Mixing bronze and marelon

windrose · Post by **windrose** » Tue Jan 16, 2007 10:26 am

Is it OK to use a bronze mushroom piece and use a marelon sea cock or should these be one or the other.

I am finally installing a deck wash for this Chesapeake mud. It gets in the boat and stinks things up as the rode comes back aboard. Yesterday I cut a hole in my boat forward of the wet locker in the v berth. The core was a little over 1 1/4" and it was a beast to cut thru. From here I will supply water to the deck wash and a raw water foot pump in the galley. I am wondering if this should have a strainer on it as we have lots of sea nettles on the Chesapeake, any thoughts on this?

It was 70* here yesterday and the boat yard was a buzz of activity.

I have decided against removing the ice box for now, too much to do! (especially after I read about Tim and Nathan removing Nathans'!) So yesterday I added spray foam all around the existing ice box in areas I could not reach and added 2" of rigid insulation to all the areas I could reach. Removed the old latches to the cockpit opening and am adding insulation to the lid and better latches and gaskets to the door and the cockpit lid.

Figment · Post by **Figment** » Tue Jan 16, 2007 10:56 am

When Forespar first kicked off this whole Marelon product line, they prohibited mixing with bronze, but their advertisements now clearly state "can be used with bronze".

Where does the science end and the marketing begin?

Though I haven't mixed the two myself, as long as you're careful not to cross-thread and bugger up the plastic, I don't see any problem.

Post by **Tim** » Tue Jan 16, 2007 11:39 am

Despite an apparent softening of the "don't mix the materials" thing, I'd still be inclined to stick with all bronze, or all Marelon in any single installation.

Whether it's OK or not, we know that bronze on bronze is OK, and Marelon on Marelon is OK. Lacking a truly compelling reason to mix the two, I wouldn't. Just in case.

Yankee conservatism may be boring, but it avoids undue problems.

Ceasar Choppy · Post by **Ceasar Choppy** » Tue Jan 16, 2007 11:52 am

Nigel Caulder discusses this in his book, although I think the discussion is the more general use of plastic fittings with bronze... from what I remember, it it more appropriate to use a male plastic fitting in a female bronze fitting than the other way around. Has to do with the dissimilar rates of expansion, and more importantly, the mating threads. You need to be VERY careful not to mess up the threads on the plastic fittting with the much sharper/harder threads of the bronze fitting.

bcooke · Post by **bcooke** » Tue Jan 16, 2007 1:50 pm

I am curious. Why would you choose to mix materials between the seacock and thru-hull? Are we wading through the scrap bins here?...

Don't be put off by Tim's and Nathan's attempt at removing the icebox. They are pansies. It comes out in about ten minutes with an appropriate sized hammer. Swing for the fences.

A deck wash sounds nice. I almost plumbed one in while I was working on some other plumbing but I got distracted. One question. How do you control your boat, raise the anchor, and clean the rode simultaneously? I can do two out of three okay but the third makes it tricky for me. What I want to figure out is how to direct a fixed high pressure spray at the rode right at the roller so that I can just hoist away and know the rode is being cleaned as it comes in automatically. Wishful thinking probably.

-Britton

Post by **dasein668** » Tue Jan 16, 2007 2:22 pm

It's really not the "getting out" that is the issue, though if you still have an interior that you want to keep somewhat intact, the "swing for the fences" technique might not be optimal.

But building a new box is a bigger job than it seems at first blush.

bcooke · Post by **bcooke** » Tue Jan 16, 2007 2:53 pm

Nathan wrote:But building a new box is a bigger job than it seems at first blush

Now there is something we can agree on :-)

catamount · Post by **catamount** » Tue Jan 16, 2007 5:07 pm

My boat came with several bronze thru-hulls with Marelon valves attached. Seems to have worked fine, and raised no issues in my survey. That said, these were all on 3/4" pipe size thru-hulls. I don't know if they were original to the boat, although I suspect they do go back quite a few years. The 1-1/2" pipe size thru-hulls still had the original gate valves (which were an issue with the survey).

dmairspotter · Post by **dmairspotter** » Tue Jan 16, 2007 6:41 pm

I have used bronze through hulls and Marelon seacocks on my two last boats.

My reasoning is that the through hull will probably see the most abrasion/rough handling, so I go with bronze. I like the non corrosion aspect of the Marelon so I go with that for the bit with the moving parts.

I have also done my share of cursing at all metal through hull/seacock combinations that have welded themselves in place on old boats.

I fail to see any merit in the different expansion coefficient argument. The range of temperatures experienced is not wide, especially when the boat is in the water. Anyone care to calculate what the change in the diameter of a two inch through-hull would be with a 30 degree change in temperature?

Anyway I have never had a problem with the combo, nor have I ever had cause to need to service a Marelon seacock, so I'm happy with it.

Figment · Post by **Figment** » Tue Jan 16, 2007 7:12 pm

dmairspotter wrote: Anyone care to calculate what the change in the diameter of a two inch through-hull would be with a 30 degree change in temperature?

dusting off the 100-degree thermal expansion coefficients stashed in a cloudy back corner of my brain...
0.0020 inches in aluminum
0.0016inches in steel
0.0018 inches in bronze.

There is something very wrong with me.

windrose · Post by **windrose** » Fri Jan 19, 2007 8:47 am

Thanks guys. Any thoughts on putting a stainer on the intake for nettles or will they simply get minced up in the pump. If they do get minced in the pump will the tentacles still sting when they come thru the raw water at the sink? I assume it is an allergic reaction. What have other Chesapeake sailors done.... should I even worry about it?

Thanks again.
Ang

Ceasar Choppy · Post by **Ceasar Choppy** » Fri Jan 19, 2007 12:24 pm

If you have room for it, an inboard strainer helps.

Last year I sucked up a monster jellyfish in Solomons in my air conditioning intake on the hottest day of the year. Haven't had a problem with the engine intake-- YET. Its good insurance.

Duncan · Post by **Duncan** » Sat Jan 20, 2007 9:25 am

bcooke wrote: How do you control your boat, raise the anchor, and clean the rode simultaneously? I can do two out of three okay but the third makes it tricky for me.

I take up the rode in stages, wait for the boat to go forward, and splash the rode around when it's slack. "Repeat as necessary". Doesn't take very much longer, and gets to be a habit.
As long as it's not blowing too hard and there's a little sea room, a quick couple of bucketsful before going back aft takes care of anything that made it aboard.

bcooke · Post by **bcooke** » Sat Jan 20, 2007 9:54 pm

I don't know about the jellyfish in your area but my experience is that jellyfish continue to sting even after they have been minced up.

-Britton

windrose · Post by **windrose** » Sun Jan 21, 2007 11:20 am

I put a nice micron filter on the fresh water foot pump, I am thinking I will add one of those little cheap in line screen filters on the raw water side before the pump. My thoughts are, it will keep some of the trash out of the raw water pump and hopefully keep any tentacles out of the galley area.

The jelly fish here, commonly called nettles, don't have a wicked sting. It is more like being stung by several "sweat bees" at once. However, if we don't have very much rain in spring and the salinity in the water gets high they become a real nuisance because their numbers explode. You know when you jump in the water you are going to be stung, it is just a question of when and WHERE. YIKES! Designated swim areas have what is known as a nettle net to keep them out of the swim area, but when it is hot and there is no wind....