Selden Boom - Excess Play in Gooseneck Clevis Pin?

[dkinzer]

I removed the boom vang today in preparation for doing some work on it and I noticed a couple of issues with the pivot joint where the boom is attached to the gooseneck. Firstly, as you can see in the attached photo, it appears that there is supposed to be a cross pin in the pivot pin to prevent it from working its way out - the Selden parts list calls the missing pin a "locking pin". The hole where the locking pin should be is wallowed out so I will either need to replace the pin, re-drill it for a new pin or make/buy a new one. I did notice that the parts list indicates that booms prior to 2003 use a clevis pin with a shoulder on it rather than the locking pin. The Selden part number for the 12 mm clevis pin and a 4mm x 11mm locking pin is 166-257-01 available from Vela Sailing Supply for $27.

Of more concern, however, is how loose the clevis pin is in the gooseneck. The hole that the 12mm pin goes through measures anywhere from 0.495" to 0.505" while the pin diameter in inches is 0.472. The short video shows how much the pin can move in the gooseneck.

Is this too much play or should I not worry about it?

 

[jssailem]

More play than I’d be comfortable with. Is the hole showing wear? The pin appears a little worn on the right side of the video image. Could the previous owner replaced the pin with one the wrong size?

 

[dLj]

Question, how does the boom attach On one side only or does it have two tabs where that pin goes through both sides of the boom connector and that piece you have in the video?

dj

 

[dkinzer]

Could the previous owner replaced the pin with one the wrong size?

I don't think so. The pin fits well in the inboard boom end piece. Further, the Selden boom parts list shows clevis pins of 8, 10, 12 and 16mm diameter. Mine is 12 mm and measures within a thousandth of that in various places across the pin.

Selden Boom Parts

I've decided to make a replacement pin of the older style with a slightly larger diameter head - 316 stainless. I don't know how the locking pin worked its way out on mine but I'd rather not have it happen again. The inboard boom casting has a recess for the head - it looks like Selden left it in and just added the slot for the locking pin to engage on the newer design.

 

[dkinzer]

Question, how does the boom attach

The inboard end of the boom has two tabs, one goes on either side of the gooseneck piece shown in the video. The 12 mm clevis pin goes through all three. The attached excerpt from the Selden boom parts PDF has a yellow oval around the inboard boom end and clevis pin (part #2). The locking pin, missing on my boat, is part #49.

 

[shemandr]

I think OP is way ahead of me on this (And maybe a lot of other topics) but I don't know if a little play is that bad. Without some play forces may build up to stress components to a breaking point. Yeah that play will create wear. But replacing a clevis pin now and then is better than a fracture of a casting. It's a case of which failure is more desirable. Just my un-informed opinion.

 

[dLj]

The inboard end of the boom has two tabs, one goes on either side of the gooseneck piece shown in the video. The 12 mm clevis pin goes through all three. The attached excerpt from the Selden boom parts PDF has a yellow oval around the inboard boom end and clevis pin (part #2). The locking pin, missing on my boat, is part #49.


View attachment 224018

With that geometry I would not be at all concerned about that amount of play.

dj

 

[JoeWhite]

Looking at the exploded diagram, there is a washer ( number 3) that must be in the indented circular area that is missing. There appears to be a clevis pin on the port side and a cutter pin on the starboard side. I would replace the pin with one that has a head on one side and on the opposite side install a wire ring instead of cutter pin and add 2 washers on each side.

 

[dkinzer]

Looking at the exploded diagram, there is a washer ( number 3) that must be in the indented circular area that is missing.

The washer (#3) is present on the starboard side where it belongs along with the cotter key. The only thing that's missing on my boom is the #49 locking pin on the port side.

My intent is to make a new clevis pin with a head on it (as was used prior to 2003). Material is on order, significantly less expensive than the Selden part (less than 1/3 the cost). However, if one doesn't have the machinery to produce such a pin from raw material the point is moot.

 

[dkinzer]

I finished making the new hinge pin (out of 316 stainless) for the boom and installed it today. I determined the diameter of the new pin by trying gage pins of various sizes until I found one that fit to my liking. I've attached a video showing the play present with a 0.492" gage pin - there is significantly less play than with the stock 12mm pin. This is 20 thousandths larger than the stock pin. I've also attached a drawing of the new pin. It is identical to the stock pin except for the presence of the head and the larger diameter pin body.

 

[shemandr]

And after watching the video I would be comfortable with that outcome.

 

[shemandr]

Oh, and nice job on that fabrication!