New hoses for water drain

[BOAT]

I just don't like it - this whole thing bothers me - I do not like putting bolts thru the transom. Thru Hulls are especially problematic on trailer boats because the hulls take so much punishment bouncing down the highway mile after mile.

I also am aware that most of the water induction on these trailer boat thru hulls does not come into the cabin, most of it goes into the laminated layers of the fiberglass around bolts that have become loose from road vibration. That's why I do not like adding more places for glass to delaminate and I don't like covering up the fiberglass with backing so I can't SEE the de-lamination when it happens. I trailer my boat a lot and it has not got past me that every time I trailer down the road I am bouncing 250 pounds up and down on that thin piece of wood fiberglassed into the transom. Lots of stress on those bolts, but I guess so far no one has had any trouble (? right?)

Thru Hulls are especially problematic on trailer boats because the hulls take so much punishment bouncing down the highway mile after mile.

Geeze, this stuff makes me frustrated.

It's bad enough all those bolts for the outboard - but I figured if there were a lot of de-lamination problems there we should have seen some failures by now. I need to think about this.

One thing I have learned over many years about thru hulls, if they ain't leaking, don't fix them so's they DO leak. I sort of hate to touch them.

I think the idea to move the thru hulls to as place above the waterline is one of the best ideas i have read so far.

[paul I]

I also am aware that most of the water induction on these trailer boat thru hulls does not come into the cabin, most of it goes into the laminated layers of the fiberglass around bolts that have become loose from road vibration. That's why I do not like adding more places for glass to delaminate and I don't like covering up the fiberglass with backing so I can't SEE the de-lamination when it happens. I trailer my boat a lot and it has not got past me that every time I trailer down the road I am bouncing 250 pounds up and down on that thin piece of wood fiberglassed into the transom. Lots of stress on those bolts, but I guess so far no one has had any trouble (? right?)

There is wood in the transom of a Mac? really?

[Highlander]

I,d think only if u r using wooden re-enforcing plates I made mine out of alum 1/4" flat bar

J

[Jimmyt]

If you drill where I did, you won’t hit any... some at the motor location on some boats, but I haven’t drilled there yet on my M. If Boat says there’s wood, I’d go with that.

By the way this is my bilge pump through-hull. I haven't relocated the sink/motorwell drain yet...

[yukonbob]

Looks like a perfect spot Jimmy, almost a half inch of solid glass. There is ply in the transom but is in a limited area. Don’t forget Boat that a proper thru hull is under considerable compression and should be installed with a flexible sealant. Aluminium, mixed with stainless/bronze is a bad idea. Aluminium is low on be nobility scale and the will act as a sacrificial anode, more so if you add electricity from your boat or your neighbours.

[Highlander]

Looks like a perfect spot Jimmy, almost a half inch of solid glass. There is ply in the transom but is in a limited area. Don’t forget Boat that a proper thru hull is under considerable compression and should be installed with a flexible sealant. Aluminium, mixed with stainless/bronze is a bad idea. Aluminium is low on be nobility scale and the will act as a sacrificial anode, more so if you add electricity from your boat or your neighbours.

I,m talking about Eng. re -enforcing plates on the inboard side of the transom !
also hydro leakage is not an issue for me as I have installed an galvanic isolator into my hydro system on my boat
J

[yukonbob]

Looks like a perfect spot Jimmy, almost a half inch of solid glass. There is ply in the transom but is in a limited area. Don’t forget Boat that a proper thru hull is under considerable compression and should be installed with a flexible sealant. Aluminium, mixed with stainless/bronze is a bad idea. Aluminium is low on be nobility scale and the will act as a sacrificial anode, more so if you add electricity from your boat or your neighbours.

I,m talking about Eng. re -enforcing plates on the inboard side of the transom !
also hydro leakage is not an issue for me as I have installed an galvanic isolator into my hydro system on my boat
J

Yes but the isolator only interupts bonding from other vessels; unconnected but electrically isolated dissimilar metals such as when having an unbonded thru hull with a brass ball valve; if this setup was bonded the galvanic isolator would protect you from stray current from other boats while connected to AC shore power but if the anode it is attached to was zinc (most brass being 40-60% zinc) the ball valve would decay at the same rate as the sacrificial zinc. If unbonded/unprotected the aluminium becomes the anode as the dissimilar metals (ss transom bolts and aluminium sheet) create an isolated galvanic cell (ie a battery) the further the metals are on the nobility scale the more current it creates and the faster the less Nobel metal wastes. If your zinc is attached to any part of your setup you shouldn’t notice any decay of the alum but may notice faster zinc wastage, make sure you don’t put aluminium anodes on either.

[BOAT]

Looks like a perfect spot Jimmy, almost a half inch of solid glass. There is ply in the transom but is in a limited area. Don’t forget Boat that a proper thru hull is under considerable compression and should be installed with a flexible sealant. Aluminium, mixed with stainless/bronze is a bad idea. Aluminium is low on be nobility scale and the will act as a sacrificial anode, more so if you add electricity from your boat or your neighbours.

I,m talking about Eng. re -enforcing plates on the inboard side of the transom !
also hydro leakage is not an issue for me as I have installed an galvanic isolator into my hydro system on my boat
J

Yes but the isolator only interupts bonding from other vessels; unconnected but electrically isolated dissimilar metals such as when having an unbonded thru hull with a brass ball valve; if this setup was bonded the galvanic isolator would protect you from stray current from other boats while connected to AC shore power but if the anode it is attached to was zinc (most brass being 40-60% zinc) the ball valve would decay at the same rate as the sacrificial zinc. If unbonded/unprotected the aluminium becomes the anode as the dissimilar metals (ss transom bolts and aluminium sheet) create an isolated galvanic cell (ie a battery) the further the metals are on the nobility scale the more current it creates and the faster the less Nobel metal wastes. If your zinc is attached to any part of your setup you shouldn’t notice any decay of the alum but may notice faster zinc wastage, make sure you don’t put aluminium anodes on either.

Yes, and don't forget if the galvanic reaction to the chemical composition is conductive to the other metals that are in adherence to the frequent exposure from dish water it will make your cups and saucers shed charged electrons that can interfere with the metals at the hose barb when connected on any days in June that are not falling on a third or 11th Thursday unless your thru hull is under sufficient PSI to be under water but only long enough to be wet on the FIRST Thursday in August.

[yukonbob]

Yes, and don't forget if the galvanic reaction to the chemical composition is conductive to the other metals that are in adherence to the frequent exposure from dish water it will make your cups and saucers shed charged electrons that can interfere with the metals at the hose barb when connected on any days in June that are not falling on a third or 11th Thursday unless your thru hull is under sufficient PSI to be under water but only long enough to be wet on the FIRST Thursday in August.

Keep laughing Boat but if you remember most peoples thru hull, transom bolts, power trim, including HL’s are below the waterline and are sitting in a very conductive solution. As long as an isolating compound like Tef-gel is used then the electrical connection will be reduced but not fully eleiminated while emersed.
http://www.pcmarinesurveys.com/AC%20DC% ... olysis.htm
http://www.boatus.com/boattech/articles ... rosion.asp
http://www.boatus.com/seaworthy/magazin ... on-101.asp
https://www.bbsc.org.au/resources/Docum ... sy-SYC.pdf
I could keep going.

[BOAT]

It's too hard to understand I can't understand all the gobbledygook and is tefgel like gobbledygook? I thought the gobbledygook was kitty hair, but now hear tef gel?I am afraid to do anything to my sink drain now. I am too scared because of "dissimilar metals" and the Nobel Peace Prize and stuff I don't understand. I don't know what to do now.

[yukonbob]

Put a proper bronze or marelon thru hull and matching valve in and back with epoxy coated wood, grp or stainless backing plate. You can thru bolt or not. You and me are in the same camp when it comes to adding extra bolts through your hull and the useless piece of sh*t that’s there now hasn’t been open off so pretty much anything is a great improvement. I did all 9 on our boat this winter and didnt thru bolt any. The last set wasn’t either and lasted 36 years without incident. The only concern with marelon is UV degradation.

[yukonbob]

As for dissimilar metals, don’t go bolting stainless onto your aluminium mast without isolating the two from each other with for instance say Tefgel, this includes srews, winches, rivets etc, isolate or use an aluminium backing plate as those tend to be cheaper than a new mast.

[BOAT]

The triangle thing with the three holes in it is the thru bolt part I am talking about. That's the part I was not wanting to put bolts in that go all the way thru the hull. I posted that I wanted to just bolt the triangle thing to the backing plate from the inside but some one told me not to do that. The backing plate I was considering was that McMaster Carr stuff that Sumner was using.




I just wanted to put the bolts into the back plate only like this:



I really wanted the stainless part outside but because of Dr. Nobel you said I can't do that - so I need to use bronze on everything - right?

My biggest concern with thru hull fittings is a leak in the in the BLUE portion of hull in the picture above - that's where thru hulls really do their damage - it's not a total failure of the thru hull or a sprung hose or even a busted thru fitting I am worried about - that just makes a flood at your feet and it's easy to see and easy to clean up. The thing that keep me up at night is water getting around the mushroom head and into the actual hull laminate (the blue part in the picture) - that's the "slow death" where one day you have an entire square foot of hull puckered out and delaminated that you can put your foot through because it's been soaking for 2 years and you did not even know it. And God help you if there is any wood in the hull at that point - if there is any wood your cutting out your entire transom to fix that.

The Threads in the mushroom head are perfect little conduits for water to slowly seep through just like a tiny aqueduct - that's why you can't use a threaded barb with a hose and hose clamp - no matter how tight you make the clamp the water will capillary along the threads right past the hose and there will always be a very slow small drip drip drip. Threaded fittings are a real hard thing to seal up - that's why to be water tight they need to be tapered.

You can bolt that triangle thing till the cows come home but it won't make a lick of difference at keeping the water out of the laminate layers if the mushroom head is loos - and the three bolts have zero effect on the security of the mushroom head. That's the part I am stressing over - not the stupid valve or backing plate. Those leaks I can deal with - it's the ones I can't see I'm worried about.

[yukonbob]

You've got it exactly right. You can use stainless or bronze, the two are very close as far as nobility goes, a good bronze is slightly higher, just as strong and will elongate rather than just a complete failure (stainless is more brittle). Bolt through the backing plate only as you've described and as for the skin fitting there is a channel on the hull side that allows for a good bead of sealant, (sikaflex, 5200/4200) pick your poison) . I sanded down below the gel coat/bottom paint, 5200 to the hull (as well as a smear on the exposed laminate of the inside of the hole before installation) cut and sanded the excess, epoxy barrier coated the exposed glass up to the skin fitting (2 coats with sanding) then bottom paint. Even if water gets past the skin fitting the cross section of the laminate is sealed, this could also be done with resin, but I had 5200 and it works just as good. On the SS or bronze, the bronze will go green but a good bronze will outlast you, they find 2000 year old bronze items all the time at the bottom of the ocean, the oldest bronze artifact found was 4000 years old, even ss cant touch that.

[BOAT]

2 thousand year old thru hull fittings, geez - I guess that's why they called it the bronze age.

Okay- I hate the green and I also don't like bronze and brass because it's malleable and can stretch and needs re-tightening every 10 years. That's why most folks use 5200 on bronze; it allows you to maintain the fittings - the stainless is stiffer and does not deform - but if Dr. Noble want's a bronze mushroom on a bronze thru hull I guess i will learn to like green - but I tell you this, there not gonna get me to come back in 2000 years to re-tighten that stupid thing for it's di-yearly maintenance!