Does VHF need external antenna?

Yes, don't try to transmit without an antenna, you will probably blow the output transistors.

Options are, in descending order of performance,

1) Do it properly, VHF antenna at the top of the mast. Sailboat antennas are 3db gain.

2) Do it half properly, VHF antenna on the stern pulpit rail. Not too bad an option, certainly much better performance than a handheld. Again, you want a sailboat 3db antenna, NOT a powerboat one.

3) Emergency quarter wave antenna inside the cabin. Might as well get a handheld at that point.

A VHF radio with decent antenna is about the best and most cost-efficient piece of safety equipment you can have.

NautiG said:

You need an antenna. The vhf might barely work without it. You might receive some strong signals from the coast guard or a nearby ship, but you won't be able to transmit more than a short distance without an antenna. If you want a cheap vhf, I would go with a handheld unit. Find one used or on clearance, and sell the one you have on ebay.

Scott
Gemini Catamaran Split Decision

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You won't be able to transmit, at all.

hellosailor said:

If you want reliable communications, permanently installing a mast-mounted antenna (with a loading coil in its base) is the way to go. If the investment (good cable & fittings cost money too) overall is not immediately justified, then even using an "emergency" antenna or a home-made one beats nothing at all.

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Those aren't the only options, though. A proper 3db sailboat antenna mounted on the stern rail is the best option if the OP isn't willing to put one on top of the mast.