16' Cruiser with Radar?

[oldgrowth]

[thataway]

A comment about AIS (Automated Identification System) mandated by SOLAS on many commercial vessels. See:
http://site.ialathree.org/pages/AIS/aisfaqs.pdf for an excellent explaination. It is not a "coverage" as it might be with DSC or a VST scheme. It is dependant on the various vessels using the AIS transponders. For the most part in small recreation vessels we are limited to recievers at this time. (FCC has not approved a number of units which will also transmit and be suitable for small boats).

The resolution of radar does not depend on its power. You are correct that the penetration of rain, may be better with 4 KW--but again with over 100,000 miles using radar, the 2KW has always been adequate.
What is important is the descrimination of targets--and that is dependant on scanner antenna size--the wider the antenna, the narrower the beam and the better is the descrimination--the ability to recognize two targets which are close together.

A height difference of 8 feet off the water or 12 feet off the water for a radar antenna, makes no practical difference. For the most part small recreational boats will be on a 3 to 4 mile range of the radar. (Perhaps going to 16 miles peroidically)--and the targets will mostly be at least 4 feet off the water--(some exceptions, such as lobster pots with radar reflectors on the floats).

The only time I have lost GPS signal in open water, has been in the proximity of military vessels. The "shadow" of a radar antenna in the center of the cabin top, is very small, when the GPS antenna is mounted off to one side, or fore or aft of the antenna (again out of the direct beam). Actually I have run GPS successfully with internal antennas in the C Dory 22, 25 and TC 255.

It is that occasional gas station, or other low obstruction which we don't think about which can catch a boat with an antenna which is high. We have a 2 meter Ham antenna on our truck which is several inches higher than the highest item on the C Dory/Tom Cat cabin top.

Absolutely, a compass and paper chart are required items on any boat. But so should be a DR position every XX minutes. This is what we used to do before GPS--I wonder how many folks do this now? All is well and good in excellent visability--it all of a sudden becomes much different in pea soup fog. Having the radar, to show the shore line/boats, and landmarks, as well as the depth sounder to show bottom contours helps in any navigational situation. Of course, we carry a hand held GPS and VHF radio in a sealed metal box, along with a lead line...just in case...

[blueseas]

[blueseas]