Mast tuning

Status
Not open for further replies.

Lynnie

.
Apr 29, 2007
23
Hunter 23.5 Lake Monroe, Bloomington Indiana
I am a new owner of a 93 Hunter 23/5 and I have questions about the information in the owners manual about tuning the mast. It looks like the manual is telling me that the top of the mast in bending aft about 1 degree at the top, and bending forward about 2 inchs at the spreaders. My previous boat was a very old Catalina 22 that was somewhat like a tank, so bending the mast is a new concept for me. Am I misreading something? Is this mast bending important since there is no back stay? And how tight do you all make the shrouds? Sounds 'pretty damn tight' in that manual. Also I read that the lower shrouds should never be tighter that the upper shrouds. But when 'everything' is tight, how can one tell which ones are tighter? Any information appreciated. Lynnie
 
D

Dennis

Yes Lynnie

follow the manual instructions, works good! In a nut shell, the mast is centered side to side with top shrouds, the forstay is adjusted to set the rake angle of the mast, and then the top and lower shrouds are tightened in a fashion which keeps the stick straight and centered and induces a slight bend in the mast. Very normal for a backstayless fractional rig. Good Luck!
 
Apr 19, 1999
1,670
Pearson Wanderer Titusville, Florida
Check the archives

I've posted on this subject several times over the past few years, albeit for the H23. The two rigs are about the same, except of course that the 23.5 has no backstay. I tune my rig without the backstay anyway. Good luck. Peter H23 "Raven"
 

Lynnie

.
Apr 29, 2007
23
Hunter 23.5 Lake Monroe, Bloomington Indiana
Archives checked

Thank you Peter for your reply. I searched the archives when I first found this website. I used search terms 'mast tuning' and 'mast tune' and didn't get any hits, so I assume I have a search term issue. I also clicked something to look at all posts and saw a really big number, 7 digits I think, so backed out of there. What search term would get me to this topic in the archives? Thanks again, Lynnie
 

Lynnie

.
Apr 29, 2007
23
Hunter 23.5 Lake Monroe, Bloomington Indiana
Straight and bent ?

Hello Dennis, So the mast is straight and bent? I guess I'll try it here in a bit. (I'm picturing the grommet things popping right outta the deck :)) And when things are that tight, how do you tell which ones are tighter? (shrouds) I didn't realize when I bought this boat that it didn't have a backstay. So if the mast falls down out on the water today I'll be sure and let you know ! Thanks for your help... Lynnie
 
R

Rick Macdonald

Loos gauge

You need to buy or borrow a Loos gauge. See link below. You need a PT1 or Model A for the H23.5. The H26 and presumably the H260 need the next size up. I like the Pro because you can attach it to the shroud and leave it there while you adjust the tension. My shrouds, and a buddy's with a H26, had slightly more then half the required tension. The factory had told me "guitar string tight". I'd played guitar for over 30 years and that didn't help me. After I got the gauge, I do know what he meant. Before tightening, the shrouds, when plucked with a thumb, would just give a "thut" and not vibrate. Now they actually vibrate some before stopping (although the turnbuckle boots interfere). That's still not accurate enough to set the tension for a first-timer. Stand at the mast and grab a lower shroud with each hand and pull both in and release. You'll see the effect the lowers have on mast bend. Most people say the lowers should be not quite as tight as the uppers. I think this is because they make a greater angle with the mast, therefore the force along the line of the shroud can be less to get the same horizontal component of force. However, it's the amount of mast bend that you'll use to set the lowers. Regardless, the end goal is to make sure the lee shroud doesn't go slack when close-hauled in a good breeze. It's the shock load of loose shrouds that's hard on the rigging. ...RickM...
 
D

Deucer

Lynnie, One thing you might or not see in passing the importance of having the forestay properly tuned before tuning the rest of the rigging. When I tuned my H260, I had to make sure the mast stepped squarely on the deck. When I first got the boat, the mast had slight gap in the front of the step with the mast up. I tightened the forestay, then tuned the rest of the rigging with a Loos gauge. Getting the forestay right is kind of hit and miss. But if I'm reading all the posts right, it should be difficult but not impossible) to attach the forestay when raising the mast. So, bottomline, follow the instructions you read here and in your instruction manual (if you don't have one, search on-line). Tune the rig, then go sailing. If the shrouds don't go slack before you have to reef, and the mast sets level on the step, then you're probably going to do OK. OBTW. Do thorough inspection of the rigging to make sure it will take the tuning. I.e., no bent shackles, cracked chainplates, broken wires in the shrouds, etc. Good Luck
 

Alan

.
Jun 2, 2004
4,174
Hunter 35.5 LI, NY
No no no....

...'getting the forestay right' is NOT hit or miss! But you do have to set the forestay length before you do anything else. Forestay length adjusts Mast Rake and ONLY mast rake. The mast rake should be set at 1% of the height. The mast height of the 23.5 is 33.5 feet or 402 inches. One percent of 402 is 4 inches. That is your mast rake. With the mast up and all shrouds loose, suspend a weight from the main halyard just above the boom. Adjust the forestay so that the halyard is suspended 4" behind the mast at boom height. That's it, no more adjustment to the forestay. Now you can proceed to center and tune the rig. A Loos gauge is cheap and makes it very easy to get right. Mast tunning is not a guessing game. Tune by the numbers and your boat will sail soooo much better. While sailing, your rig should be held securely in place with no slacking of any shrouds. If the leeward shrouds go slack your rig is definitely not tuned properly and you are inviting trouble to leave them that way. Steel shrouds should be set to about 15 to 20 percent of their breaking strength when the rig is set up correctly.
 
Status
Not open for further replies.