Thinking about this, I wonder what would happen if the Morad hit an air obstruction. I have considered replacing my Shakespeares with Morad next time I need a replacement. But I also want the current height of 8 foot above my boats roof. The SS is not going to flex like a fiberglass. So would it break the mount or possibly crack the fiberglass bulkhead? Mounts are cheaper than either type antenna. Patching a fiberglass bulkhead might not be.
Colby
SS whip is extremely flexible--far more than flexible than a fiberglass antenna. You could bend the whip permanently..it is approximartly 1/8" diameter. The whip is about 36" long, The Aluminum tube is about 16" long. Total length is 4.5 feet. If you plan on hitting objects with your marine VHF antenna, I advise get a spring base, as used on many Ham antennas for vehicles. It may take a little searching to find one in SS. Or use a plastic base. It will crack far sooner than a SS base will.
To get to the 8' at the top you will need a 3.5' long SS pipe for the extension. If you hit that, then the obstruction will most likely take out other items on the cabin top such as your radar. (Incidentally most radio guys do not approve of flying flags from your antenna. It puts undo stress on it.)
Morad also makes a 10 dB gain antenna. This is a brute, and it could cause damage as you suggest, but it is rarely used on vessels less than 50 feet. Any long antenna needs a second support. I don't have any handy photos, but the HF SSB fiberglass antenna for marine radios is 23' long. On my Cal 46 it was mounted on the deck and then supported with a stand off by my 9' tall radar arch on the back of the boat. That arch also had my Radar, 2 meter meter antenna, a back up (for the mast head) primary VHF radio antenna, air horns and another type of ham antennas: Firesticks; Hamsticks, which can be had with a SS spring base.
I am not sure what "Bulkhead" would be involved with mounting the VHF radio antenna--If the Cabin top is only 1/4" thick fiber glass, it should be backed up with a larger than the footprint of the antenna mount (Even Starboard, but aluminum plate would be better.). The 25's roofs are not all built the same. Some have no core in part--and where the core is can vary. (The raised portion vs the lower outer side/forward part.). Ideally the core would be in both sections--and even then any antenna should have fender washers under the four 1/4" bolts for the antenna base.
