Re: Matha Jane

> --- mannthree wrote:>
> > Is there a picture somewhere
> > that one can view?
> > John Mann
>
> Bruce,

> a note asking about the Martha
> Jane stability retrofit.
>
> I think that at a minimum they
> recommend adding the flotation
> boxes and the 500 lbs steel plate
> shoe ballast.
>
> Also, I put a scan of the image at:
>
> And, yes the new lee boards look like
> an improvement. Reminiscent of the
> lee board upgrade on Fast Motor
> Sailer, I think.
>
>http://hallman.org/bolger/510/

> I recommend that you drop PB&F
> a note asking about the Martha
> Jane stability retrofit.

> Is there a picture somewhere
> that one can view?
> John Mann

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--- Inbolger@yahoogroups.com, "Nels" <arvent@h...> wrote:
Bruce Devlin's shop built the
> St. Valery that appeared in WB!
>
> Cheers, Nels

Course I meant Sam Devlin, Got my boat builders and golfers mixed up.

http://www.devlinboat.com/stvalerie.htm

> --- mannthree wrote:
> > ...my Martha Jane
>
> Bruce,

> modifications, PB&F recommend that
> you should. You should fax the to
> learn more.
>
> ==cut and paste of text from MAIB below===
>
> PHIL BOLGER & FRIENDS, INC.
> BOAT DESIGNERS, P0 BOX 1209 FAX 978-282-1349
> GLOUCESTER, MA 01930, USA
>
> Bolger on Design Martha Jane #510 Revised
>
> The Martha Jane leeboard sharpie design was prepared
> in 1986 for the late Elrow LaRowe (named for Mrs.
> LaRowe). They were intended for efficient trailer
> hauling and for backwater camp-cruising. I commented
> in Boats With An Open Mind that One or two Martha
> Jane's have made offshore passages and kept the sea in
> gales. I wouldn't set off far to sea in one myself if
> I could help it. If I had to do it I would be very
> careful, but not much frightened.
>
> A large number of these boats have been built all over
> the world (LaRowe and others had rights to sell the
> plans at one time and another, and the numbers could
> be anywhere from several dozen to several hundred.) We
> have sailed two of them, finding them good sailers and
> exceptionally handy. All the owners that we heard from
> liked them, and several of them made notable inland
> and coastal cruises on their trailers and on their
> bottoms.
>
> In 1999 we heard from the second owner of one of them
> (which in previous hands had sailed for some years
> without problems), that the boat had capsized. We
> attributed the incident to flooding through an
> unsecured off-center open hatch, not on the plans,
> near the stern in the sunken afterdeck, but it
> happened again with the hatch closed. In the second
> case the boat recovered when her single-handed skipper
> got his weight out on the lowered weatherside
> leeboard.
>
> Early this year there was a more serious incident of a
> new boat which capsized, flooded, and turned
> bottom-up. This boat had been modified with a stern
> rudder and different ballasting, and the immediate
> cause of the accident was apparently the boat going
> out of control due to trouble with a mizzen sail, most
> of the ties of which had parted from the mast. But as
> far as we could tell her stability characteristics had
> not been significantly altered. The owner of this boat
> described the accident on the internet, and was
> contacted by several other owners whose boats had
> capsized. None of these had informed us, and still
> have not done so, but it looked as though the reserve
> stability of at least some boats of this class was
> less than we had estimated and had too little margin
> for inaccuracies in building, and for mistakes in
> handling, to be tolerated. Predictably, in boats of
> such light weight, MJs with cruising gear and supplies
> seemed to be steadier on their feet.
>
> Martha Jane was designed before it was customary, or
> practical with much accuracy, to calculate the
> stability of small boats. With advances in software
> and hardware capability and user-friendliness over the
> years, it has become decidedly easier to do, and we
> reassessed Martha Jane's characteristics across a
> range of structural weights, loads, and
> hull-geometries. The program has to be given a center
> of gravity, and calculating that accurately is still a
> tedious business.
>
> Stability Curve #1: We ran calculations for Martha
> Jane, on pessimistic assumptions of weight location,
> and found that her point of no return was about 60
> degrees, with a substantial negative range until the
> sealed and buoyant masts and yard immersed. Their
> volume stabilizes her and she should float on her side
> with masts under water. But if some force rolled her
> on down to 138 degrees she would go on to bottom-up.
>
> All this fits the reports: 60 degrees is an angle that
> most owners would not allow to happen; a boat might
> sail many years without being heeled that much, until
> some bad luck or bad handling showed up the danger
> point. Moreover, this characteristic is what most
> people expect of sharpies and of very shallow boats in
> general. Probably the reason we did not hear about the
> capsizes was that most people took it for granted that
> the boats were capsizable. Incidentally, we ran this
> check in both light and heavy weight estimates. The
> one shown is the heavy one, implying a weight of 2200
> lbs on the trailer with the water ballast dumped.
>
> The weakness of the design is in the very low actual
> freeboard forward and abaft the raised deck/cabin
> structure. It is masked by the high bulwarks, but the
> effective freeboard is to the top of the sunken deck,
> 20" aft as designed and less with several people
> sitting there. If the boat is knocked down on her side
> the righting force of the watertight volume in the
> after part of the boat is only about a foot above the
> ballast center and actually below the center of
> gravity of the boat; that is, it tends to capsize her
> rather than to right her at extreme angles of heel.
> Also, in a beam-ends knockdown, the crew naturally
> brace themselves with feet on the lee gunwale, with
> their whole weight actually contributing to the
> capsizing force.
>
> Stability Curve #2: The low afterdeck is one of the
> pleasantest features of the design for comfort,
> shelter, security, and efficient weight placement for
> normal sailing angles of heel. Any retrofit to improve
> the reserve stability of the boats should retain this
> feature of the design. We therefore designed sponsons
> on the outside of the bulwarks at the stern. These
> sponsons add about 200 lbs of buoyancy on each side
> and make a substantial improvement in the boat's
> reserve buoyancy and reserve stability. They will have
> no noticable effect on the performance or behavior of
> the boat in normal sailing attitudes, and very little
> effect on her looks except for their shadow if the
> sides are light-colored.
>
> We recommend that these sponsons be fitted to all
> existing and new boats to the Martha Jane design. What
> they don't do is improve her potentiality for
> capsizing very much, since they don't take effect
> until the boat is past the capsizing angle. Boats with
> this modification will be much easier to right after a
> capsize; somebody getting out on a leeboard, or
> releasing the main halyard, should allow the boat to
> right herself, but alert sailing in puffy weather is
> still very desirable!
>
> Stability Curve #3: Thus we looked at the effect of
> adding some ballast. The boats can stand the weight,
> even the numerous ones that are more or less
> overweight. If the ballast is added in the form of a
> 1/2" thick steel grounding shoe 4' long, amidships,
> and the full 6' width of the bottom we get about
> 5OOlbs. This shoe can be faired in with shims and
> epoxy forward and aft. The added drag is negligible
> and the power to carry sail is increased; that is, she
> would be faster to windward in strong wind.
>
> Incidentally, none of these curves consider the effect
> of live ballast in normal sailing, although it is
> allowed for at the extreme angles when it may have a
> bad effect. Now this curve is in the "offshore" range;
> if she was rolled bottom-up by a breaking sea, the
> next wave would right her. As in all these curves, the
> sharp rise in positive stability beyond 100 degrees is
> caused by the buoyancy of the mast, yard, and boom as
> they're immersed. If she was dismasted in a violent
> rollover, she would be relieved of their weight and be
> much more stable over to 90 degrees.
>
> Stability Curve #4: The good effect of the ballast
> shoe depends in good part on the sponsons. Without
> them the stem would settle when the after deck
> immersed at extreme angles, and she would capsize at
> 82 degrees.
>
> Other Upgrades, Stability Curves #5 and #6: We've
> taken the occasion to draw up some other upgrades
> suggested by fourteen years of experience with these
> and many other designs (a hundred and forty-eight
> designs since M-J). First, the windowed raised house
> amidships. This vastly improves the previously austere
> cuddy with 5'6" headroom (under the companionway
> hatch), and by creating a panoramic view out
> encourages crew to sit inside for shelter, shade, and
> improved sailing trim of the boat.
>
> The buoyancy of this much higher raised deck also
> produces a further large increase in the reserve
> stability and buoyancy of the boat, as shown in Curve
> #5. This one shows that the combination of added
> ballast and the high house produce a boat about as
> foolproof as they come. With the house but without the
> added ballast the effect isn't as dramatic but she's
> still entitled to be called self-righting (Curve #6).
> This option reduces the weight on the trailer by
> slightly less than 500 pounds (the higher house weighs
> a little more than thc original low raised deck by the
> amount of vertical structure in the form of framing
> and polycarbonate).
>
> We recommend that all Martha Jane's be retrofitted
> with the sponsons, and with either the added ballast
> or the high house, or both. house in other ways than
> stability, and it is Adding the ballast will be
> simpler on existing recommended. Since half of her now
> 1,000lbs boats. New boats will benefit from the high
> ballast is water and can be left behind, adding }
> 5OOlbs is too bad but should not ruin most tractor and
> trailer combinations.
>
> The house is shown extending over the forward end of
> the afterdeck, at the sides, to give some shelter
> there requiring a tiller extension. This overhang
> could be supplemented Bill Jochems' M-J in Colorado.
> No capsizes. 28 by a tent over the rest of the
> afterdeck to make it habitable at anchor in bad
> weather. We recommend this alteration in all new boats
> of the class, and that it be considered for existing
> boats especially if and when they are due for a major
> overhaul.
>
> The revised leeboard design, developed and tested in
> other designs over several years, will correct the
> tendency of the original leeboard design to kite off
> the hull. Existing leeboards will benefit by added
> ballast as close to the leading edges of the boards as
> possible. The new leeboard design allows both boards
> to be left down on all points of sailing, and precise
> adjustment of their position, independently of each
> other, for control of helm balance and steering
> steadiness. For instance, with one board down vertical
> or raked forward, and the other raked aft to the
> partly-hoisted position, the boat will tend to hold
> her course with free tiller for useful periods. With
> the pendant and downhaul arrangement of control, the
> boards need no ballast, eliminating the lead inserts
> and making them lighter to raise. This alteration is
> recommended for new boats and as a worthwhile retrofit
> to existing boats. In new construction this option
> will eliminate having to melt lead.
>
> Lastly, we show an optional steering arrangement with
> twin rudders on the stem, in place of the kick-up
> rudder under the hull. The original rudder design has
> been practically the only feature of the boat which
> elicited any complaints before the stability question
> came up. It gave sharp control, placed a simple tiller
> in ideal relationship with the best position for the
> helmsman, no dragging of her tail, and left the stem
> clear for a neat motor mounting position and for the
> mizzen sheet boomkin.
>
> The drawbacks were that it was reasonably complicated
> and costly to build and that it needed a cotter pin
> (or a bungee-cord rig) to keep it from kicking up when
> the boat reached a certain, not very fast, speed.
> Pencils made good cotter pins, being about the right
> strength to break if the exposed rudder struck or if
> the boat came down on it in a grounding.
>
> The twin rudders indicated are the best alternative we
> have thought of at this date. They are very simple to
> build and hang on standard heavier-duty pintles and
> gudgeon. They will give somewhat steadier, but not as
> quick, steering, will work on any draft that the boat
> can float on, and allow the cutout in the bottom panel
> to be eliminated. There might be a side effect at
> alarming angles of heel with the total effective
> rudder area in the water reduced when the windward one
> lifts clear of the water, and the leeward one being
> loaded up with additional pressure behind the pivot,
> the combined effect of which could be a degree of
> rounding up if overpressed. Until that's actually
> observed she is to be considered as having to be
> sailed by the helmsman in and out of potential
> trouble.
>
> Now Martha Jane is safer, a bit easier to build, with
> the savings in stainless and lead work put into
> polycarbonate transparency on the house, and while the
> original version served quite a few inland and ICW
> "roamers" well, she has become more of a cruiser yet.
>
> Complete plans for upgraded #510 Martha Jane on seven
> 17"x 22" sheets are US $250 to build one boat. Upgrade
> on 2 sheets for #510 Martha Jane are US $50 to upgrade
> one extant boat.

> --- mannthree wrote:
> > ...my Martha Jane
>
> If you have not made the Martha Jane
> modifications, PB&F recommend that
> you should. You should fax the to
> learn more.
>

> ...my Martha Jane

> Sorry about the late response to this posting but during my

>
> It is a bit awkward to set and get down but over it works well.

>
> Peter Adams
>
>
>
> [Non-text portions of this message have been removed]

> Some in the group with a Martha Jane, or boat with similar rig, may