Thank you for your help Ash. What I was trying to describe was adding a short sleeve to the bottom of the actual mast. Epoxied interior or exterior or both, in an attempt to increase the surface area that the pin bears on.

What you are describing depends on just the wall thickness of the pole bearing on the pin, if I understand it correctly.

My greatest concern being the foremast resisting the up and down pounding at the mast step connection point, in heavy weather. I am not so concerned about the step design as discussed on the site. It is the mast wall thickness, strength, work hardening, and the pin or fasteners that concerns me.

It is my understanding that the work hardening of aluminum happens when the material begins to flex back and forth. That is not the case as I understand it, when a pole deflects or flexes over its length. The metal needs to deform in its movement. So it is logical to assume the prevention of work hardening is to increase the resistance to flex that deforms, at the point of attachment.

So how do you increase the rigidity and strength where the pole is fastened to the mast step without welding?

What about modern adhesives, epoxies etc? Aren't they far stronger than any fastener? Do you think a properly sized aluminum sleeve, attached at the bottom foot of the mast, internal or external, epoxied in place with thickened epoxy would strengthen the wall at the mast step connection?

Hi Ben,

Street lights are loaded only by their own windage, once you stick a sail on it the loadings are much higher, and suffer from acceleration/ deceleration when waves throw the hull around i suspect a welded end flange couldn't cope but would work harden and fail, supporting it over a 10% bury must apply the forces to the whole pole more evenly.

When you get a big fish on your fishing rod i'll bet you space your hands out?

Cheers 

Ash

I have spent a great deal of time researching tapered aluminum light poles.

The poles have been engineered and designed to free stand with the only anchor point being the four bolt base plate, that the pole is welded into. The poles are engineered to withstand varying amounts of wind force, with different mast arms mounted at the top. Some are even hurricane rated.

Some poles have oval access ports near the base. Inside the pole, there is a reinforcement plate welded in around the oval access. It also has a cover.

If the pole has been engineered and rated by someone much more qualified than I am, to withstand high wind loads, with no other support than the base plate fasteners, with the access port in the pole at the base, why would I assume this is a weak point that is unusable in a marine mast application?

I understand the boat is almost in constant motion. But how would this load differ from the cyclic wind loading of a stationary mounted light pole?

If welding on an aluminum mast causes strength issues with cracks, as I have read on the site,  why would the rated poles have welded bases and welded access covers?

I have looked at hundreds of retired, salvaged and damaged light poles. Many poles had been knocked down by vehicles at speed. Inspection of highly damaged poles revealed no weld failures. I observed no cracks or weakened areas around the welds. I did not see deformation of the pole in the oval access areas of the damaged poles.

I live in an area which was ground zero for hurricane Sandy. I see forty foot poles (12m) with oval access holes, mounted only by the base plate, that survived the storm even with long mast arms and light fixtures mounted at the top.

I am assuming that the fulcrum of the mast partners exerts different loading (shear?) of the mast base than it was designed for (compression and tension?), making the oval access area a weakness.

If the pole was engineered to free stand from its mounting plate, maybe it would be better to build a mounting post from the hull step to the partners. Integrally built and robustly supported, to then surface mount the light pole as designed and engineered.

This may not be possible as they are usually mounted to reinforced concrete. Designing a deck partners/post/keel step configuration strong enough may be an issue.

Maybe we use the through deck installation because it is just easier. 

Selection of a light pole is made more difficult because of the "usable length available" due to the access and light mast mounting holes in used poles that are available. It is further compounded by the length lost from the bury.

This post is directed at the use of used or salvaged poles. If you choose to spend 2,800 for a new pole, you can order it with no holes, but still need to account for extra length for bury.

These are all just thoughts and observations. Welders, engineers, boat builders, anyone with any experience in this area please comment. Thanks.