Deck scupper size

[DinghySailor]

Hi all, in my 4 years cruising our C&C 37, I’ve yet to be disappointed with performance, save for some squirrly runs. I am frustrated though with the inadequate scuppers on deck. The 3/4” drain holes are incapable of evacuating large amounts of water. Has anyone replaced these with larger fittings and if so, do the hoses also need sizing up?

 

[kappykaplan]

do the hoses also need sizing up?

What size are the existing hoses?

 

[DinghySailor]

Believe the they’re 1.5”. Checking later today.

 

[FastOlson]

The 3/4” drain holes

Where is this fitting draining from? Deck? Cockpit sole?

 

[MFD]

I agree that 3/4” is really small.

A good reference point for items like this is the offshore racing regulations - either category 1 offshore or category 2 nearshore would be good depending on the type of sailing you do.

IIRC, the drainage requirement is based off the volume of water that the cockpit can hold if a big green sea poops the boat and turns it into a bathtub. Basically how fast can the boat dump all the water - hopefully before the next big wave hits.

Many years ago I had to substantially increase the pair of scuppers we had on a 30-footer to meet category 1 for the Vic-Maui. I think they originally were also 3/4 I updated to 1.5. They drained out the transom like 4-8” above the waterline and would make an interesting gurgling sound when a following sea would rise above that.

anyway - the race regs are always a good reference point.

 

[DinghySailor]

Where is this fitting draining from? Deck? Cockpit sole?

As mentioned, these are on deck intended for water over gunnel. Not talking about cockpit drains—they function well with volume. Talking about side decks, low end of sheer. Gutter extends forward about 8’

 

[MFD]

For some reason I thought you were referring to cockpit scuppers.

If these are on the deck and just drainage from deck out the bulwark instead of full cutouts, then they are probably fine for their job. Get rid of rain water or a little bit of leftover seawater?

I have been on two C&C 37s off and on over the years and don’t recall significant deck bulwarks or drainage. Definitely will be looking next time (late this summer) when I on one again!

 

[DinghySailor]

We’re inner-coastal on the Salish, but we do run into steep stuff in the straits. We want to head to SE AK, circum Van isle, maybe run down coast, etc.

Deck scupper hoses are 3/4” ID terminating in an adapter on the seacock that can be replaced with 1.5” fitting/hose. I guess the only question is finding the a deck scupper fitting to accommodate 1.5” hose and the opening on deck. Ideas?

 

[jssailem]

The term deck scupper hose is confusing. The C&C 37’s, I have seen were built using an aluminum toe rail on a flat deck. Water on the deck just washes off.

The cockpit is of good size. And I can see the use of a deck scupper as necessary to empty the water that comes aboard. In that case the 3/4” diameter hoses and fittings would be undersized.

I would look to a 1.5” deck scupper, a full flow 90 and 1.5 smooth hose or pvc pipe to a thru-hull above the waterline.

There are other designs but this is a typical example.

 

[PaulK]

Maybe you should try to not get so much water on deck? 3/4" should be plenty for clearing spray. Heavier waves should mostly overflow the gutter/toerail and go overboard anyway. Maybe the drains were designed to be smaller so that water on deck would find its way mostly over the rail. What benefit is clearing the 1" of water that remains twice as quickly as before? Is your rail meat complaining of wet bottoms? This is not a safety issue like making sure the cockpit clears before the next wave fills it completely and it sinks the boat. Having to do deck surgery to install an opening twice as big is not going to be fun, easy, or cheap. Why are you contemplating this?