Spinnaker Pole Rigging - Strength Required?

[Slowboat35]

How much load is the uphaul and downhaul required to take? Is it much? Do the end-to-end pole pennants really need to be wire? Is a stanchion mount strong enough to secure a downhaul or does it need something beefier? 35 ft yacht, 4m pole. Light-ish spinny (to 15Kts app) prob 90sq.m

 

[Rappey]

And one more to add to the list, why do some poles have pennants joining in the centre for Uphaul whereas some attach at the outer end?

 

[RJJ]

And one more to add to the list, why do some poles have pennants joining in the centre for Uphaul whereas some attach at the outer end?

if you rig the pole to dip, then it's slightly advantageous to have up/downhaul at the outer end, for better leverage and control.

If you end-for-end or "through-pole" then you have to have a setup that works for both ends. You can still dip the pole with this arrangement.

 

[Deleted member 36384]

How much load is the uphaul and downhaul required to take? Is it much? Do the end-to-end pole pennants really need to be wire? Is a stanchion mount strong enough to secure a downhaul or does it need something beefier? 35 ft yacht, 4m pole. Light-ish spinny (to 15Kts app) prob 90sq.m

1. Uphaul sees high loads that are caused by downhaul tension from the guy in normal use. Otherwise it is just pole weight.
2. Downhaul high loads are when reaching and the downhaul contributes more to keeping the spinnaker tack at the correct height as the guy angle becomes more obtuse and may not provide all the force that is needed. When the spinnaker collapses and fills thats when you see the downhaul take a hit as the tack tries to rise suddenly.
3. The end to end pennants are wire as it offers strength and less stretch for a much smaller diameter for a bridle that is also at an obtuse angle and therefore high stress. Other materials could be used equal to the breaking strain of the wire.
4. For end to end, it would be better if the downhaul was on the centre line. Stanchion bases may not be strong enough and a dedicated eyebolt would be better. For light wind use, depending on the stanchion base, probably okay, but a guts that causes excessive loading could cause issues. However, if you only have a bridle for the uphaul and the downhaul is clipped to the pole end, then you may have to gybe the downhaul as well.

Its all possible if you have worked out how to do it on your own boat's arrangements and then tried it to see if it works.

 

[William_H]

In my experience it is the down haul that has the greatest load when reaching. A down haul to the pole end has much more power (purchase) than centre attachment. It follows that fro centre attach you need a very robust central deck attach and a pulley purchase. Whereas at the end the loads are much easier but of course you need to deck attach on each gunwhale. The down haul can then be used to assist in pulling the pole off the forestay.
The size of the boat you have is on the cusp of end for end pole gybing or dip pole gybing.
I a have sailed on 36ft purely racing yacht where end for end is used. The down haul is in the form of line from a sheave or ring which runs on the brace. Going down to a point on the gunwhale about half way along the foredeck. So to haul down the pole you haul down the brace. In a gybe you release the haul down and pull down the other side as brace becomes sheet. Fairly simple and easy to use. Some gymnastics on the fore deck required. The topping lift takes the weight of the pole while in transit.
On the other hand the dip pole arrangement is far more secure in action. The pole attach at the mast is raised so that pole can dip through inside the forestay.
The spinnacker has both sheet and brace on each side. So in gybing you can take the pressure on the sheets when running square. Release the tension on the brace so that pole can be swung down to the centre where braces are swapped over. New brace is pulled so pole goes out ready to go harder onto the wind if necessary. Brace is sheeted from a point well forward so that it tends to take down haul loads itself. ol'will

 

[TernVI]

How much load on the pole-up and pole-down depends hugely on where the guy is attached to the boat.

On a small boat it may be worth considering a slightly bigger section pole in carbon or something, if it allows nice easy to use end for end gybing.
I'm not a fan of up/down lines on bridles to the pole, it's usually easier to use a single ended pole, if the twinning lines are used effectively, or you have separate sheet and guy/'brace' each side.