Association Forum - CG of C25 SR mast

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

CG of C25 SR mast

New Topic

Topic Locked

Printer Friendly

Author

Topic

Chemist
Deckhand

Member Avatar

USA
16 Posts

Initially Posted - 06/27/2005 : 14:46:35

Does anyone know whether the center of gravity of a C25 SR mast is above or below the spreaders? If it is below, my task of mast raising is simplified. I should know, but I haven't really been concerned before now (new equipment for raising the mast is available).

Thanks

Bob Imes

C25 #1544 sk, sr, "Prime Time", still on the hard

Edited by - on

Leon Sisson
Master Marine Consultant

Members Avatar

USA
1893 Posts

Response Posted - 06/27/2005 : 16:18:35

The CG of either C-25 mast is pretty much right at the spreaders, give or take just a few inches. Spreader bases are exactly mid-extrusion. Everything inside the mast weighs the same per foot above or below spreaders. The masthead fitting, antenna, anchor light, etc. are about offset by lower shrouds, lines coiled up at the base, etc. This is why using a loop of line slid up the mast to the spreader bases of a simple single spreader rig works so well when using a mast stepping crane.

-- Leon Sisson

Edited by - on

Dave Laux
Captain

Members Avatar

318 Posts

Response Posted - 06/27/2005 : 22:32:06

The CG is somewhat dependent on whether the lower ends of the shrouds are stopped off to the bottom of the mast. I would maintain a good grip on the mast bottom in any case. Dave

Edited by - on

stampeder
Master Marine Consultant

Members Avatar

1608 Posts

Response Posted - 06/27/2005 : 22:46:43

First time I raised my mast, I used a dock crane, with a loose loop under the spreaders, we raised the mast and found it quite easy to maneuver the base into the step.
I've raised and lowered the mast about half a dozen times in the past year - the biggest and most important aspect has always been keeping the lines and rigging free of tangles and snags.

Edited by - on

lcharlot
Master Marine Consultant

Members Avatar

Antigua and Barbuda
1301 Posts

Response Posted - 06/30/2005 : 23:40:27

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Leon Sisson
 The CG of either C-25 mast is pretty much right at the spreaders,
<hr height="1" noshade id="quote"></blockquote id="quote">

The above statement is only true if your boat does not have roller furling. If you add a Crusing Design FF4 furler, the weight of the luff extrusion will move the balance point several inches above the spreaders - I know this from personal experience. This can give you a nasty surprise when doing a mast raising evolution, in that a mast that should be perfectly balanced on the mast crutch will, because of the furler, be top heavy, casuing the butt of the mast to suddenly jump up and try to whack you in the face when you pull the pin out of the tabernackle. This problem is especially severe in Tall Rigs, as the "nominal C.G." at the spreaders is about 12" aft of the transom when the mast is down, due to he Tall Rig being 30' instead of 28'. With the Tall Rig, it is pretty much a necessesity to build a special mast crutch that hangs off of the transom, far enough to catch the mast above the spreaders, instead of sitting on the cockpit floor.

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.