More mast

All my fabrication on the mast is complete and it is ready to haul to the boat yard. That being said, this simple dinghy lifting mast turned out to be quite a bit more work than I  had figured, and I for those who know what Im going to say next means, I used a large bottle of Argon for the welding. I would have never guessed a large Argon bottle would have been consumed, but it was.

Of course, having never done this type of project before didnt help with me getting finished in a reasonable amount of time, nor did my lack of putting a pencil to paper for some design work help much either. The mast step is already welded to the boat, and is comprised of two heavily gusseted pieces of 1/2" stainless plate welded into the heavily reinforced roof framing. The two plates have bores through them that the mast will pin in to allowing it to be easily laid down. The upper pin in the mast will bear the load, and the lower pin will be for locking it in place. In order for the mast to be able to pivot, I laid it out so that there is 1.5" of free space between the bottom of the mast and the step base. Once the mast is stepped and stayed, solid blocking will be wedged between the bottom of the mast and the step base. Because the bushings are going to be TIG welded in to the mast, I had to do a bit of compensating to allow for weld distortion. I decided to bore the bushings .006 over the pin diameter, and as luck would have it, that turned out to be the right amount. The fit is good with no tight spots and every so slight end play. When the pin engages both bushings, there is no side to side play. The lower pin used for locking the mast in place has no bushings welded in place.

The blocking should be 1.5" if I measured once and cut twice correctly.... or is it measure twice and cut once? Because the upper pin is going to bear the load, I decided to weld in heavy bushings to spread carry the load in the masts along with a more tolerant fit. Each bushing is two inches long, with 3/8" wall thickness ( the mast pin is 1.25" SS ).

In order to get the install alignment on the mast step perfect, I decided Id have to weld bushings in the step when  we install the mast. To build those bushings I used some  two inch aquamet prop shaft from the scrap pile at Washington Marine. Gregg at Washington let me pick some scrap pieces for my pins and bushings, and it was much appreciated.  Stainless steel is really nice material to work with on the lathe, and machines great.

Instead of butt welding the shroud and stay plates to the mast, I thought it better to use solid plates that ran through the mast. Eventually a steadying sail will be fit on the mast, along with a paravane rig, so I wanted the plate connection as stout as possible. The plates are 1/2" material, and because I dont really know the final configuration, I drilled what I thought was enough holes in each plate for possible future use. Drilling these holes 1.30" on center allows for shackles to fit next to each other.

A pad was framed at the top of the mast for the radar array along with a spreader bar that will hold work lights, a masthead/navigation light, weather center, and blocks for flags. The spreader bar is large enough antennas if we need.  I bored a two inch hole above the spreader bar for wires to exit the mast and fasten to the spreader bar.

The 4" boom will have an electric winch on it for hoisting a load, and the mast will have another electric winch on it for lifting the boom. The plan is to hoist the load with the boom winch, then raise the boom with the mast winch to get the load over the rail and on to the roof. Well control the side to sided with tag lines. The winches have remote controls, so that should make things a little easier to operate. I"m not 100% sure, but to power the winches, Im going to have a battery on the roof with a small dedicated charger in the wheel house, or possibly a small solar panel to keep the winch battery fresh. Either way, the battery will be in a weather tight box along with the winch fuses and solenoids.  All the winch brackets are in place along with test fitting the winches.
 
The cables used for the mast are 1/4" galvanized. All the shackles and turnbuckles are also galvanized. Because Im always on a budget, I used hour glass type swage fittings to make up my cables. These types of fittings are not as nice as the single pass stainless swage fittings used on sailboat rigging, but theyre for sure in my budget and look much better than cable clamps. I did use stainless steel on the thimbles since this point will see some abrasion. Years down the road when I start doing maintenance and repairs, I hope to upgrade to all stainless.

The next step will be to fit the mast to the step by welding in the step bushings with the mast in place. Once thats complete, well stand her up and be on the right side of having this job close to complete. Im pretty pumped about having a way to hoist loads to the roof. This is going to be big time handy for getting bikes, kayaks, and of course our tender to the roof. I know Ill also be  using this to hoist the welder for the handrail job along with hoisting the handrails. I hear of cruisers loosing tenders to theft because they have too much difficulty getting the gear out of the water and leave it out overnight. I"m hoping our rig is going to make our lives easier.

Cheers

       

Related Posts by Categories