Minimum thru-hulls?

[TreblePlink]

Hi folks,

In the refit of my Rhodes Venture 28 (similar to a Ranger) I'm converting to a composting head - and I will have a sink.


What is the minimum number of below-the-water-line thru-hulls I can use?

[Pegu Club]

We did much the same on our Bristol 29.9.
We have two sink thru hulls, two cockpit drain thru hulls, a raw water thru hull, one depth finder thru hull, and a knot meter thru hull. We intend to eliminate the knot meter thru hull this winter, being that our chart plotters have a speed over ground function.
We removed the entire marine head system to include the holding tank.
We will have Six thru hulls when we are done. The boat started with eleven thru hulls when we purchased it. The less holes in the hull the better imo.

{ adventuresontheclub.com } You can check out what we have done.

[Suijin]

Originally Posted by Pegu Club

We did much the same on our Bristol 29.9.
We have two sink thru hulls, two cockpit drain thru hulls, a raw water thru hull, one depth finder thru hull, and a knot meter thru hull. We intend to eliminate the knot meter thru hull this winter, being that our chart plotters have a speed over ground function.

Be advised that if you have a wind instrument that show true and apparent wind that eliminating the speed thru the water data will make your true wind speed and tack data inaccurate.

More info on why STW is important:
http://www.ockam.com/docs/WhyPaddles.pdf

That said, there are "all in one" transducers that measure depth/speed/temp so you could eliminate one thu hull that way.

[Pegu Club]

Originally Posted by Suijin

Be advised that if you have a wind instrument that show true and apparent wind that eliminating the speed thru the water data will make your true wind speed inaccurate.

That said, there are "all in one" transducers that measure depth/speed/temp so you could eliminate one thu hull that way.

Yes, we did take note of that, and are likely to go that route. Thanks for the reminder

[HopCar]

I don't worry about the number of thru-hulls below the waterline. I just make sure they are installed correctly. By that I mean a bronze thru hull, a bronze flanged seacock and a thick fiberglass backing plate. I like Groco products but Apollo, Perko and Buck Algonquin are also good.

[Pegu Club]

Originally Posted by HopCar

I don't worry about the number of thru-hulls below the waterline. I just make sure they are installed correctly. By that I mean a bronze thru hull, a bronze flanged seacock and a thick fiberglass backing plate. I like Groco products but Apollo, Perko and Buck Algonquin are also good.

If you are going to have a thru hull that is how you do it, Groco makes good backing blocks as well.

When we replaced all of our thru hulls and seacocks we used bronze the whole way, Groco is quite good.

[Panope]

Originally Posted by TreblePlink

Hi folks,

In the refit of my Rhodes Venture 28 (similar to a Ranger) I'm converting to a composting head - and I will have a sink.


What is the minimum number of below-the-water-line thru-hulls I can use?

None, if you use only fresh water and place a 5 gallon jug under the sink. Empty jug by hand, over the side.

Steve

[Orion Jim]

Originally Posted by HopCar

I don't worry about the number of thru-hulls below the waterline. I just make sure they are installed correctly. By that I mean a bronze thru hull, a bronze flanged seacock and a thick fiberglass backing plate. I like Groco products but Apollo, Perko and Buck Algonquin are also good.

I have OE Spartan seacocks which are still going strong after 34 years. I would reccommend them unreservedly.

[TreblePlink]

Thanks folks.

It sounds like one for saltwater wash, and one for sink drain. My cockpit drains are just above the waterline. And I'll need a transducer too.