Through deck fittings for control lines

[RoyB]

For a 31 foot frac rigged asymmetric inshore race boat I am considering running the new two ended backstay controls under deck and out again near the traveller. The reason is to avoid more stuff underfoot for the helmsperson to trip over in the cockpit.

The only sticking point is that I don't know the best way to seal up the penetrations so that 3/16 spectra double braid can pass through with a minimum of moisture.

The cockpit is always dry except for spray, rainy days and boatwashing. The boat doesn't go offshore so oceangoing seaworthiness isn't mandated. If I do have penetrations in the cockpit sidewalls I'll make some quick-install protective covers that are truly waterproof just in case.

I know that nothing I can fabricate will be completely waterproof . I've considered making some tightish leather or rubber seals with rope-sized openings.

Surely there's a correct way to do this? Anyone aware of a commercial fitting for this application that actually works?

[cyclops]

Rubber or whatever. Grommets that are a draggy fit is as good as it is worth.

[JPC]

I know I've seen commercial fittings for this -UHMWPE material, e.g. that is very low friction if your lead is reasonably fair. I did a quick look, but my feeble memory didn't send me to the right place - I'll keep an eye out.

Are you planning to run tubing under-deck between the entry and exit, or were you going to mount blocks? How's your access to that under-deck area?

If you're relying on the UHMWPE material to serve as a block in part, I'd recommend stripping the cover off as much of the line as possible (unless it's coated core, which can be pretty sticky)

In addition to hardware suppliers, you might find answers/ideas amongst the boat groups that use these fittings (Farr 40, Swan 45, etc.)

[JPC]

My point is-

I wouldn't try to keep water out of the holes; just try to control it when it enters by enclosing the under-deck route from entry to exit.

[yokebutt]

Roy,

Have a look at any of the newer race-boats, especially the main-sheet setup. They often use a recessed mount for the turning block where the line runs through a hose to the exit block.

Yoke.

[SuperPiper]

Have you considered Liqui-Tite flexible conduit and bulkhead fittings?

[arjan]

I am looking at the same thing for a catamaran and I am contemplating using thru-hull fittings that way I can seal the deck and the opening can be 1/4" above the deck

[JPC]

Roy,

Harken -and, I'm sure, others- make blocks specific to your application (e.g. addressing the need to make a 90-degree turn immediately under the deck).

[tspeer]

I'd keep the control lines on the "outside". If you put in a tube sealed to the boat at both ends and run the lines through that, you don't actually have a through-hull. You just have a more complicated shape to the deck. The tubes should also be arranged so the water can drain out and not collect in them.

[ErminoMazzarino]

Roy,

How would you get the rubber or leather to not move in the hole.? Also, you will need a roller of sorts to reduce friction and chafing of rope. I agree with yokebutt, look at the new race boats. They have the new tech. Good luck.

Ermino Mazzarino

[SailDesign]

The simple way is to make a trough in the deck, then screw (not glue) a thin-but-strong cover on it, allowing you to go in and clean or fix something if it (when it...) goes wrong.
That way the line is still "outside" the boat, but not capable of being tripped over.
Steve

[ErminoMazzarino]

Steve,

Good Idea, PVC or ABS could be used. Drill a large hole at top and smaller hole at bottom for screw. This would also allow for drainage. Thanks.

[RoyB]

Thanks for all the good suggestions. I'll be walking the club docks tomorrow to spy on the newer high tech boats.

Since I posted the question I've figured out a way to run the lines above deck in a cockpit corner where they'll be out of the way so that simple method may win out

[ErminoMazzarino]

Hi Roy,
The K.I.S.S. principle wines out again, that's gratifing. Have fun working on your boat and smooth sailing. ..Ermino