First thru-hull fittings

[CCwoodenboat]

Yikes. Gotta drill through the hull for the first time. Cockpit scuppers just above the waterline. 1.5 inch perko scuppers with new bal-check valves. I plan on crossing the pipes (port scupper to stbd hull ad vice versa). Four big questions on this nervous mission:

1: are seakocks advisable/common on projects like this?
2: I hear exhaust tubing is th best for a project like this, but what kind of exhaust tubing?
3: how the hell do you drill and make watertight a bronze thru-hull?
4: are regular stainless hose clamps enough to fasten the tubing to the male ends of the supper and thru-hull?

Correction: 5
5: what other questions should I be asking?

[wizbang 13]

Aw geeze, just talking about this a little over on the " no bridge deck" thread.
http://forum.woodenboat.com/showthre...No-Bridge-Deck

[Roger Cumming]

#1: Yes.
#2: Exhaust tubing to differentiate it from lighter weight, less strong hose.
#3: The bronze through-hull fitting screws into the seacock. I don't know what a bal-check valve is. You need a seacock. A wood backing plate larger than the base of the seacock is through bolted to the planking. The through-hull fitting is installed from the outside of the hull through the planking, through the backing plate and into the seacock. The seacock is bolted through the backing plate and the planking.
#4: S.S. hose clamps (doubled) are standard for attaching the hose to the fitting.
#5: Where to locate fitting? Must be accessible to easily get at hoses and clamps, to remove drain plugs for winter storage and to disassemble the seacock for servicing.

[Peter Malcolm Jardine]

Above waterline scuppers (on a powerboat) do not require a seacock. The check valve is enough. I assume you have the Perko chrome on bronze scuppers. They are a very good fitting. Exhaust hose or Engine water hose both meet ABYC standard for scuppers. Use a mushroom head drain fitting for the through hull fitting. Bed it well. I am also assuming this is a powerboat, otherwise the seacock requirement comes into play.

[Bob Cleek]

An article in WB a couple of issues back covered through hulls and seacocks in depth. Recommended reading.

[CCwoodenboat]

Moving forward with the scupper assembly. forum still won't let me post images to http://provincetownwoodenboat.blogspot.com.

http://4.bp.blogspot.com/-0i2ao8SBSp...oto%5B1%5D.JPG

Preliminary scupper assembly:

1.5" apollo bronze mushroom thru-hull with 3" threaded
to
1.5" apollo ball-valve,
to
bronze barbed step-down pipe-to-hose fitting (1.5" outer diameter to 1.5" id)
to
1.5" id exhaust hose stainless steel double clamped
to
perko 1.5" scupper drain with check ball ss double clamped.

the exhaust hose in the picture is a short piece for photo purposes.

Bottom of cockpit is 13" above the waterline with the scupper location 35" inboard of the hull at deck-level - in that case i am considering running hoses port-to-port and stbd-stbd, instead of criscrossing.

I am concerned about location of the thru-hull - is a large rise important running from the thru-hull to the cockpit to ensure adequate drainage? without the crisscross there will be abt a 33" straight run of hose (minus several inches added for the curve) - if the rise is 4" i'll have the thru-hull 8.5" above the waterline.

Biggest concern is that the seacock isn't flanged - it seems like using the seacock lever, or any bump on the adapter/seacock/thru-hull assembly on the interior will laterally torque the thru-hull seal. i have no sense of the strength but looking at this seacock assembly which will stick out of the interior hull at least 7" makes me think that it could get bumped and mess up the thru-hull's seal.

How do we look? what do we need to change? Thanks everyone.

[CCwoodenboat]

Bad link - heres the blog woth photos:

http://provincetownwoodenboat.blogspot.com/

[kc8pql]

This it?

[Breakaway]

Ok. Here's the deal. You have a ball valve and a through hull on the seaward end, not a seacock..So do lots of boats. I'll try to explain the subtle difference.

Through hull threads are straight; ball valve threads are tapered. So while they appear to fit together, the threads arent locking together correctly. A flanged seacock has straight threads that match those of through hulls.

Additionally, a flanged seacock is held to the boat by screws through the flange. The arrangement you have, there is nothing to stop the through-hull from turning when you throw the handle.

Your setup will work, and does work for many.

But were I you, I would go the flanged seacock route. After all its a one time job, so why not cross all the Tees and dot all the ayes.?

Here is what a "proper" flanged seacock looks like:




Kevin

ETA: Other advantages of a proper seacock are:

1. Has drain plugs

2. Has grease fitting

3. Square hole in handle allows you to use a socket wrench ( without a socket installed) to extend your reach to operate the lever

4. If it ever gets stepped on, its stronger


K

[Peter Malcolm Jardine]

Ummm... Did everyone miss the fact that this is:

1. A powerboat
2. drains from the cockpit contained above the waterline
3. the cockpit is not self contained, so half the water ends up in the bilge
4. ABYC standards do not require power boats to have a valve on above waterline drains.

[Breakaway]

Looks like a sailboat on his blog....but if that's incorrect,than yeah, I missed it.

Kevin

[CCwoodenboat]

36' peterson schooner. The cockpit is 14" above the lwl, and the drains will be above the waterline as well. The cockpit is self-contained.


On my way to getting seacocks as i noticed both the tapered thread issue and the greater stability of having a bolted seacock instead of s free valve. I see many seacock installations bolted with drifts instead of through-bolts. Drifts seem to offer fewer holes and a cleaner exterior but id feel more comfortable with something i can really bolt down.