[Rhodes22-list] Rebedding Mast Raising Gin Pole Fitting On CabinRoof

Wed May 12 10:51:50 EDT 2004

Jay:

	The first thing I noticed was that Roger changed the subject line.
In my reference to the Epoxy Works web site there are two articles related
to the subject under discussion in the current publication:

1.  Bonding fasteners in high-density urethane foam

2.  WEST SYSTEMR epoxy for fiberglass boat repair

See:  http://westsystem.com/ewmag/

Again, I would also reinforce the core material between the cabin roof and
interior ceiling.

With my new super speed web access, it now takes about 20 minutes for out
emails to post, while I can access the internet in 2715kbs/ 239kbs, go
figure.           

-----Original Message-----
From: rhodes22-list-bounces at rhodes22.org
[mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of Roger Pihlaja
Sent: Wednesday, May 12, 2004 8:35 AM
To: The Rhodes 22 mail list
Subject: [Rhodes22-list] Rebedding Mast Raising Gin Pole Fitting On
CabinRoof

Jay,

A couple of years ago, I retrofitted the GBI single handed mast raising
setup.  The photo that was enclosed in the earlier post on this subject
looks like my gin pole setup.  So, I presume the mounting fitting on the
cabin roof is the same.  I thru-bolted the two bolts on the cabin roof.  Use
1/4 - 20UNC SS flat head screws, 5/16 inch ID X 1-1/2 inch OD SS fender
washers, and 1/4 - 20UNC SS barrel nuts.  Look on pp. 591 - 592 of the West
Marine Master Catalog, 2004 for these pieces/parts.  The stainless steel
fender washers & barrel nuts will give you a nice polished fastener that
will be very strong, look good, will be accessible for maintenence, and will
not be a head banger on the roof of the cabin in the head area.

When stepping the mast, the mounting fitting under the gin pole is under a
combination of compression loading and shear loading.  The relative
proportions of shear load & compression load change as the angle of the mast
changes.  Compression loading is the dominant force at the beginning of the
lift when the mast angle is low & the gin pole is nearly vertical, with
shear loading steadily increasing as the mast gets more vertical & the gin
pole lays down onto the foredeck.   The structure of the cabin roof resists
the compression load.  However, the only structural elements resisting the
shear load are the two 1/4 - 20UNC bolts.  MJM's hypothesis re the screw
threads being stripped on the bolt that simply turns is probably correct.
As such, the ability of that bolt to resist shear loading must be considered
suspect & putting all the shear load on the single remaining bolt is a
dangerous proposition.  The consequences of the bolts failing under shear
load would be that the base of the gin pole would come free under load.  The
gin pole and the mast would go shooting every which way & the forces
involved are enormous!  Since there would very likely be someone standing
beside the gin pole cranking the winch handle, that person would almost
certainly be injured.

Please do not attempt to use your gin pole until you get this problem fixed!

Roger Pihlaja
S/V Dynamic Equilibrium

----- Original Message -----
From: "Jay Friedland" <jsail1 at verizon.net>
To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
Sent: Wednesday, May 12, 2004 7:03 AM
Subject: Re: [Rhodes22-list] Mast Crutch

> Michael-
> Thanks for the response. As i have the tap, etc., that's my best
> choice. Is Marine Tex a reasonable epoxy for this? Also, how much
> should I oversize hole for this? thanks again.
>
> Jay
>
> On May 12, 2004, at 12:02 AM, Michael Meltzer wrote:
>
> > you have a problem, they drill and tap into the fiberglass, if the
> > screw is turning it is doing nothing, worst yet the block could
> > give way during a lift, that would be no fun. the force for the most
> > part are in sheer but their is enough lifting force on some
> > angles. SO... enlarge the hole some, fill with thicken epoxy, drill
> > and retap, and use some silicon to rebed. Second method is to
> > thought drill into the cabin top, and bolt with a fender washer and
> > bedding, but that is ugly but cheaper that buying
> > countersinks(to cut the glass so it does not crack) and taping tools.
> >
> > MJM
> >
> >
> > ----- Original Message -----
> > From: "Jay Friedland" <jsail1 at verizon.net>
> > To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
> > Sent: Tuesday, May 11, 2004 10:44 PM
> > Subject: Re: [Rhodes22-list] Mast Crutch
> >
> >
> >> Ed or others,
> >> Would you know how to tighten screw on mounting block on the cabin
> >> top?
> >> One is actually tight, the other turns with nothing binding. Is there
> >> a
> >> nut behind it, and the liner covers all from below. It seems it only
> >> holds the ginpole in place, but not sure how much load is on it.
> >>
> >> Jay
> >>
> >>
> >> On May 11, 2004, at 8:18 PM, ed kroposki wrote:
> >>
> >>> Todd,
> >>> I know you work a lot, but sometimes just look at the R22 web site.
> >>> The picture shows the old system, but the mounting to the cabin top
> >>> is
> >>> the
> >>> same. Just look around:
> >>>
> >>> http://www.rhodes22.org/rhodes/pics/crane2.jpg
> >>>
> >>> Ed K
> >>>
> >>> -----Original Message-----
> >>> From: rhodes22-list-bounces at rhodes22.org
> >>> [mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of Todd Tavares
> >>> Sent: Tuesday, May 11, 2004 8:05 PM
> >>> To: The Rhodes 22 mail list
> >>> Subject: Re: [Rhodes22-list] Mast Crutch
> >>>
> >>> Slim,
> >>>
> >>>      When you do get the camera out, take a couple of pics for me
> >>> too.
> >>>  I am
> >>> interested how the crane pole mates up with and sets on the block
> >>> mounted on
> >>> the cabin top.
> >>>
> >>> Todd
> >>>
> >>>
> >>>
> >>> ----- Original Message -----
> >>> From: Steve Alm <salm at mn.rr.com>
> >>> Date: Tue, 11 May 2004 13:59:24 -0500
> >>> To: rhodes22-list at rhodes22.org
> >>> Subject: [Rhodes22-list] Mast Crutch
> >>>
> >>>> John,
> >>>> I wish I had a better picture of my mast crutch for you--this one
> >>>> doesn't show too much detail--but this is the GB design for lowering
> >>>> the mast to the stern.  At the bottom, the two aluminum tubes are
> >>>> attached to plastic (plywood could be used) pieces that are notched
> >>>> to
> >>>> fit over the transom.  The transom bears the weight--not the rail.
> >>>> There is a horizontal piece of the same material with a cutout that
> >>>> fits over the stern rail and stern light.  This adds stability.
> >>>> Then
> >>>> there are two lines coming down from the top that tie to the stern
> >>>> cleats which add even more stability.  If I get a chance, I'll take
> >>>> more pixs and post them.
> >>>>
> >>>> Hope this helps,
> >>>> Slim
> >>>>
> >>>>
> >>>
> >>>>
> >>>> Name: PA15401239907.jpg Type: image/jpeg Size: 244755 bytes Desc:
> >>>> not
> >>> available
> >>>> Url:
> >>> http://www.rhodes22.org/pipermail/rhodes22-list/attch/200405/11/
> >>> PA1540123990
> >>> 7.jpg
> >>>
> >>>>
> >>>>
> >>>> Trailer-2
> >>>>
> >>>>
> >>>>
> >>>
> >>>>
> >>>> __________________________________________________
> >>> Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
> >>> --
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> >>>
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> >>>
> >>>
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> >>>
> >>
> >> __________________________________________________
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> >>
> >
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> >
>
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