There is a way to check the accuracy of a tachometer using the highly accurate and stable frequency of AC power supplied from any source of commercial shore power. The concept is to use the AC line frequency as the measuring standard. The only tools needed for this calibration check are a piece of tape and a fluorescent lamp which operates from commercial AC line power.

A fluorescent lamp is actually a gas-discharge lamp with the interior of the glass envelope coated with a light-emitting phosphor. When the gas within the lamp is ionized by alternating current it emits pulses of energy. One pulse occurs for each of the voltage excursions of the AC waveform. For the 60-Hz power common in North America, there will be 120 such flashes per second, 60 positive and 60 negative. The pulses of energy created within the lamp excite the phosphor coating, which in turn emits visible light. Because the energy driving the lamp is not continuous, the light emitted is not continuous. The fluorescent lamp emits 120 pulses of light per second, but the human eye’s persistence of vision makes us think the light is always on. We can use the pulsing light output of the fluorescent light as a very accurate measuring tool with which to check the calibration of the engine tachometer.

First, obtain access to the front of the engine. Place one piece of white tape on the face of the large pulley mounted on the engine’s crankshaft (usually this is the largest pulley in sight). Illuminate the front of the engine with light from the fluorescent lamp. Run the engine at 1,800 rpm, as shown on the tachometer. If the tachometer is accurate, four stationery, or very slowly moving, white marks will appear on the face of the pulley where the tape was placed. If the tachometer is inaccurate, the tape marks may be rotating in either direction. Adjust the throttle until the four tape marks appear to stand still. Note the tachometer reading. If the difference between the reading and 1,800 rpm is at all significant, look for a small adjustment screw on the back or within the body of the tachometer. Turning this screw slightly should make the indicator needle move to exactly 1,800 rpm. If the speed range of the engine permits, increase the engine speed to 3,600 rpm. At this speed, only two tape marks should be visible on the crankshaft pulley. Repeat the check of the tachometer reading and, if necessary, readjust the tach. The basis of this stroboscopic speed calibration is quite simple. At 1,800 rpm, the engine is turning at 30 revolutions per second. The lamp is flashing at 120 flashes per second, or four flashes per engine revolution. Therefore, if the engine is turning at exactly 30 revolutions per second the tape mark will appear four times, with each apparent tape position 1/120 of a second or 1/4 revolution apart. When the engine runs at 3,600 rpm there will be only two light flashes per engine revolution. If the boat is in a country where the standard AC power frequency is 50 Hz, the check speeds would have to be 1,500 and 3,000 rpm since the light would flash 100 times per second.

LOA vs LWL, looking for a boat – Page 5 – SailNet Community

Quote:Originally Posted by davidpm View PostI just went to sailboatdata and looked up Far 395 etc and it said 25 for SA/D. The crusing boats Catalina etc were all about 17 SA/DWhat am I missing?There are a number of things that come into play. Its mostly about designing a boat as a system. So when you look at modern performance cruisers, they tend to have very tall fractional rigs with minimally overlapping headsails, bendable spars, and an inability to carry large percentage overlap genoas. These are wildly efficient sail plans in terms of drive to drag, and a configuration that can quickly be depowered rather than reefed in a building breeze. But rigs like these generate a lot of heeling moment compared to lower aspect ratio rigs and so need some mix of low drag hull forms and lots of stability. This mix makes sense because lower drag hull forms allow the rig to be smaller and produce less heeling since less drive is needed, and of course the high stability is needed to stand up to the rig over a wider range of wind speeds. In other words, what makes the high performance cruisers of the past decade or so, with their very high SA/D’s work, is that they generally have a huge amount of stability relative to their drag and can therefore get by with these more efficient sail plans. Most of these designs (Think of boats like the J-122, J-130, Aerodyne 38, Cape Fear 38, Farr 395, X-4 etc.) have SA/D’s in the 22 to 26 range measured with their 100% foretriangle. The actual sail area of these boats with their minimally overlapping headsails ends up roughly in the 26 to 28 range. (Even my old Farr 11.6 ends starts in the 22.5 range) In contrast, boats like the Catalinas that you mention, and most conservative coastal cruisers for that matter, are designed around carrying comparatively large overlap genoas in order to get decent mid-range sailing abilities. They are not really designed for light air performance. They generally lack the kind of high stability to low drag, that is required to carry a more efficient rig. Its just a different mindset. The reality is that most of these boats were designed with a generic owner in mind, one who is less concerned about light air performance than comfort and forgiving sailing characteristics. They are set up in ways that is consistent with not sailing at the extremes of the wind range, and without the kinds of sail shaping tools that allow a sail to be depowered quickly rather than reduced in size by reefing or furling. Jeff

Source: LOA vs LWL, looking for a boat – Page 5 – SailNet Community

boating seminar

Maybe you could do something like this?

 

 

 

Sent from my Verizon, Samsung Galaxy smartphone

 

 

——– Original message ——–

From: SEASENSE@aol.com

Date: 7/20/17 2:44 PM (GMT-05:00)

To: liza@base-one.com

Subject: SEA SENSE BOATING

 

 

HI Everyone

 

This email is to let you about an event that will take place at the Shady Harbor Marina on the Hudson River in New Baltimore, NY.

SEA SENSE Captains Patti Moore & Carol Cuddyer will be presenting a women-only boating course on Saturday July 28th.

 

The class will begin in the marina restaurant at 8:30 AM

The morning will cover:

Safety equipment                  Man Overboard

Line Handling                         Anchoring

Knots & Cleating                    Rules of the Road

VHF Radio                             Getting underway/check lists

Discussion on maneuvering twin & single engine boats and time for questions

The afternoon with be spent  practicing on-board boats.

This is day will  provide a great boost to your confidence and safety!

 

Captains  Carol Cuddyer & Patti Moore

SEA SENSE

Seasenseboating.com

Facebook.com/ sea sense boating

 

 

For registration, please contact:

Shady Harbor Marina @ (518) 756-8001

or call Kathy Donovan @ (518) 365-9304

Chainplates – SailNet Community

SailNet Community

Source: Chainplates – SailNet Community

Re: Chainplates

The stainless steel typically used for chainplates has a ‘severe’ lower limit of fatigue endurance. Most 300 series stainless will have a fatigue endurance limit of 30% ultimate tensile strength … UTS at about 90,000 psi. OR a Fatigue Strength at only 30,000 psi.
What this means is that if the chainplate is strained beyond/above 30% of UTS (loading to or greater than 30,000 psi), it will begin to rapidly fatigue; if kept below 30% UTS it will be virtually indestructible vs. ‘fatigue’. If possible, always ‘oversize’ (thickness) when possible.

For the “blue water” typical design which (should) includes an inbuilt 3:1 Safety Factor … historical ‘scantlings’ will show that NEW chainplates should have a high probability of successful service for ONE circumnavigation – about 25000+ sea miles.
For the typical ‘coastal’ design with a 2:1 inbuilt factor of safety – about 2/3 of ONE circumnavigation or 17000± sea miles, then a high probability of failure thereafter.
Fatigue Endurance limit for 300 series stainless is: 1,000,000 ‘load cycles’ that exceeds 30% of Ultimate Tensile Strength …. on a blue water boat this load cycle max. occurs at ~40-45° angle of heel. On a ‘coastal’ design … about a ~30° heel angle.
Even with new chainplates, once you accumulate 1 million load cycles at or above 30% UTS, there is a high probability of sudden catastrophic fatigue failure.

Crevice corrosion – an ADDITIONAL failure mode that WILL shorten the service life and reduce the load bearing value. Even when the stainless is being formed in the mill, micro-cracks will be formed. These cracks, plus cracks due to additive fatigue cracks will begin to form internal corrosion of the metal – thus an additional weakening and besides any simple accumulation of developing fatigue.

Suggestion for long distance sailing:
• For any boat with an unknown in-service life … replace the damn chainplates.
• For any boat with chainplates over ~12 years old … replace the damn chainplates.
• For any boat with chainplates – that have a ‘designed’ KINK or ‘bend’ in them … replace at ~8-10 years.
• For any chainplates that have ‘multiple’ holes for bolting to knees, hull, etc. … pull them off and inspect them for small/teeny cracks inside the bore holes that emanate perpendicularly from the axis of strain (looks like a ‘smiley face’ … | -O- | ) replace immediately.
• Immediately replace any studs or bolts that have developed ‘rusting’, especially ‘blackish’/dark rusting. Ditto, any chainplate that has developed ‘zones’ of black rusting. Ditto, for any polished chainplate that has developed a zone of noticeable ‘dullness’.
• Inspect ‘old’ chainplate studs/bolts with a torque wrench … torque to about 60-70% of the maximum torque value for the bolt or stud. If any ‘break off’ at or below ~60-70% torque value … replace ALL of them for that ‘station’.

Life extension of new chainplates.
• Suggest that you use 316 SS …. if you can afford it, get your 316 with “MILL SPECIFICATIONS” for ‘chemicals and physicals’ (so that you’re ‘sure’ that you’re not buying ‘crap‘).
• POLISH the entire chainplate to a mirror-like surface. If you have the extra-$ available, then have the already mirror-polished chainplates – ‘electro-polished’.

hope this helps.

Used boat values…. – SailNet Community

If one is looking for a good ocean going cruising boat I’ve found the best values to be in what I call “the ports of broken dreams”. These are usually destinations after an ocean crossing where the boat owners have found that sailing just isn’t what they dreamed it would be.Some of these ports are, Honolulu, St Martin, Trinidad and Grenada.Quite often, if you can catch a boat before it has been sitting too long, you can get a fantastic deal on a boat that has virtually nothing wrong with it, it’s just that the owners desperately need cash to restart their lives ashore.Getting a good deal on a boat in the US is more a factor of good research and information than location, but generally speaking boats up north are cheapest in the late fall, just before they are to be laid up for the winter.Also consider the cost of moving a boat from a distant location to where you want to use it, to help you decide if it really is a good deal, or not.

Source: Used boat values…. – SailNet Community

Sailing Conditions and Culture in The Neuse River – Page 2 – SailNet Community

SailNet Community

Source: Sailing Conditions and Culture in The Neuse River – Page 2 – SailNet Community

Letting Go a Moorig Single Handed.

A simple system for letting go a forward boat mooring or anchor from the cockpit.

Source: Letting Go a Moorig Single Handed.

Vinyl wrap sailboat

Knife

Oil analysis