Cape George Cutter, righting moments

[nwdiver]

If replacing the mast, work with a reputable rigger and they will ask the right questions and have the contacts to do it right........you are talking about a race few boats finish and the cost is not inconsequential......

[Panope]

Originally Posted by GRIT

Hi Steve.

That's a very kind offer. If you wouldn't mind taking measurements and photos, I'm sure that would help.

Would you mind measuring the mast in: 1. the fore and aft direction (outside to outside), 2. atwartships (outside to outside), and 3. the thickness of the aluminum at the front, 4. and on one side? That should do it, if it's not too much trouble. The total length might come in handy too.

Is there any chance that the rigger is the original supplier of the mast to "Millie"?

I appreciate you doing this Steve. If there's something I can help you with in return, please don't hesitate to let me know.

Thank you, Steve.
Paul.

I'll swing by the riggers on Monday and try and get the measurements.

There is no chance that the current rigger is the original supplier.

Steve

[CarinaPDX]

I mentioned earlier about Lefiel (Missile) having made masts for Cape George cutters. Why not contact them and see if they still have the calculations on the 36? I remember them calculating the strengths for my mast prior to purchase and I think they did that for every mast.

Greg

[GRIT]

Originally Posted by CarinaPDX

I mentioned earlier about Lefiel (Missile) having made masts for Cape George cutters. Why not contact them and see if they still have the calculations on the 36? I remember them calculating the strengths for my mast prior to purchase and I think they did that for every mast.

Greg

I'll be calling them on Monday. We've been busy these last few days doing boat chores.

Thanks again.
Paul.

[GRIT]

Originally Posted by Panope

I'll swing by the riggers on Monday and try and get the measurements.

There is no chance that the current rigger is the original supplier.

Steve

Thanks, Steve.

Paul.

[GRIT]

It looks like Lefeil has closed their marine spar division, but we're having some luck with Ballenger spars, who has supplied some masts for the 36.

Cheers.
Paul.

[Panope]

Paul,

I was unable to gain access to MILLIE's mast for measuring. The rigging shop apparently had an issue with Covid and are fairly well locked up.

Sorry,

Steve

[GRIT]

Hi Steve.

No apology necessary. Thanks for trying. As usual, you are a great help to the forum.

I'm told there are two Naval architects, who are willing to do some calculations on her behalf. That should help too.

Cheers, and thank you for trying.

Paul.

PS. I'm on youtube watching your cobble stone anchor tests. Brilliant, as usual.

[noelex 77]

As others have said, an inclination test is not difficult and will establish the righting moment more accurately than the theoretical information from the designer.

One factor to consider with the change is that an aluminium mast has minimal inverted buoyancy (unless sealed which normally requires external halyards). The buoyancy of wooden mast makes a significant contribution to the shape of the stability curve, because while the buoyancy of a wooden mast is not high, it is a long way from the CE and COG.

This does not affect the righting moment, which is what primarily determines the strength of the mast required, but it has an impact on the seaworthiness especially for smaller yachts.

[yakimoto]

I am not sure how exact this calculation needs to be, but the RM30 calculator by Selden gives a fairly accurate measurement. May be worth giving it a try.

You can also determine RM30 by placing weights (i.e. your friends) on the rail and use a plumb bob. This method is explained well in Brian Toss' Rigger's Apprentice.

[GRIT]

That's a good point Noelex. It's something to think about, but the decision has been made, regards aluminum. Food for thought though. Thank you.

Thank you Yakimoto. I'm waiting for instruction from the owner/captain regards the next move. I think they've settled on some numbers, as I know they have a couple of quotes on masts now.

Doing stability tests is difficult for the next few months, as the boat is out in the midst of "rehab". Even if the boat was in the water, the water's quite hard at the moment. As in, ice.

There are time constraints to consider, and I'm not completely in the loop, as to where they got their numbes.

Cheers.
Paul.

[BlueRidge]

For those of you who own or have sailed a Cape George Cutter, are they stiff and tend to sail more upright, or at a large heal angle like 15-20 degrees? Thanks

[GordMay]

An interesting description of the design & construction of a Cape George Cutter:
“Anatomy Of The Cape George Cutter” ~ by Cape George Marine Works, Inc.
➥ https://capegeorgemw.pairsite.com/wp...rochure3-1.pdf

[Benz]

Originally Posted by BlueRidge

For those of you who own or have sailed a Cape George Cutter, are they stiff and tend to sail more upright, or at a large heal angle like 15-20 degrees? Thanks

Like many boats of that design, my Cape George tends to heel easily at first, but resist it more as the rail nears the water. 10 degrees is a normal heel angle for decent speed upwind; there's no real advantage to burying the rail, since at that point a sail reduction will keep the speed up well with less drag.
That said, my CG31 is gaff rigged, so I can carry more sail area in higher winds with less heeling moment than the ones with jib-headed mains.