Boom connection to mast

[Cecil A]

I'm a new owner and sailor. Please forgive my use of the wrong terms. I have a Sirius 21. I'm not sure I have the original or correct boom mount (gooseneck). Where on the mast should the boom be connected, above or below the slot, and what would be the right distance from the bottom of the mast to the boom. What holds the boom in the right hight. Currently I am putting the boom slug in the slot and let it follow the sail up the mast track. The only thing I have to hold the boom down is the vang. I am ordering a new mainsail so an accurate measurement is important. Any advice will be a greatly appreciated. Any pictures will be very helpful also.
Cecil A

 

[Simon Sexton]

@Cecil A ,

Good morning! I have seen this problem many times with smaller boats, and it is often either one of two things: The mains'l is the wrong size (too small), or a part is missing. This part that often is overlooked is a screw-tight stopper that keeps the boom from being pulled up high enough to be removed from the mast track; thus, it is placed just above the gooseneck a few inches beneath the slug entrance in the track. Try that, and if the sail doesn't reach topmast, it's time for a refit! I hope this helps!

God Bless,
S.S.​

 

[shemandr]

A picture would be a big help. There might not be a "Correct" height for the boom. It is sometimes adjustable and can be a sail control analogous to a cunningham.
You could jury rig this by using line connected to the deck or lower mast, with a block or two, to pull the boom down and hold it there while sailing. The line should be similar to the halyard.
You can rig a topping lift from the backstay, if you have one, or the top of the mast to hold the boom up while the mainsail is down.
I wouldn't order a new sail until you work out the gooseneck thing.

 

[Dave Groshong]

The mainsail holds the boom up when it is hoisted, a topping lift or boomkicker holds it up when the mainsail is down. The boom should connect below the slot. The hoist length of the mainsail must be correct to maintain a 90 degree position when the sail is full hoisted.

 

[dsims]

The boom connects to the mast just below the slot for the main. I'll try to get pictures of mine this week to show how it looks. The rear of the boom is held up by a topping lift.

 

[Cecil A]

Thanks for the comments so far. Your guidance is pushing me in the right direction. I'm not concerned about the aft end of the boom. My topping lift may need to be adjusted but that is a later issue. My current problem is getting a good luff measurement to send to the sail maker. I will try to get pictures when I raise the mast again, but if anyone can get pictures of their boat, that will be most helpful.

 

[Cecil A]

Thanks DSims. Pictures of your setup will be great.

 

[MitchK]

My CM25 has a similar gooseneck arrangement. I position a slug stopper below the slot, then insert the gooseneck slide portion. There is a loop on the bottom of the gooseneck that has a line attached. The line goes to a cleat attached to the mast several inched below the boom. The slide stop keeps the gooseneck from dropping too low, and the line connected to the gooseneck keeps the gooseneck from sliding up when you raise the sail.

 

[Cecil A]

 

[Cecil A]

Here are some pics of my boat. I can't get on the water to get sailing photos but I hope these will show my problem. In the pic of the whole boat and the first closeup the gooseneck slug is at the bottom of the opening. There is nothing holding the boom to the mast. It can fall right out. If I put it below the cotter pin it can side down to the deck. That's not good
In the last pic it shows the gooseneck above the opening with a cotter pin holding the boom up in the slot. In this configuration the boom vang holds the boom down. This is the way I have been sailing the boat. Am I missing parts or what am I not understanding?
It's an old boat that has been sailing for many years before I bought it. I'm not looking to reinvent sailing, nor redesign the boat. I'm just wanting to understand how it was intended to be put together.

 

[Cecil A]

@Cecil A ,

Good morning! I have seen this problem many times with smaller boats, and it is often either one of two things: The mains'l is the wrong size (too small), or a part is missing. This part that often is overlooked is a screw-tight stopper that keeps the boom from being pulled up high enough to be removed from the mast track; thus, it is placed just above the gooseneck a few inches beneath the slug entrance in the track. Try that, and if the sail doesn't reach topmast, it's time for a refit! I hope this helps!

God Bless,
S.S.​

What is the screw-tight stopper. As for the refit, I am ordering a new sail but it's important to understand where it should fit so I can get an accurate measurement. It does look like my current sail is the original

 

[Simon Sexton]

What is the screw-tight stopper. As for the refit, I am ordering a new sail but it's important to understand where it should fit so I can get an accurate measurement. It does look like my current sail is the original

It's basically a nut that slides down the track. When you get it to where you want it, you screw it tight so it clamps down on the track, preventing the boom from moving out of place.