Current Technical Articles
Jordon Drogue & Dictionary
We were going through the materials stored away on the machine and came acrosss these bits of information. (1) How to make a Jordon Drogue. This is an old typewritten document that shows it all. The document needs to be preserved and hopefully we have sufficient energy and $$ to make this happen. (2) Cruiser's Dictionary that has a lot of information electronically stored so you can access it by computer. This would be a great addition to a Thumb Drive.
Nominal Load Carrying of Copper Wire:AWG: In the American Wire Gauge (AWG), diameters can be calculated by applying the formula D(AWG)=.005·92((36-AWG)/39) inch. For the 00, 000, 0000 etc. gauges you use -1, -2, -3, which makes more sense mathematically than "double nought." This means that in American wire gage every 6 gauge decrease gives a doubling of the wire diameter, and every 3 gauge decrease doubles the wire cross sectional area. Similar to dB in signal and power levels. An approximate form of this formula contributed by Mario Rodriguez is D = .460 * (57/64)(awg +3) or D = .460 * (0.890625)(awg +3).Metric Wire Gauges (see table below) Metric Gauge: In the Metric Gauge scale, the gauge is 10 times the diameter in millimeters, so a 50 gauge metric wire would be 5 mm in diameter. Note that in AWG the diameter goes up as the gauge goes down, but for metric gauges it is the opposite. Probably because of this confusion, most of the time metric sized wire is specified in millimeters rather than metric gauges. The following link will take you to the table.
Galvanic Reaction Metals Table:The table is the galvanic series of metals in sea water from Army Missile Command Report RS-TR-67-11, "Practical Galvanic Series. The Galvanic Table lists metals in the order of their relative activity in sea water environment. The list begins with the more active (anodic) metal and proceeds down the to the least active (cathodic) metal of the galvanic series. A "galvanic series" applies to a particular electrolyte solution; hence for each specific solution which is expected to be encountered for actual use, a different order or series will ensue. The sea water galvanic series is the most complete series that I know and I have not seen another series published by either the Army, Navy, or Air Force. Civilian aircraft encounter moisture and a salt of some kind. The following link will take you to the table.
Battery Thermal Runaway defined: The operating temperature which is reached in a battery is the result of the ambient temperature augmented by the heat generated by the battery. If a battery is subject to excessive currents the possibility of thermal runaway arises resulting in catastrophic destruction of the battery. This occurs when the rate of heat generation within the battery exceeds its heat dissipation capacity. There are several conditions which can bring this about: * Initially the thermal I2R losses of the charging current flowing through the cell heat up the electrolyte, but the resistance of the electrolyte decreases with temperature, so this will in turn result in a higher current driving the temperature still higher, reinforcing the reaction till a runaway condition is reached. * During charging the charging current induces an exothermic chemical reaction of the chemicals in the cell which reinforces the heat generated by the charging current. * Or during discharging the heat produced by the exothermic chemical action generating the current reinforces the resistive heating due to the current flow within the cell. * The ambient temperature is excessive. * Inadequate cooling Unless some protective measures are in place the consequences of the thermal runaway could be meltdown of the cell or a build up of pressure resulting an explosion or fire depending on the cell chemistry and construction.
Hull Identification Number:All vessels built or sold in the USA after 1972 must have a complete Hull Identification Number before the registration application can be processed. Please inspect your vessel for the Hull Identification Number. The HIN consists of 12 continuous characters at least one-quarter of an inch in height, uninterrupted by spaces, slashes, hyphens or other symbols. The HIN will be carved, burned, stamped, embossed, molded, bonded, or otherwise permanently affixed to the vessel. This link will take you to more details.
Understanding IP Ratings:This link will take you to a pdf file that you can look at and print if you desire. No more mysteries!
Bobstay Bracket Safety Information by Jim Bach of Zephyra
The assembly process used in the construction on the YS 35's have baffled all of us at one time or another but I think that
replacing the bolts on the bobstay bracket was one the most interesting two days I have spent this past year.
We were sailing along the coast of Spain with a brisk southerly blowing, doing a healthy 7.5 kts, rail down and for once I
was at the helm smiling. The loudest bang rang out, more like a pistol shot than hitting something in the water but of
course that was the first place we looked. On closer inspection, we discovered that the lifelines forward were slack and
that the mast was on the wobbly side. Instantly off the wind to reduce sail and then go forward to have a look at the
problem.
The bottom bolt holding the bobstay bracket, the one attached to the hull had given way and the bracket had bent under
pressure to a 90 degree angle allowing the stay itself to slack. The release of the pressure and I must assume it is
something tremendous from the sound caused the bowsprit to move up some 3 inches over normal. The only thing holding the
mast at the bow was the staysail stay and it was now under extreme pressure. We limped into Alicante Harbour and over the
next three days tried to replace the bolt. A most interesting and baffling process.
A local metal shop straightened the bracket using heat to ensure that the the metal did not fatigue. We had that back the
next day but in the meantime we had to remove what was left of the bottom bolt. The cap had broken off due to electrolysis
leaving an air gap of one inch inside the hull and an estimated 6 inches of bolt further inside after that.
We removed the 300 feet of anchor chain and the 250 feet of rode to lighten the bow. This moved the bolt an inch over the
waterline.
Try as we may we could not seem to cause the bolt to move. We tried knocking it with a sludgehammer (goodly sized one) from
both ends to no avail. We then used a dremel on the inside of the V (alas removing almost everything in the forepeak for
access). The removal of an inch of fiberglass that had been poured on the inside over the nut showed the stem and a bolt;
but using pressure and force from the sludge provided no movement what so ever on the bolt.
We then dug deeper into the fiberglass and it revealed a coller that was between the inside stem and nut and the outside bolt
(the one that had broken).... Once the glass was loose we only had to bump it with a screw driver to have it come out
altogether.
The shalft coller was the length of three half inch bolts, so we crazyglued three nuts together and slowly and carefully
threaded the replacement half inch bolt from the outside of the hull to the inside. This ensured that the space originally
taken by the collor was filled with something solid and it wouldn't leak when we put back to sea. A little chauking/sealant
povided the remainder of the seal..plus a lot of pressure on the two bolts and a washer we put on.
For insurance we poured back the inch of covering fiberglass. I am sure some of this made its way along the replacement bolt
to ensure that it would stay intack later. All in all about two days of groaning and moaning and wondering how the devil
they got this together in the first place. Actual work .. about 30 minutes.
So if have a moment on a calm and somewhat warm day, I suggest that you take out the bolt holding the bottom of the bobstay
bracket, after first releasing the pressure using the turnbuckel and ensuring that you have no corrosion on this very high
pressure point. A ounce of prevention here will certainly replace a 5 pound sludge and an almost demasting sometime in the
future.
If I have not made myself clear about the replacement process, ask away and I will try and clarify it if I can.
Take care all, Jim
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Hi Jim
I ran into a very similar problem, except I did not have sufficient access to the anchor locker as the Samson Post was in the
way. The bobstay bracket was too low as the lower half was always in the water, I moved it up so the bottom hole is now at the
level of the top bolt. That solved the problem. As the fitting used to be in the water it had crevice corosion on the back side, will have to make a new fitting.
I spend 4 years in the Med, loved it and Turkey was the very best of it all.
Mike
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Hi,
The bobstay on my YS was located at the same position, I removed it and the back side was corroded badly, I moved it higher by putting the bottom bolt
at the he top location and drilling a new hole for the top bolt, it is now clear of the water except when I am sailing when it gets its regular
dunking.
Still have to have a new bracket made.
Mike L