<hr width=100% size=1>

 

[snowleopard]

it's more common to mount the turning blocks to the mast step. any new holes in the mast weaken it to some extent so best avoided if poss. alternatively mounting to the deck with ply pads & penny washers is possible.

if you remove redundant cleats you can bung up the holes with pop rivets, it won't improve the strength but will tidy things up and prevent whistling!

<hr width=100% size=1>

 

[oldsaltoz]

I agree with Snowleapard, If you have no tabernacle consider fitting an angle iron profile in aluminium on each side of the mast with suitable backing plates; you can then shackle your blocks to them as required.

Note,
When drilling the holes through the deck and backing, drill them 5 mm oversize and fill with resin and micro fibres to seal the raw glass. then re drill to the required size.

Avagoodweekend.....



<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[William_H]

I agree with all the relies except perhaps the drilling then filling with resin is more fussy than I would be prepared to do. My poor little boat is probably like a swiss cheese of holes filled and new ones made especially in the cabin top. I have pulleys on saddles with washer backing on the cabin top for main halyard (winched tight) and have never had concerns about cabin top strength. Are the halyards internal or external. Assuming they are internal I imagine they exit from the mast via an elongated hole well above the cleats. I have decided this is the best arrangement rather than turning blocks in the mast base although I have seen mast bases with blocks bult in that work well. You may be able to mount your turning pulleys around 30cm out from the mast base so that with a little angling across the hatch you don't neeed more turning blocks hence less friction. Get some small winches for the cabin top they can make life really easy Mast strength is not an issue as near the base all loads are compressive. certainly don't worry about cleat fastener holes. regards will

<hr width=100% size=1>

 

[mcrem]

Thanks to all of you for your thoughts - I appreciate the input.

Mike

<hr width=100% size=1>

 

[Rick]

The necessity to overdrill, and fill in glass comes about only when the deck is cored - if foam or balsa, then do as siggested, otherwise just drill and affix.

In order to achieve your aims, I'd suggest you look at leaving lazy jacks and perhaps topping lift off your list of lines aft, so long as the boom rises when main fully raised. Having said that, look to whether you need downhauls on both main and headsail, as there's nothing worse than one or other coming halfway down, and then needing a quick trip forward to complete the task.

<hr width=100% size=1>

 

[BrendanS]

If you drill through any fibreglass, you are exposing fibre that can wick moisture. Not a bad idea to seal it. Nothing to do with cores IMHO

<hr width=100% size=1>Me transmitte sursum, caledoni