Deck drain/scupper/hose/hull penetration/sinking?

edwardh1

Petty Officer 2nd Class
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Nov 26, 2003
Messages
137
I looked at a high end outboard, new, 18 ft dual console boat yesterday that had the double wall/full flotation construction.

The inside cockpit floor at the rear on the floor had a drain on each side.
the drain hose went below the floor to the transom , with the exit below the water line. Inside the transom of course you had a hose going from the transom hole up to the deck drain.
It seems to me if the hose fails the water will come into the boat- is this common, or do other deck drains drain out above the waterline where it would be safe?
 

Fireman431

Rear Admiral
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Sep 17, 2007
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4,292
Re: Deck drain/scupper/hose/hull penetration/sinking?

Depends on how low below the waterline the drains are. It works on head pressure. If the pressure of the water coming from the deck drains are greater than the pressure of the water over the exit ports, the water will drain out.

I'm sure their set-up works. I can't imagine that they developed this system without ever putting a boat in the water to test it.

You also have to look at the construction of the hose and fittings. If it a heavy gauge hose with a helix embedded, you will probably have a 20+ year life span on it.
 

25thmustang

Lieutenant Commander
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Mar 20, 2008
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1,849
Re: Deck drain/scupper/hose/hull penetration/sinking?

My boat actually has a scupper loacted right at the water line. I believe it sits in the water, at least to some extent. With that said, my hose connections are above the waterline. The Internal part at the scupper is a molded F/G box of sorts, and the water drains down into it. If the hose failed, water would not come in. Water has no problem going out though.

With regards to the hose connection being below the water line, I would be leary of this. I like to check my engine compartment a lot, and always look for things amiss, but when I leave the boat, I like knowing something as simple as a scupper won't sink it.

Personally I would look for a way to revamp the connections, and try and get the hose clamp portion up higher. If not, my .02 would have me looking for a different boat.
 

roozter2550

Petty Officer 3rd Class
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May 14, 2009
Messages
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Re: Deck drain/scupper/hose/hull penetration/sinking?

In the quest for more gunnel/cockpit height, many times the cockpit drains end up below the waterline.
It's not the most common practice, but not exactly rare either.

My cockpit drains have float balls in them to prevent water from coming in and lead to thru hulls below the water line.
I just finished changing all the below waterline thru hulls with stainless fittings...(the plastic ones were original from 1998 and I didn't want to use plastic again.)

livewell drains...1-1/8" 90 elbow x 2 fittings
sink drain...3/4" 90 elbow x 1 fitting
deck drains...1-1/2" 90 elbow x 2 fittings

Manufacturers use plastic for below the waterline because of cost reasons.
I spent approx $300 on the 5 fittings I replaced.
 

dingbat

Supreme Mariner
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Nov 20, 2001
Messages
15,417
Re: Deck drain/scupper/hose/hull penetration/sinking?

IManufacturers use plastic for below the waterline because of cost reasons.
I spent approx $300 on the 5 fittings I replaced.

Not exactly.

Stainless suffers badly from crevice corrosion. Elbows and other areas with stagnat water are problem areas. I'd keep an eye on those elbows and drains if you used stainless in those locations. If you don't feel safe with "plastic", bronze would have been a better choice in those locations.

I replaced all my internal fittings with Maralon. No corrosion problems, will last the life of the boat.
 

ufm82

Master Chief Petty Officer
Joined
Jul 29, 2003
Messages
827
Re: Deck drain/scupper/hose/hull penetration/sinking?

My ProLine has the same floor drains but they are above the waterline or below the waterline depending on how much weight I have in the boat. If I have 5 people on board and a full tank of fuel, the drains are underwater. If it's just me and a 1/2 a tank of fuel, they're above it. I do have the issue of water coming up though the drains when they are submerged and actually e-mailed ProLine about this issue. They told me that some people installed check valves in the hoses to prevent backflow and some people simply didn't care and let their feet get wet. I replaced all the thru-hulls with new ones two years ago and looked for some check valves to put in but all have a spring of some sort and the water pressure from the floor to the outside didn't have enough pressure to open the valve to drain. So now when I know I may have a backflow issue I stick a couple rubber plugs in the floor drains so no water comes in. Seems silly to have to do that but it beats getting wet feet when wet feet aren't desired.

However, as stated above, if the hose is good there is no pressure there and they will last a long, long time.
UFM82
 

dingbat

Supreme Mariner
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Nov 20, 2001
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15,417
Re: Deck drain/scupper/hose/hull penetration/sinking?

I have scupper both fore and aft in the cockpit. The water line is right in the middle of each.

Sometimes I'll get a bit of water in fore scuppers when running a heavy beam sea. Not enough to get your feet wet.

The aft scuppers have always been dry. Nothing but the black rubber flappers in use. It wasn't a probem in my last boat either.
 

roozter2550

Petty Officer 3rd Class
Joined
May 14, 2009
Messages
92
Re: Deck drain/scupper/hose/hull penetration/sinking?

Not exactly.

Stainless suffers badly from crevice corrosion. Elbows and other areas with stagnat water are problem areas. I'd keep an eye on those elbows and drains if you used stainless in those locations. If you don't feel safe with "plastic", bronze would have been a better choice in those locations.

I replaced all my internal fittings with Maralon. No corrosion problems, will last the life of the boat.

I couldn't find bronze 1-1/2 90's like I needed in bronze and would have to piece fittings together to make straight thru hulls work so I decided to go with the stainless on all and not mix-n-match metals. I could have used marelon but being a trailered boat which is kept under cover and dry, the stainless should outlast the boat.
 

seabob4

Lieutenant Commander
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Jun 10, 2008
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1,603
Re: Deck drain/scupper/hose/hull penetration/sinking?

Any hull penetration that is below he waterline MUST be bronze, SS, or Marelon. That being said, builders try to get as much freeboard as they can, yet still maintain the self-bailing cockpit. In their test conditions, they say the t/hulls are above the waterline, therefore the below the waterline requirements don't have to be met. Therefore, cockpit drains will be at the waterline under the best of conditions. Throw in some serious weight, and they go under water. That's the deal, you guys know me, I work in the business.

T-H Marine In-line Scuppers are a good product to add if you're getting too much water back on the deck when the drain t/hulls are submerged...
 

GatorMike

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Aug 3, 2003
Messages
902
Re: Deck drain/scupper/hose/hull penetration/sinking?

Those cockpit scuppers are probably the T-H scuppers others have mentioned. They have a check valve in them to keep water from flowing backwards, even so I can't imagine the outlets being installed under the water line. The check valve is just a simple floating ball. Anyway over at the Wellcraft board I have posted many threads with pictures about these scuppers and some of the problems with the way Wellcraft used them in at least one of their models.

Here is one of the threads. There are several others if you search for them.
http://forums.iboats.com/showthread.php?t=223871
 

edwardh1

Petty Officer 2nd Class
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Nov 26, 2003
Messages
137
Re: Deck drain/scupper/hose/hull penetration/sinking?

yes thru hull holes were only about 4 inche above the hull bottom.
 

GatorMike

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Aug 3, 2003
Messages
902
Re: Deck drain/scupper/hose/hull penetration/sinking?

yes thru hull holes were only about 4 inche above the hull bottom.

It makes me wonder if maybe there isn't a weight problem there somewhere. Water logged floatation foam or maybe an engine that is heavier than the boat was designed for. I just see no advantage to those holes being below the water line.

Someone mentioned useing a heavy hose to connect the scupper to the drain hole. This can be a mistake. Over on the Wellcraft boards several people with their 190 fisherman series have complained about excessive water in the bilge. Their problem is that T-H scupper is connected to the drain hole with a very rigid hose. When the hull flexes something has to give. Over time the weak link is the scupper drain. I have replaced mine twice and instructed others on the site to replace theirs. I reciently put a more flexible hose between the two. In my opinion this was a design flaw that Wellcraft had in that model.

PS once the scupper breaks you get water in your bilge both from the deck and the drain hole. Even if the drain hole is above the water line. A lot of water can splash in an open hole at the waterline.
 

edwardh1

Petty Officer 2nd Class
Joined
Nov 26, 2003
Messages
137
Re: Deck drain/scupper/hose/hull penetration/sinking?

the reason I think the transome holes are so low is that if they were at water level, the cockpit drains would not drain (builder wants a deeper interior, floor to top of gunnel.
 

seabob4

Lieutenant Commander
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Jun 10, 2008
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1,603
Re: Deck drain/scupper/hose/hull penetration/sinking?

One of the tests we have to do is to load the boat to it's rated capacity, evenly distributed, then shift the weight in the cockpit to induce a 7 degree list. If the waterline stays below the t/hull opening, the NMMA requirements are met and the t/hulls do not have to be Bronze, SS, or Marelon.

The problem with boats is that they absorb water in a variety of ways as they get older. Hence they get heavier, and thus sit lower in the water. So when the boat was new, your 2 Bubba BILs could sit at the stern and move about, and you'd be alright. 10 years later? The t/hulls are under water...
 

dingbat

Supreme Mariner
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Nov 20, 2001
Messages
15,417
Re: Deck drain/scupper/hose/hull penetration/sinking?

Someone mentioned useing a heavy hose to connect the scupper to the drain hole. This can be a mistake. Over on the Wellcraft boards several people with their 190 fisherman series have complained about excessive water in the bilge. Their problem is that T-H scupper is connected to the drain hole with a very rigid hose. When the hull flexes something has to give. Over time the weak link is the scupper drain. I have replaced mine twice and instructed others on the site to replace theirs. I reciently put a more flexible hose between the two. In my opinion this was a design flaw that Wellcraft had in that model.

Rigid hose or not, sounds like the T-H scuppers are junk.

I still have the OEM scuppers in my boat after 13 years. I took them out two years ago to change the caulking and they were still in good condition. Rigid hose and all.
 

Philster

Captain
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Sep 15, 2009
Messages
3,342
Re: Deck drain/scupper/hose/hull penetration/sinking?

My buddy's 26' (I think it's 26) Fountain Center Console w/ newer Yammy 250 capsized at the dock when this type of setup (fitting) failed.

Insurance company says, "Hey! We no pay, because we don't cover those fittings! Here's the highlighted portion of the policy!"

That was May. Now, August is here... and he hired an insurance adjuster in June. Might have some resolution by Christmas. The latest is that the insurance company isn't blinking. I believe he is out around 25,000 bucks (approx value of boat), plus the cost of the adjuster.

Ain't boating fun?!
 
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