Re: Lateen rig on p15

Gordon (hlg@pacbell.net)
Mon, 28 Dec 1998 11:07:42 -0800


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West Wight Potter Website at URL
http://www.lesbois.com/wwpotter/
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>Does the Sunfish rig fit on the standard Potter? What is the risk of
>lateen rig being unstayed compared to standard Potter stayed sloop rig?
>If I were sailing Bahamas in P15 with passages between islands up to 30
>miles which rig to you think would provide the best combination of
>simplicity and safety?
>
>
>Dan Miller
>a019507t@bcfreenet.seflin.lib.fl.us

Dan-

The mast of the lateen rig has to be about a foot further forward than the
mast step of the standard Potter 15 in order to have the center of effort
properly located for a balanced helm. That requires installing a sleeve
that the Sunfish mast can drop into, usually an aluminum tube with an ID
that fits the OD of the mast snugly.

The risk of the unstayed rig will be proportional to how well you engineer
and construct the mast sleeve. With no stays the sleeve has to carry all
the wind load of the sail. Steve Barnes and I have sleeves that extend to
the cabin sole and are solidly secured there. He used a "spider" casting of
the kind used for fishing deck chairs. I used a boat trailer roller
bracket. We both used a bolt in a hole drilled through the tube to limit
how far the mast is buried in the tube. The base of the mast sits on the
bolt. The mast should be free to rotate.

The sleeve requires a hole in the cabintop of course, and the cabintop
provides the lateral support of the mast. Steve has found a simple hole in
the cabintop was sufficient, but on my first generation Potter, which is
constructed differently, I felt it necessary to add a plywood doubler to
the inside of the cabintop so I would be more confident that the leverage
of the mast would not tear open the cabintop . It has held up well, but
recently, after a gusty sail, I found hairline cracks in the gelcoat around
the top edge of my cabintop, indicating the whole cabin is flexing, so I
plan to add a shelf that will transmit the mast load to the forward and
side decks, greatly reducing the load on the cabintop. The shelf will add
useful storage space also but will add more weight. Since my first
generation Potter doesn't have an internal liner, it is much easier to work
on.

Lars Mulford was the first of our e-mail group to have a lateen rig Potter,
and his was built new to order by International Marine, but it was not well
conceived or constructed and started to come apart. The dealer in Annapolis
carefully rebuilt it, making the sleeve very substantial, and Lars
subsequently sailed it in near gale conditions and was totally satisified
with it. All three lateen rigs have the mast hole located at the forward
edge of the cabintop, which resulted in a balanced helm.

The first known lateen rigged Potter was built for Larry Brown by HMS
Marine and is described in his book, _Frugal Yachting_.. He had reefing on
his, which he describes in the book. I haven't added reefing to mine yet,
but I certainly would before I attempted 30 mile passages. My own longest
passage was 20 miles across Monterey Bay, but that was long ago and with my
original gunter rig. That took all day, so a 30 mile passage will probably
require some night sailing. A number of conventional Potter 15s have sailed
to Catalina Island, about 26 miles.

The lateen rig is definitely simpler, but as to which rig would be safer
for long passages, I can't say. Either rig would work so long as it was
strongly built and had reefing capability. The sloop rig provides
capability to heave to, which I'm not sure you can do with the lateen rig,
although Brown says you can heave to with the reefed lateen sail. You MIGHT
also have a slight edge in pointing ability with the sloop rig, which could
be important if you're trying to claw your way off a lee shore and don't
have a working motor. Adding a socket for a lateen rig mast does not
prevent using the original sloop rig, so I would recommend a lot of
practice with both rigs before undertaking the Bahamas, and then decide. I
don't know of any P15s that have ventured to the Bahamas, but I know of one
that sails the San Juans.

The lateen rigs used, either Sunfish or Aquafinn, are designed for light
board boats, so it remains to be seen how they will hold up on the heavier,
stiffer Potters over the long haul or in sustained strong winds.
Occasionally an upper spar will be broken on a racing Sunfish. The rig is
flexible, and both the mast and spars visibly bend under load. This allows
them to spill some wind in a gust and contributes to the greater stiffness
(less heel) of the Potter with the lateen rig, as does the low aspect ratio
and lower center of effort. The absence of stays to limit the boom travel
when things are getting out of control could prevent a capsize under some
conditions.

I'm posting this to the Potter mail list, so I'm sure you will get some
more answers from the group.

Regards,
Harry Gordon
P14 #234, Manatee
Mountain View, CA