Thru-hull size

[osprey877]

I would llike to add a new thru hull to my 40' s/v to service a water maker and deck wash pump. I'm thinking of using a Marelon seacock for the through hull. They come in a variety of sizes, starting at 1/2" and going up from there. What size is adequate for my intended use? I can't find any postings or web info on this issue. Thanks.

[skipmac]

First, demand from the watermaker wouldn't require a large hose or high flow rate. I would be the manual for the watermaker has something on this.

I'm guessing you wouldn't generally run both at the same time so I would size the through hull for the deck washdown pump.

Unless you have a monster firehose sized pump I would think 1/2" - 3/4" would be sufficient. Certainly no larger than 1". What size connections are on the pump? That should tell you something as well.

[Cheechako]

Yeah, 3/4 would be fine . I doubt there's much $ penalty over the 1/2"

[osprey877]

I think I'll go with the 3/4" as suggested. Thanks for help.

[zboss]

If you are getting a water maker, are you getting one big enough to allow you to use fresh water for your washdown? That is my goal - to have enough water to periodically wash down the boat with fresh water while on the hook.

Then, you would only need one hole in the boat.

[osprey877]

Zboss: I'm planning on only one hole. It will supply both the watermaker and the saltwater washdown pump.

[zboss]

Originally Posted by osprey877

Zboss: I'm planning on only one hole. It will supply both the watermaker and the saltwater washdown pump.

The reason I mention this is because you are not supposed to share the watermaker through hull with anything else.

I suppose its probably done regularly but manufacturers say its a no-no.

We have a salt water washdown but no watermaker - yet.