I started to pull the thru-hulls in anticipation that it's getting warmer and i'll be able to replace them all with proper groco seacocks. four of the thru-hulls came out surprisingly easy.
however, i can't seem to get the raw water strainer off. there are four screws at the corners that poke through the hull and into the head compartment. I've removed the nuts and tried banging on them with a hammer. the didn't even budge backwards a nanometer. i then tried hammering a wide flat putty knife between the hull and the strainer. sadly no joy
am i doing something fundamentally wrong or did i miss a step in removing the strainer? i don't plan to put it back, so i'm not above damaging it, but i don't want to if i don't have to and i don't want to damage the hull. so even though i was hammering on it, i stopped short of "hey this might break something" level of force.
the pictures are from the survey, I've already removed the hoses and marelon seacocks...
on a separate but related note, I'm a little perplexed by the sizes of the thru-hulls. it looks like to me the macerator, head/kitchen sink drains are 3/4", the toilet intake and raw water intake are 1/2". since groco doesn't make a 1/2" assembly, is there any issue with enlarging all the holes to 3/4" or should i go larger on any of them?
Md : Looks to me like you are going to have to chisel off that outside strainer that a PO put on. I'll guess that it might even be caulked on the seams?
Have you tried taking a wooden dowel and hitting it from the inside to drive it off?
A thought
Quote from: Ron Hill on February 11, 2018, 02:40:28 PM
I'll guess that it might even be caulked on the seams?
Have you tried taking a wooden dowel and hitting it from the inside to drive it off?
i didn't see any adhesive, but i wouldn't shocked if there isn't 5200 under it somewhere. i had thought about the dowel. unfortunately i didn't have one and i figured before i went to town on it i'd see if i was doing something stupid. i'll give it a whirl next weekend.
For what it's worth you appear to have ball valves threaded onto the thru hulls, not seacocks. A traditional seacock is a 90 degree rotation ball valve with an integrated flange that attaches it to the hull (or backing plate) and the thru hull threads into it.
Although it's unlikely that anyone could apply excessive pressure onto the hoses on those thru hulls below the bathroom cabinet, it's still a good idea to do it right.
http://www.pbase.com/mainecruising/backing_blocks (http://www.pbase.com/mainecruising/backing_blocks)
Paul
Quote from: Jon W on February 11, 2018, 05:03:48 PM
For what it's worth you appear to have ball valves threaded onto the thru hulls, not seacocks. A traditional seacock is a 90 degree rotation ball valve with an integrated flange that attaches it to the hull (or backing plate) and the thru hull threads into it.
Yup, that's only the tip of the iceberg of scary stuff i've found as i tear through this (new to me) boat. all the thru-hulls are getting replaced with proper groco sea cocks. the picture was merely to show the bolts. all the marelon and dry rotted hoses are already gone...
Md :You'll have to remove the hose in the picture and then unscrew the all valve so you can then use a 3/8" wooden dowel and try to drive off that strainer.
If everything comes off down to the thru hull itself you might be able to use a 1/2" dowel.
A thought
Marelon flanged seacocks are a good product. One of the first things I did was remove all the ball valves and thru hulls then replaced them with Marelon flanged seacocks mounted to backing plates. Flanged bronze seacocks are also a good product, but require bonding and also run the rare risk of blowing out of the hull if the boat is struck by lightning.
I second Jon's interest in Marelon. I know bronze has historical precedence and is the proven metal, but I'm all into reducing as much metal below the waterline as possible. This might be a personal bias since as a teen I remember being hit by lightning, and in that case what saved us was the large twin bronze grounding plates that all the standing rigging was attached to. After that, I research all about lighting, grounding and bonding. The less metal below means less maintenance of a bonding system. IMO, perhaps others think differently.
I certainly don't have enough knowledge to be for or against marelon for any technical material reason. I read way too much on the internet and have heard the good and the bad of both marelon and bronze. so here's how I personally made the decision, this is just my opinion:
1. cost was close, assuming one piece with flange and valve (the split flange/valve is slightly more expensive)
2. i like that the bronze comes in a flange and a separate valve, means not having to disturb the thru hull if a valve freezes up
3. i like that groco sells backing blocks, i could order a sheet of G10, but once i did, bought tools, and cut circles, it was roughly the same cost
4. bronze has a slightly longer history, small advantage, but newer isn't always better
5. mainesail endorsed! :)
the last and biggest came down to, I just don't like the way the marelon feels. to me, even though i totally know it isn't, it feels like cheap chinese junk you'd get at walmart. i know that's a totally unfounded irrational feeling, but it would keep me up at night worrying about whether my boat is sinking...
Staying out of the bronze vs. Marelon fray, but have a question: are you going with flush or mushroom thru-hulls? If flush, how do you plan to match/deal with the bevel in the hull? New thru-hulls/seacocks are on my list for my next haul out in May.
There are copy products out there that imply they are Marelon, but they aren't. If it's Marelon it says it on the part. Much of the Marelon poor test results is with a ball valve threaded onto a thru hull, not a Marelon flanged seacock attached to a backing plate. End of the day you're right, it's what you are comfortable with. Remember bronze contains zinc. Stray current and salt water should drive a good bonding/earthing design.
Quote from: Noah on February 13, 2018, 08:16:07 PM
Staying out of the bronze vs. Marelon fray, but have a question: are you going with flush or mushroom thru-hulls? If flush, how do you plan to match/deal with the bevel in the hull? New thru-hulls/seacocks are on my list for my next haul out in May.
I have recently added a thru-hull, in the v-berth, for the Air Conditioning Raw Water intake. I purchased a mushroom thru hull, but screwed up and had to go to WM to get a replacement, they only had the flush mount.
To match the bevel, I used a 1/2" belt sander very judiciously, it took me about an hour to cut the bevel in the hull (solid, not cored).
I have to think that someone has come up with a suitably angled countersink to do the job in a few seconds.
Paul
Quote from: Noah on February 13, 2018, 08:16:07 PM
Staying out of the bronze vs. Marelon fray, but have a question: are you going with flush or mushroom thru-hulls? If flush, how do you plan to match/deal with the bevel in the hull? New thru-hulls/seacocks are on my list for my next haul out in May.
my hull currently has all flush thru-hulls. i couldn't say whether this is standard or not. unfortunately groco doesn't list the bevel angle or the distance from the shaft to the bevel. it seems foolish to think the marelon ones i removed and the new bronzes are a match.
after i get some measurements, if they match then i'll put flush ones back in. which kind of stinks because the groco flush mounts are more expensive then the mushroom ones. i'll probably pick up one of each, test fit them, and try to see if there is any impending disasters. i'm really trying not to have to pay the fiberglass guy to re-fare the hull for any reason. hopefully it'll all just work!
i hope to have the flush/mushroom question answered this week, i'll report back. it was only just warm enough this past weekend for me to even get down to the boat and pull the old ones out.
nuts... apparently the marelon thru-hulls have a much larger flange. now i'm soliciting opinions on the best course of action.
I'm with you domenico! I was thinking of starting to gradually replace my through hulls, but I didn't have any interest in fibreglass work to fair the hull to match the smaller flanges so I have left them as is. My half hearted internet search for extra wide flange through hulls from a few years ago didn't yield any positive results. I will be keen to see if others have a source for the wide flange through hulls.
poking around the internet it looks like buck algonquin makes a 3/4" bronze flush thru hull that has a 2-1/2" flange. the marelon flanges come in at 66mm or ~2-5/8" , there might end up being a 1/16" gap between the seat of the flange and the hull. i'm not sure if that's okay or not, there's usually some squeeze out of glue, presumably the glue will fill that void
i ordered one to see how it fits in the hull and whether it'll thread cleanly into a groco flange. if it works, that'd be great. if not, i'm worried my only options are to either get new marelon fittings or fair the hull smooth and use mushrooms. my confidence with fairing the hull is pretty low, but i'll have to 'internet it' and see what is really involved in filling a big hole.
nothings been fitted to the hull yet, if anyone see big red warnings signs, please let me know.
Mideomenco- sorry you are having valve fit problems. Thought that might be a issue when I asked in a previous post about how you were going to deal with the taper (flush fit). I am looking to replace my thru hulls and valves as well, but don't have the advantage of being on the hard for a extended time. I have to orchestrate all bits and pieces prior to haul out. I am considering Forespar Marelon OEM Series 93 over standard Marelon flange with backing plate—decided against bronze. In either case, knowing the outside diameter of my various flush through hulls would be a plus in planning/ordering parts ahead of time. What is the diameter measurement of your existing Marelon flush tapered flange/heads? Do they match the current available Marelon flush head size(s)? Or will you still need to fill, drill, regrind, etc.?
Hi Noah,
I think he said the the flange OD was 66mm (2 5/8") which is consistent with what I measured a few years ago. This pic shows the head sink drain. It would be great if there was a readily available source for Marelon wide flanges.
By the way... I love your comment "...don't have the advantage of being on the hard for an extended time." What a polite dig at us northern sailors who have the privilege of carefully examining our hulls on the hard for months at a time while some poor sailors such as yourself have to sail your boats all 12 months of the year! :rolling :rolling
Quote from: Noah on February 24, 2018, 06:48:58 PM
What is the diameter measurement of your existing Marelon flush tapered flange/heads? Do they match the current available Marelon flush head size(s)? Or will you still need to fill, drill, regrind, etc.?
the outer diameter of my old marelon fittings is 2.66in for both the 1/2" and 3/4" fittings. it's hard for me to say whether new forespar fittings are a direct fit without actually having one. if we look at the chart they show, for series 250 fittings, different measurements for 1/2" and 3/4". mine are not. the 1/2" and 3/4" flanges are exactly the same, they only varied the threaded portion in diameter.
this is probably because the originals are not from "forespar" but rather have stamped on them "r.c. marine". according to the history page at forespar, forespar bought the tooling from rc marine in the 80's. if i had to guess as forespar got smarter in making the parts they re-tooled at some point and changed all the dimensions from the rc marine originals. if that were true, depending on how detailed the records are at catalina, i'd bet they could tell us exactly when that happened, as i imagine they would have had to modify the hull mold.
anyhow, using just the 3/4" fittings as an example my outer diameter (value A) is 2.66in or 2-5/8", the chart for a 3/4" thru shows 2.43in or 2-1/2" at first blush this might not be an issue at all, maybe some space for the glue to seep out and form a good bond.
the groco bronze fitting is 2", so that gap is much to large to fill with glue. i'm hoping the buck alonquin fitting at 2-1/2" will fill the gap enough that sika-flex will take up the 1/16" gap around the fitting and all will be good. i suspect the same "working theory" could apply to the marelon fittings
or it could be a disaster, i have no idea.
Thx guys! Good info. My "out of the water comment" wasn't a passive aggressive dig. Really! It cuts two ways. Yesterday I was crunched up in the forepeak changing the anchor locker drain hose and instead of the hose coming off, the old nylon thru-hull at the bootstripe snapped off! :cry4` Today, I will be installing a new marelon one. In the water! How? Maybe laying face down, on the dock?, in a dinghy?, who knows...? But right now I am seeing daylight and water! BTW- Ron, it is a 3/4 in thru-hull, not 1/2 in. !
Noah : If it is a 3/4"OD thru hull, the ID might only allow a 1/2" dowel?
A thought
Continuing to highjack this thread, sorry. Successfully installed my anchor locker drain thru hull at the boottop/waterline. I used Marelon to replace the busted nylon one.
The thru hull is 3/4 and barbs to use a 3/4 ID hose.
My plan was to back the boat into my slip and hang off the dock to reach the thru-hull but, it was blowing 20 kits— too risky with almost no daylight between the two boats. So I pulled my bow over to his stern, catty corner in the slip, and hung off his swim step. Went pretty quickly with me on the inside of boat and my son-in-law holding thru-hull from turning outside, with an improvised too; a cold chisel with Vice Grips clamped on as a handle.
Quote from: Noah on February 26, 2018, 03:32:34 PM
Continuing to highjack this thread, sorry. Successfully installed my anchor locker drain thru hull at the boottop/waterline. I used Marelon to replace the busted nylon one.
actually it's okay, those pics were helpful, the anchor locker is next on my list. my thru-hull there is busted off on the outside and the locker is full of leaves and crap. all happened before i bought the boat. but the pics at least let me see what i'm in store for... :)
Great pictures Noah. Thanks. I sometimes lie awake at night thinking of ways my boat could sink. The anchor locker drain low at the bow and the bilge pump discharge fitting low at the stern both come up frequently. I think I'll order the appropriate through hulls and some hose so I can get going on those two jobs while I can do the work at convenient shoulder height on dry land. :wink:
even though i run the risk of totally jinx'ing it. i think I have a solution. the Buck Alonquin thru-hull arrived today and it's actually like 1/32" or 1/64" larger then the marelon one. it seems to thread in the groco flange just fine. so, this might just work out...
in fact, i just measured the differences with a micrometer. the BA thru-hull is ~1mm larger in diameter and it's ~1.5mm thicker in the flange over the marelon one. so all in all, should be pretty close fit or at least close enough...
Nice! Do the bevels match for all your thru hull sizes?
Quote from: Noah on February 27, 2018, 04:28:55 PM
Nice! Do the bevels match for all your thru hull sizes?
they're close. the marelon (from forespar) bevel is shown at 53 degrees, the BA is shown at 45 degrees. i'm hoping that since the BA thru-hull has a shallower angle that the small gap difference will just fill in with sikaflex. i'll be down at the boat this weekend, I'll know pretty quick if it doesn't fit, here's hoping...
looks like we might have a fairly decent fit. seems to line up pretty well around the flange. i still have some sanding to do to remove the excess caulk and paint still in there. but a little cleanup of the holes and i think we'll have a "good enough" fit.