Siting chainplates for deck stepped mast

[HoneyRyder]

Hello all,

My question relates to siting the chainplates for a deck stepped mast.

Is there any problem running the shrouds to chainplates that are 7 feet below a deck stepped mast?

I am stepping the mast on the top of the pilothouse, which is 7 feet above the deck.

It's a 33' mast going on a 44' pilothouse trawler, and really only intended to use sail going downwind(ish) or in engine fail emergency to either get home or to get off a lee shore.

I have an additional mizen stepped further aft (steadying sail) already but am looking for a little more oomph.

All info gratefully received.

Honey Ryder

[Diesel Bill]

My biggest concern would be the load on the pilot house roof. Can it support the compression load with out collapsing the roof? Also how far aft of center will it be?
I'm no designer just want you to do a clean safe installation. Is this a trawler with a weighted keel? Will it lay over on it's side with a good puff of wind from abeam? Just some thoughts to consider.

[maxingout]

You will need a compression post to support the pilot house from collapse.

[HoneyRyder]

Originally Posted by Diesel Bill

My biggest concern would be the load on the pilot house roof. Can it support the compression load with out collapsing the roof? Also how far aft of center will it be?
I'm no designer just want you to do a clean safe installation. Is this a trawler with a weighted keel? Will it lay over on it's side with a good puff of wind from abeam? Just some thoughts to consider.

Yes, for sure. I've already installed a very strong steel compression post, bolted and welded into the steel hull, with 30mm steel top and bottom, so no worries about that.

I have a 5 ton keel 2 metres below the waterline. The mast is only 33' and will carry 775 sq ft of sale ( cutter rig = 3 sails).

The mast will be 14' from the bow, with a mizzen further aft on the saloon roof, and both masts are designed to raise and drop with a standard A frame.

This idea is that it is a "30/70" design, i.e. 30% sail power/70% engine.

[HoneyRyder]

Originally Posted by maxingout

You will need a compression post to support the pilot house from collapse.

The compression post will take the load with absolute ease. It's made of box steel and is securely fastened at deck level, and to the hull.