The Sea Mate II was one of a few watches that continued to be produced after 1969 - the year Hamilton was sold to what is now the Swatch Group. It was produced until 1971. Three dials where available... a white butler finished dial, a black dial and also a masonic dial.
The case is 10k rolled gold plate, RGP, with a stainless steel back. It opens through the crystal so it has a two-piece stem. I have found that these one-piece cases with a gold bezel and stainless back must be confusing to a lot of people - as it's not unusual to see pry-marks on the back where someone has tried to separate the two sections.
Inside is a Swiss-made Hamilton 688 movement... the same as an ETA 2390 with 17 jewels.
I recently picked up a Sea Mate II project watch. After an overhaul, dial cleaning, new crystal and a strap - I think it turned out fantastic.


How much would you say this watch is worth?
ReplyDeleteAll fixed up and in serviced condition probably $200, in my opinion. A black dialed version, probably more.
ReplyDeleteI was trying to identify an old watch that I have and Hamilton told me what it was and sent me to your site. Great information.
ReplyDeleteHi,
ReplyDeleteJust got myself a decent example of this SeaMate II.
Missing the male portion of the winding stem and crown. Do you have a source where I might be able to procure a stem and crown.
There seem to be stems for the eta 2390 - but can’t find the split versions that Hamilton used on this model?
Any help would be great.
Thanks.
Russ
Hi Russ. The male portion is a tap 10 male hub. Any tap 10 hub should work fine, as long as it's trimmed to the correct length. If you look on ebay for a "tap 10 male stem" you'll see them
DeleteThat’s great information.
ReplyDeleteThank you SO much. 👍🏼
So, all fixed up and running - got to say, I’m REALLY pleased with the results - just got to find myself a decent crown now!
ReplyDeleteThanks for your help and encouragement. Very much appreciated.
Hello, found your site via internet search in effort to I.D. my Hamiltons.
ReplyDeleteI seem to have a sea mate II but need a new crystal.
The previous owner had a low dome crystal[which I liked], but whoever installed it had put a horribly thick and tall tension ring on it which [1] intruded onto the dial, almost touching the 3,6,9 numerals, and it also stuck up higher than the bezel itself[viewed from the side of the case].
I tried a local watchmaker who put on a new crystal [with tension ring], but his replacement was a 'high dome' which is almost FLAT on top, and the walls protrude pretty high up [ doubling the case's depth] which doesn't look appropriate for a watch w/ a slim case
So... my question to you is this:
What would be the proper replacement crystal for this model?
Does it actually need the tension ring?
where can I obtain the proper replacement crystal?
Low profile crystals are hard to fit to models with sweep second hands. I don't recall the crystal that goes on a Sea Mate II but it doesn't look like it has a reflector ring. Normally a GS PHD style is what is called for, in the correct diameter.
DeleteHello, I’m by no means an expert and can only speak as I find. My example of the Sea Mate II has a nice rounded dome shape crystal, that has no tension ring at all. A crystal lifter is needed to remove it, and it completely self-supports once re-fitted.
ReplyDeleteWith regards to replacement, sorry - I haven’t had to do this with mine, but there are a number of places still stocking crystals for these old pieces.
Hope you find something that fits and does it justice.
Russ
Hello, I bought this watch for 300£ it is worth? Anyway is George wristwatch!
ReplyDeleteGorgeus*
ReplyDeleteI just want to say your website is an incredible resource for a recent vintage Hamilton enthusiast. Picked up my first 60s Sea Mate after researching here.
ReplyDeleteAre new mainsprings available for this watch?
ReplyDeleteMy present watchmaker can't seem to supply one! HELP!!
Find a new watchmaker and look on eBay for an ETA 2390 mainspring
Deletethe ETA 2390 mainspring would be an exact 'drop in' replacement?
DeleteYou can still get those NOS?