[Rhodes22-list] Other boats and IMF's and sail plans for Art C.
Tootle
ekroposki at charter.net
Fri Nov 14 08:42:18 EST 2008
Art,
In regards to putting another style mast and sail on other boats requires
more than changing stays, mast base and some hardware. Naval Architects
analysis hull shape, center of buoyancy, center of effort, stability and
other technical factors to determine sail plan efficiency and safety.
I have said many times on this form, I was in Vermont when the guy capsized
his brothers Mac 26 and killed two kids. He did not adequately fill the
water ballast and the kids were not wearing life preservers.
Adding a IMF to a Mac 26 without adequate analysis of the mentioned above
would just as dangerous. Yes, you should hold your breath and not have
anyone else on the boat.
While I was rebuilding the O’Day 26 I asked Commodore Spitzer several
technical questions. Together we went over the potential of putting his IMF
on the boat. Stan has put his mast on other boats, generally equal or
smaller in size.
You said, “Given that most of the driving power comes from the genny, and
your's would be a 155-175% versus a 130, I suspect a net gain.” I would
suggest that you are wrong. You assume that all sail power comes from the
genny. I sincerely question that assumption. Yes, on this forum that has
been stated that is so on the Rhodes 22. I would question whether all sail
plans that include a foresail get significant power from that sail. And you
have not begun to analysis slot effect.
The sail plan for this boat is small foresail and large main sail. I am not
a Navel Architect not do I have Stan’s over 60 years of experience of sails
on different boats. Off hand I would say that on the existing sail plan the
work of the sails on this boat is coming from the large main. The foresail
provides pointing ability and slot effect.
Also, C. Raymond Hunt designed many sail plans for his racing son, Jim Hunt.
While Ray was probably not involved, Jim was president of O’Day at the time.
Since both are sailing the wild blue yonder we cannot ask the questions.
John Deknatel will not speak to the subjects, for whatever are his reasons.
There is very little documentation. Probably most of the knowledge was in
their heads.
The boom on this boat is even longer than the boom on its cousin the O’Day
25. If you look at pictures of the ‘Skipjack’ and cat boats then you get
the idea of the sail plan used on it. An IMF sail plan might require a
different location for the mast. Mast are not stuck anywhere on a sailboat.
Their location is intrinsic in the boat’s design and projected sail plan.
I have to ask, what would be the effect on stability of going to a large 175
Genoa as its foresail? You have already disregarded the concept of
stability in suggesting putting an IMF on a water ballasted boat. Do any of
the boats using water ballast use an IMF? If not, ask why not.
There are many good books on sailboat design and all usually discuss sail
plans. There are also several good books on sails, for example, The Art and
Science of Sails by Tom Whidden of North Sails.
I am not precluding an IMF on this boat, although because of its age I
question any large expenditure. However, I suggest that some good analysis
would be a good approach. I would suggest that weight aloft needs to be
competently evaluated on stability of new sail plan.
Ed K
see: See: http://www.bertram31.com/ray_hunt.htm
hparsons wrote:
>
> Don't know if you mean the Mac26 that is also a powerboat. If so, I
> don't think that's an experiment I'd try. That boat is very tender when
> that ballast is empty for "power boating" mode. I would avoid any
> modifications.
>
> Arthur H. Czerwonky wrote:
>> Herb,
>> Looking at a snapshot of the O'Day 26, the spreaders are straight out, so
>> the upper and lower side stays should be compatable (modified only for
>> length). The shoe for the mast bottom is available from Rudy Nickerson
>> (D&R Marine in Mass). Ed would have a neat craft with that IMF attached,
>> especially nice with the large genny and the additional ballast. Nice 26
>> advertised in Racine Wisconsin. I have been tempted to put an IMF on a
>> Mac26 with full water ballast and hold my breath.
>> Art
>>
>> -----Original Message-----
>>
>>> From: Herb Parsons <hparsons at parsonsys.com>
>>> Sent: Nov 12, 2008 9:58 PM
>>> To: The Rhodes 22 Email List <rhodes22-list at rhodes22.org>
>>> Subject: Re: [Rhodes22-list] O'Day 26 w. IMF
>>>
>>> Actually, that last little bit is intriguing. The O'Day's mast is deck
>>> stepped, using a a plate, really looks more like a shoe. It would be
>>> pretty easy to buy another one of those, attach the other mast, and
>>> switch it out.
>>>
>>> The shrouds would be another story, but it's not like you'd have to
>>> redesign half the boat to do it as an experiment.
>>>
>>> On thing I would be cautious about, the O'Day only has 6 stays total,
>>> forestay, back stay, and two shrouds on each side.
>>>
>>> Arthur H. Czerwonky wrote:
>>>
>>>> Ed,
>>>>
>>>> Given that most of the driving power comes from the genny, and your's
>>>> would be a 155-175% versus a 130, I suspect a net gain. Battened main
>>>> matters not since you would be using the IMF sail/mast combo with IMF
>>>> boom. You would need to add a mid-boom bail and block to the traveler,
>>>> of course. I'm not sure about alignment of the spreaders and
>>>> chainplates.
>>>>
>>>> I was once contemplating installing my spare IMF mast to a non-R22
>>>> boat, but have never gotten a round tuit. The mast should fit, and the
>>>> boat should do about the same as Stan's 26' creation. Just an idea to
>>>> chew on.
>>>>
>>>> Art
>>>>
>>>> -----Original Message-----
>>>>
>>>>
>>>>> From: Tootle <ekroposki at charter.net>
>>>>> Sent: Nov 12, 2008 8:27 PM
>>>>> To: rhodes22-list at rhodes22.org
>>>>> Subject: [Rhodes22-list] sailing reply to Arthur
>>>>>
>>>>>
>>>>> Art,
>>>>>
>>>>> Rhodes sail ='s 210
>>>>>
>>>>> O'Day sail ='s 278
>>>>>
>>>>> On a small boat that is a big difference.
>>>>>
>>>>> Also O'Day is a battened main (4).
>>>>>
>>>>> Genoa usually 130% standard.
>>>>>
>>>>> Mast height on R = 26
>>>>> Mast height on O = 28
>>>>>
>>>>> Ed K
>>>>>
>>>>>
>>>>>
>>>>> Ed,
>>>>> I expect the R22 IMF would be nice on your 26' O'Day, although the
>>>>> stays
>>>>> would need to be changed. If the mast were used, the corresponding
>>>>> boom
>>>>> would need to be used and the genny also. I doubt much significant
>>>>> loss in
>>>>> speed, alot gained in convenience.
>>>>> Art
>>>>>
>>>>>
>>>>> --
>>>>> View this message in context:
>>>>> http://www.nabble.com/sailing-reply-to-Andrew...-tp20468855p20472957.html
>>>>> Sent from the Rhodes 22 mailing list archive at Nabble.com.
>>>>>
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>>>>>
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>>>>
>>>>
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