I broke my boom!! What is this part called and how to attach it?

ProDave

Well-known member
Joined
5 Sep 2010
Messages
15,170
Location
Alness / Black Isle Northern Scottish Highlands.
Visit site
Sailing today, with a reef in the main sail, a part broke off the boom. It's the fitting on top of the aft end of the boom, onto which the topping lift and the reefing line was attached. I now know that should only have been used for the topping lift, and the reefing line should have been secured to a different fitting. (the joys of a second hand boat that didn't have the best of previous owners)

The reefing line is now attached to where it should be, and topping lift secured temporarily but now need to make a permanent repair.

I first need to find the correct name for the now missing part, It's a U shaped SS bit of metal that I would describe as a "saddle" (as in it looks like an electrical conduit saddle fitting) No doubt in marine terms, it has a completely different name.

Of course I don't have a picture of the missing part. An image search has found this picture:

dscn0817.jpg


The part I am talking about is riveted onto the side of the boom in the above picture. Ours was riveted onto the top of the boom. I need to know the correct name of that part so we can buy a new one.

The rivets pulled out of the mast and the part is lost. To replace it the choices seem to be drill out and use larger rivets than before, or since it is near the aft end of the boom we recon we can get in there to attach a washer and nut, to nut and bolt the replacement on. Thoughts on that please?
 

rogerthebodger

Well-known member
Joined
3 Nov 2001
Messages
12,481
Visit site
Outhaul turning block

OR

a reeving line turning block

I have one on each side of my boom for first and second reeving lines
 

Tranona

Well-known member
Joined
10 Nov 2007
Messages
40,927
Visit site
Pretty standard item from any chandlers or rigger. suggest attaching it in a different location. You will need a substantial riveter so probably better to get a rigger to do it for you if you can.
 

ProDave

Well-known member
Joined
5 Sep 2010
Messages
15,170
Location
Alness / Black Isle Northern Scottish Highlands.
Visit site
Pretty standard item from any chandlers or rigger. suggest attaching it in a different location. You will need a substantial riveter so probably better to get a rigger to do it for you if you can.
Yes but what is it called?

Used correctly as just the topping lift it is not subject to much load, it was overloaded in this case because the reefing line was tied there, instead of a different more substantial fitting.

What about my idea of nut and bolting the replacement on? this is supposed to be the place for practical boat owners to fix their own boats is it not rather than paying someone to put a couple of rivets in?
 

Daydream believer

Well-known member
Joined
6 Oct 2012
Messages
19,463
Location
Southminster, essex
Visit site
Lacing eyes here
I would put it on the underside of the boom (is there one there already that you can use?) & splice, or whip, a loop on the end of the topping lift. This will take the load & the lacing eye will then only hold it in place, thus not straining any pop rivets or other type of fixing that you use.
 
Last edited:

Tranona

Well-known member
Joined
10 Nov 2007
Messages
40,927
Visit site
Yes but what is it called?

Used correctly as just the topping lift it is not subject to much load, it was overloaded in this case because the reefing line was tied there, instead of a different more substantial fitting.

What about my idea of nut and bolting the replacement on? this is supposed to be the place for practical boat owners to fix their own boats is it not rather than paying someone to put a couple of rivets in?
force4.co.uk/item/Seasure/Lge-Deck-Eye-2pk/PBA

This is one type, also called lacing eyes. Simple things but attaching to a boom is not easy as normally you don't have access inside for a nut and bolt so the usual fixing method is a pop rivet and the size you need requires a good riveter. If you have access to that then jobs easy, making sure you insulate it from the aluminium. I expect yours has failed because of corrosion so you may not be ble to use the same holes. If your boom wall is thick enough you might be able to drill and tap, or even use a selftapper, but neither of these are as good as a rivet.
 

William_H

Well-known member
Joined
28 Jul 2003
Messages
13,678
Location
West Australia
Visit site
I would call the fitting a saddle. Yes if you can replace the old one with similar size with nuts and bolts. I might suggest the saddle be fitted on top of the boom, off to one side of reefing line exit box. This to possibly avert the saddle hitting a person's head. (of course there is that hulking greeat sheeve box on side anyway) Possibly not a concern on a bigger boat. Op will proably have difficulties removing the end cap of the boom due to corrosion. In which case it must be rivets. Not easy to find and fix bigger rivets. Need to use stainless steel or monel with plenty of duralac or similar in hole to avert corrosion. could also try threaded screw into tapped hole in ali. ol'will
 

Alex_Blackwood

Well-known member
Joined
19 May 2003
Messages
1,604
Location
Fareham
Visit site
I would call the fitting a saddle. Yes if you can replace the old one with similar size with nuts and bolts. I might suggest the saddle be fitted on top of the boom, off to one side of reefing line exit box. This to possibly avert the saddle hitting a person's head. (of course there is that hulking greeat sheeve box on side anyway) Possibly not a concern on a bigger boat. Op will proably have difficulties removing the end cap of the boom due to corrosion. In which case it must be rivets. Not easy to find and fix bigger rivets. Need to use stainless steel or monel with plenty of duralac or similar in hole to avert corrosion. could also try threaded screw into tapped hole in ali. ol'will
What about rivet nuts??
 

ProDave

Well-known member
Joined
5 Sep 2010
Messages
15,170
Location
Alness / Black Isle Northern Scottish Highlands.
Visit site
The reason it failed is this fitting is supposed to only have been for the relatively light load of the topping lift, but wrongly the end of the reefing line was also tied to it imposing a much greater load. the reefing line has now been moved back to it's correct, more substantial place. So it is just reinstating the fixing for the topping lift.

The mast end in this case is open so we have access for nut and bolting without taking anything apart so I think that is what we will do.
 

dunedin

Well-known member
Joined
3 Feb 2004
Messages
12,639
Location
Boat (over winters in) the Clyde
Visit site
Similar to Daydream’s suggestion, I would suggest typing a few loops of strong but thin rope round the boom with a loop above to attach the topping lift to. There there is no strain on any pop rivets or bolts.
Done tight enough the exiting lacing eye/rivet heads should keep it on, but if worried a light secondary lashing to the pulley would do the trick.
Not only the strongest solution but also near zero cost and no difficult large rivets to fit.
 

arcot

Member
Joined
25 Sep 2020
Messages
109
Visit site
Eye bolt with large washers both sides thru bolted from one side of boom to other side using 8 mm ss bolt
 

penfold

Well-known member
Joined
25 Aug 2003
Messages
7,732
Location
On the Clyde
Visit site
Lacing eyes here
I would put it on the underside of the boom (is there one there already that you can use?) & splice, or whip, a loop on the end of the topping lift. This will take the load & the lacing eye will then only hold it in place, thus not straining any pop rivets or other type of fixing that you use.
There's already one there, no need to fit one.
 
Top