MTBF estimates are a statistical concept based on the performance of a sample of devices. They cannot be used to predict the lifetime of a specific unit. In contrast, most mechanical devices fail gracefully. Performance degrades from an optimum level until it is no longer acceptable.

In spite of very careful cost estimating, I still erred on the low side. Veiner's Law #2 is, "It is going to take twice as long for the job and cost twice as much." That came from nearly 50 years of sailboat experience, and it has to be modified for a trawler to maybe, "Twice as long and three times as much."

Without the nozzle it was estimated at about a 10% loss if I remember correctly. I have coupled the Z-drive with a full rudder. At speed the rudder is used to steer. At idle the Z-drive is used to maneuver, along with the bow thruster.

I estimate the curved shapes I used reduced the weight of the framing by half, while at the same time increasing the strength by a considerable amount. Cheers Arild --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.516 / Virus Database: 313 - Release Date: 9/1/2003

I don;t keep very good records but I would estimate: Remove old flooring, 1/4 rounds 4 hours (includes a coat of epoxy on the floor to seal it.

A conservative way to estimate frontal area is to multiply the beam by the height of the superstructure. An even simpler way is to multiply the beam by 3/4 of the beam. By this calculation, my Willard has about 100 sq. ft. of area. A Nordhavn 40 has 160 sq. ft. of area. A Nordhavn 47 has about 195 sq. ft. of area. A Nordhavn 72 has 330 sq.ft. of area.

No one knows how many young kids die each year because of Sudden Cardiac Arrest (SCA), some estimates run into the thousands. This is a bit off topic, so I'll return to the scope of discussion, suffice to say if you have kids, nephews or nieces in Jr. or Sr.

Arena Rock, it is my estimate that since the charts are in vector format, someone who does not know the area, picked the wrong rock. But of course they completely missed the real rock about 3/4 mile further north and very near the traffic line from Pt. Arena to Ft. Bragg. This particular rock is very dangerous as it is just awash at high tide.

I would estimate that in raw distance this is about 50 yards north and about 100 yards east. Is it your claim that the Outdoor Nav chart inset has been corrected to WGS84 before being calibrated? If so, then we need to know that is the case.

The valve could be replaced, but the estimate of parts labor etc runs around $700.