Credit to halekai36..
You have inspired me with your seacock howto to replace some highly questionable seacocks on my boat. But, here is the catch. I'm in Alaska, with access only to a tide grid. Its not real cold, 40's in the day and mid 30's at night, lots of rain, and thats probably going to be my weather until June!!!
I am planning a Glacier Bay in May (before the tourist and permit season) so it is really in my best interest to accomplish my safety list by then before I go powering through ice fields .

Here is my plan: glass in my head suction seacock, replace two cockpit drains, sink drain and install new engine suction (upgrade to 3/4" from 1/2"). So thats 5 seacocks and a 3/4" hole to fill.

My thinking is, since hopefully no glass work will be involved, I can probably do about two thruhulls per tidal cycle. I am not sure if marine filler will cure properly in colder possibly wet weather before the tide comes in. If not, is there any reason I couldn't install flange bolts at a later time when I can do a proper bottom job?
Also, what kind of sealant should I use for the mushrooms knowing they will be submerged in a few hours?

As for the head suction.. Glassing in a 3/4" hole is probably going to be the most difficult, but necessary part of this operation. It is the most worrisome thruhull I have, and needs to go away! Any suggestions of using a West System cold weather formula or other?

Removal of glassed in pipe nipple: die grinder, hammer and chisel?

Suggestions greatly appreciated!

Here are some of my problem children (Perfect example of what NOT to do):
(yes I bought the boat with these, these were part of the price negotiation, yes, I'm amazed at myself I haven't replaced them yet, so no scolding me )

Sink drain GATE valve!

Head Suction

Engine Suction

Cockpit drain

halekai36, err, MaineSail raised a lot of concerns for all of us regarding our through hull fittings. The best I can offer you is that if you provide an outside heat source (in th cabin and perhaps below, in the form of some kind of shelter) you can get the epoxy aka. fiberglass to harden before the tide comes back in.
I also thought that it is recommended to bond or ground your through hulls to the engine block to reduce galvanic corrosion. All of your photos show a healthy blueish dust growing on the bronze or am I missing something?
I would probably pay a yard to haul me out for a few days but I don't live in Alaska and therefore...

That's a very ambitious task for tide cycles! That being said I don't know of any marine sealant that can be put into use that quickly. If it were me I'd do a "short haul" maybe two days on the hard, take your time and do it right. You don't "have" to through bolt but if you're going to screw or tap the backing plate you'll certainly want new ones. Those look like they have some serious moisture in them but it could be age too..

Even 3M 4200 or (ick) 5200 Fast Cure is 24-48 hours for cure the longer end of that time frame is for colder temps of which 40 degrees is minimum. Beyond that the directions say to "keep away from direct sunlight and RAIN until cured". My guess is that high tide would qualify as a very serious form of rain.. You really ought to short haul to do this right..

By the way some of those valves are quite possibly yellow brass such as that Red-White brand valve. I'd certainly switch those to bronze at the least.....


Multiple heat lamps work well for curing of glass in cold temps but epoxies take a long time, even with fast hardeners, and you'll need multiple coats, fillers, fairing then a seal coat like a barrier coat or gelcoat. While I am crazy, and have done repairs on tide cycles, I would not attempt a full "hole" repair, on the tide, unless it was from a puncture and I was just trying to get it floating again and to a boat yard to do final repairs.



P.S. I'm a displaced Alaskan living in Maine! I was born up in Fairbanks and need to get back there soon...

The concerns:

1) The Gate valve had a sister, installed at the same time, which already failed.

2) Cheap plywood was used for some of the backing plates, which is badly delaminated, moist, and literally falling apart

3) The head suction is most certainly not of marine grade components, and operates with difficulty.

4) The one glassed in pipe nipple has never given me any warm fuzzy feelings. Its sister has been replaced with a slightly better arrangement. Those two incidentally are the ones that appear in the best working condition.

5) I'm planning on taking the boat into COLD ICE FILLED WATER.. don't want to take ANY more chances than I have to! Anyone have experience with ice and SW suction? The only advise I have heard is don't stop.

The bonding you mention isn't advised as per whatever book I read last.. it changes. My understanding is by connecting them you create more potential for corrosion, since they are normally insulated by a fiberglass hull, and therefore have no potential to carry any stray current. However, the newer groco thruhulls come with a bonding screw now on the nut.. almost like they KNOW no one is using a flanged seacock anymore!

Working on the grid is always an interesting way to do bottom work, really makes you get organized and get the work done. I usually start work in the dingy before the tide is out all the way. One good thing, if you mess up you don't sink very far!

Edit:
The "red-white" is actually coming from the holding tank and going to the deck pumpout.. so not a concern.

I wanted to get suggestions for sealant without leading the question, but from what I understand LifeCaulk will actually cure underwater, and if it gets 8 hours or so of airtime I think it might be just fine. I've used it on all my deck fittings with 100% success.. just not sure about thru-hulls.


Here is an example of a "good" day for an activity like this. I need at least 11 foot tide to get on the grid, so on this example I would float the boat on at 1am, get her positioned, start work on the hull (from dingy) at 5am, get her water tight by noon, can't float off until the 3am flood, so finish work between 1700-2000, float off at 3am. Sounds like a PITA but its not bad once you get the hang of it.. and save you a couple hundred in the bank.

This morning I called both 3M and BoatLife and spoke with tech support about cure times & launching. I did this because neither site really specifies launch time's or windows before launch and I would like to add this info to my article. Here's what I was told by each..

BoatLife: When I spoke with boat life they very clearly stated to me that a full cure of between five to seven days with Life Caulk is what they recommend before a launch. The tech support guy would not budge on this point even when I told him 3M 4200 and 5200 will finish curing under water. I could not get him to budge on this and he said tack and cure are two different things and cure times are very dependent on ambient temperature. He also stated that the air & hull temp can't drop below 40 degrees during the cure process and must be perfectly clean before application.

3M: I spoke with Tom about 4200, 5200 and 101. He advised against 101 due to it's very long cure time in a short window situation or regular 5200.

As for 3M 4200 & 5200 Fast Cure he stated that while they will still cure under water they don't advise running the boat, as in water movement over the hull, until cure has been completed because it can erode any sort of fillet or seal thus causing a leak and possibly moisture entrapment. I think a slow motor to your dock would not hurt as he was mostly referencing power boat failures.

3M also stated that a 40 degree minimum of both hull and air temp should be adhered to and that the lower the temperature the longer the cure time. The hull must also be bone dry & free and clear of any paint, dirt or oil when you are applying it.

3M's official policy on underwater use is to let them fully cure but this guy was being quite honest. He did say they have seen failures on quick launches that's why he advised NOT moving the boat after launch (no water flow across the hull).

Again, 3M's OFFICIAL LEGAL STATEMENT POLICY IS TO LET IT FULLY CURE BEFORE LAUNCH. I say this because I don't want people running around saying 3M told me it's perfectly OK to launch in one hour even though it probably is if you're smart about it....

Hope this helps.

P.S. I did not have time to call Sikaflex to see what their policy is yet.

hmmm.... Seems like the little bit of caulk exposed around the very edge of the mushroom would cure tack free rather quickly, providing enough of a seal for the rest of the caulk to cure. Providing there is no movement of the joint I don't see where the problem would be. Fisherman do stuff like this (and complete bottom jobs) all the time up here year round. Their "standards" are a little lower because most of them could care less about appearance or what other yachties are saying about them.. they just need to get out and fish. Wish I new someone with a big trailer and adjustable uprights.. Nothing says trailer sailor like a 15000lb Rawson

Haul the boat; if it is only a "couple hundred" more then it's a no-brainer. Use heat lamps to cure the caulk to be sure that it does not fall below the 40F critical temperature. If they leak or if that hole you want to glass in fails you will have bigger problems than where you are now...

I think you're safe with either of them. Perhaps 3M is more confident in 4200, 5200 as a polyurethane sealant than BoatLife is with Life Calk as a polysulfide sealant. 3M 101 is also one part Polysulfide similar to Life Calk but has a longer cure time than Life Calk does.

Either way both polyurethanes and polysulfides are moisture cure. Obviously Boat Life is not willing nor is 3M, in print, to say "safe to launch in 1 hour".... Not surprising in this litigious society we live in...!

I've launched within a day with Sikaflex 291 and never had a problem..

$500 for 3 days.. Not a drop in the bucket for some of us.
40? once its in the water it is guaranteed never to go below 40 It will be exactly a cozy 43.7

Holy crap that's an expensive short haul! I paid 375.00 for a 6 day short haul this summer for my 36 footer. But then again everything in Alaska is more expensive other than the taxes. Where are you in Alaska?

P.S. If the water temp is 43.7 you're golden!