Sea cocks are very handy to have when you have to change out a hose. Assuming that the seacock can be easily closed/opened that is.
The above is not taking into account any other safety
issue, which is up to you.
I use non-wire reinforced marine exhaust
hose on all my thru hull
drains (cockpit, sink, raw water
filter) with double clamps.
Wire reinforced hose will eventually fail when the wire wears thru the rubber covering. I have seen this happen many times, usually as the result of no inspection
or replacement of the hoses. Use a mirror to inspect all sides of a hose where ever there is even the slightest bend as this is where the wire will come thru.
For short term repairs
to get you to a safe harbor, instead of cutting and plugging the hose you can just tape the hole/tear in the hose. Use a super aggressive type of "duct tape" and while it may not completely stop all water ingress, you can slow it down to a less than 10% leak and still have the use of the drain hose.
You can pump out what water the tape can not hold back.
Personally, I would rather spent just a couple of minutes taping the hose than slashing around with a sharp knife under the cockpit in rough weather
trying to cut thru a rock hard rubber hose and then be swing a hammer to pound in a wooded plug!
While you can dive over the side and pound in a wooden plug
, doing so in anything other than a FLAT calm day in warm water is asking for more trouble than you want!