lowers

[philipcosson]

Hi,

How strong do lowers have to be and how much tension? I have steel lower shrouds on an 8:1 normal rope pully system - I notice some boats have dynema lowers.

One of the brass bal bearing blocks at the mast step has been pulled apart by the tension. I have fixed it, but feel this is probably too much force.

The mast is secured quite low down by the spaceframe (3-5 inches bellow normal deck level))

Regards

Philip

N3253

[Mikey C]

Some of the spaceframe Baggy's had the masts sheathed by another section of mast over the top (3217 springs to mind). If your mast is like this I would reccomend ditching the lowers altogether and just relying on the screw adjuster at deck level...

Lowers are probably the highest loaded control you can have on a 12 as they are working in completely the wrong plane to the direction of travel...

[Lukepiewalker]

3253 is an exception. It has a 'normal' mast ram instead of the screw and doesn't have a sheath on the mast. You could probably swap the wire for an appropriate modern rope.

[Steve S (Guest)]

N3253 is similar to the Baggy 2 I had. The low spaceframe does mean very large loads are required to effect any bend further up the mast if you are just using a ram or screw at the space frame. The space frame is restraining the mast sideways, but the distance from the gooseneck to spaceframe is greater than the equivalent distance on a conventional decked boat and hence much greater side force and bending moment are imposed. If your mast is not sleeved internally I would be surprised if it withstands the first decent blow you take it out in. The lowers need to be attached up near the gooseneck for best effect.The load in my experience is greater than the breaking load of 2mm wire but less than that of 2.5mm wire.

Not sure what Mikey C is saying about the load directions being wrong. Offwind where the side loads are high from the boom at the gooseneck the lowers are doing a great job, particularly on the leeward side.

Regards,

Steve
N3436