Through Hull Advice Needed

[Boathook]

Thanks for that. I’ll phone around tomorrow and see if anyone can supply them as nobody I’ve found actually lists them. Lee San seem to have the largest range available so I’ll try there first.

Tek Tanks has in the past stocked tru design and still seems to.
https://www.tek-tanks.com/trudesign/

 

[Frayed Knot]

Tranona's post is spot on, but in addition it is not possible to protect fittings on two sides of the hull with one anode. An anode needs to 'see' the object it is protecting and ideally be close to it. If it was necessary to protect skin fittings and valves with anodes they would need one per fitting. A good copper alloy, bronze or DZR, needs no protection whatsoever and even standard 60/40 brass fittings, with which most boats were fitted until quite recently, lasted for many years without significant corrosion.

Thanks for that. Yes, I have anodes on both sides of the hull as well as dedicated ones on the prop & bowthruster, all of which waste quite quickly & need replacing annually - hence my concerns. My boat is berthed at the harbour’s edge, next to a steel piled wall & since a large work barge has been placed nearby I’ve noticed an increase in in the wastage which adds to that concern.

 

[VicS]

Thanks for that. Yes, I have anodes on both sides of the hull as well as dedicated ones on the prop & bowthruster, all of which waste quite quickly & need replacing annually - hence my concerns. My boat is berthed at the harbour’s edge, next to a steel piled wall & since a large work barge has been placed nearby I’ve noticed an increase in in the wastage which adds to that concern.

Thanks for that. I’ll phone around tomorrow and see if anyone can supply them as nobody I’ve found actually lists them. Lee San seem to have the largest range available so I’ll try there first.

Tek Tanks has in the past stocked tru design and still seems to.
https://www.tek-tanks.com/trudesign/

What you are looking for is on this page

https://tektanks.wpengine.com/wp-co.../90-Degree-Male-Female-Threaded-Connector.pdf

BUT only suitable for above waterline use. Below the waterline the valve should be directly fitted to the skin fitting.

 

[VicS]

Thanks for that. Yes, I have anodes on both sides of the hull as well as dedicated ones on the prop & bowthruster, all of which waste quite quickly & need replacing annually - hence my concerns. My boat is berthed at the harbour’s edge, next to a steel piled wall & since a large work barge has been placed nearby I’ve noticed an increase in in the wastage which adds to that concern.

If you use shorepower be certain to have a galvanic isolator .

 

[vyv_cox]

If that's the case I'd glass over them and either move above the waterline or just not have deck drains. Decks are self draining as a general rule, cockpits only need drains because they are enclosed. Had I kept my old boat I was going to glass in some pipe to remove all the failure points, that's also an option.

My boat has deck drains because there is a raised toerail all around the deck. Water lies naturally in the midships area and drains through the scuppers. They exit below the water line to avoid unsightly streaks on the topsides. They have been there for many years now, nearly 40, and never given any trouble.

One of them doubles as the exit port for the above-deck bilge pump.

 

[john_morris_uk]

My boat has deck drains because there is a raised toerail all around the deck. Water lies naturally in the midships area and drains through the scuppers. They exit below the water line to avoid unsightly streaks on the topsides. They have been there for many years now, nearly 40, and never given any trouble.

One of them doubles as the exit port for the above-deck bilge pump.

Sounds perfectly ok and very neat.

I’ve noticed that some people seem to have extreme paranoia about skin fittings. One hears stories of people removing them and glassing over the hole. Not sure what they do with grey and black water or where they get seawater from to flush the heads etc.

 

[Tranona]

If that's the case I'd glass over them and either move above the waterline or just not have deck drains. Decks are self draining as a general rule, cockpits only need drains because they are enclosed. Had I kept my old boat I was going to glass in some pipe to remove all the failure points, that's also an option.

The whole point of having them drain below the waterline is to avoid water running down the topsides. Such systems are popular with high class boats as it avoids having slots in the toe rails/bulwarks and the streaks you often see on topsides. Decks are designed so the drains are at the lowest point and the outlets (in this case 45mm) large enough to cope with the volume of water.

 

[ean_p]

But not the same size as the ones the OP has.

I think you'll find 1 1/2" is about the size he wants if his skin fitting is around 45mm. 11/2" BSP being 47.8mm

 

[Tranona]

All good advice, thanks. And yes, I will ignore it! I agree totally re the double clipping but as you say: the surveyor said it, so if anything went seriously wrong I would be in breach of my insurance terms for the sake of about two quid…
Just a thought; if I were to simply replace the gate valve with a DZR ball valve & if you are correct that the elbow is bronze (I think you probably are) would that constitute dissimilar metals in contact?

The bronze and DZR are fine together as they are virtually the same potential and as they are not immersed in seawater together it does not matter anyway. The only part of a through hull that is immersed in seawater is the bronze flange. I expect that gate valve has a bronze body and no signs of corrosion. The weak points on that type of valve are the spindle and the tendency for the plunger to get stuck to the body with deposits. Given that they are open all the time to let the water drain from the deck when you do try to close them the plunger is seized and the spindle can sheer.

On the subject of anodes, what you currently have is normal - those are two of the common situations where they are necessary.

 

[zoidberg]

.....Not sure what they do with grey and black water or where they get seawater from to flush the heads etc.

Must have done the Short Course.
Seemingly never heard of the Grey Bucket and the Black Bucket....

 

[Tranona]

I think you'll find 1 1/2" is about the size he wants if his skin fitting is around 45mm. 11/2" BSP being 47.8mm

You are right - should have looked more closely at the small print on the PDF of the catalogue.

 

[Frayed Knot]

What you are looking for is on this page

https://tektanks.wpengine.com/wp-co.../90-Degree-Male-Female-Threaded-Connector.pdf

BUT only suitable for above waterline use. Below the waterline the valve should be directly fitted to the skin fitting.

View attachment 154969

Life’s never easy is it? Looks like a DZR ball valve it is!

 

[Mistroma]

The Tru Design answer to your need its on page 25 of their catalogue... Tru Design
The 90* Female -male Threaded connector

Yes, I used a 90 deg. elbow last year. Surprised OP hadn't seen one.

I wouldn't bother with Tru-Design for a fitting above the waterline either. Great for heads etc.

 

[ean_p]

What you are looking for is on this page

https://tektanks.wpengine.com/wp-co.../90-Degree-Male-Female-Threaded-Connector.pdf

BUT only suitable for above waterline use. Below the waterline the valve should be directly fitted to the skin fitting.

View attachment 154969

Is this restriction, do we know, because the fitting is 'plastic' or is the restriction that the first thing on the skin fitting shall be a valve regardless of the material of construction?
Either way I think that I'd be inclined to ignore it as long as the fitting ( the bend in this case) was of quality construction.

 

[langstonelayabout]

My only ad vice regarding through hull fittings would be don’t use plastic seacocks or through hull fittings.

 

[ean_p]

My only ad vice regarding through hull fittings would be don’t use plastic seacocks or through hull fittings.

My use of the word 'plastic' in the above post is in specific reference to the TruDesign item under discussion which is in reality a glass-reinforced nylon composite material. Hence why the word plastic was placed in inverted comma's. I believe they ( the TruDesign items ) carry all the required certifications and acceptances of the major approval bodies.
Have you a reason as to why you would advise against them?

 

[john_morris_uk]

Must have done the Short Course.
Seemingly never heard of the Grey Bucket and the Black Bucket....

I did the advanced course where keeping your wife happy with a flushing loo and drains on the sinks along with showers that pump overboard etc are introduced.

 

[zoidberg]

......where keeping your wife happy with a flushing loo and drains on the sinks along with showers that pump overboard etc are introduced.

Time was a couple of Dubonnets and a prawn curry sufficed.

'Nother example of 'Mission Creep'....!

 

[superheat6k]

Forespar Marelon from ASAP Supplies offer composite sea cocks with a 90o outlet. They do not list one with a 32mm / 1 1/4" outlet but I suspect it is part number 3-80124

Forespar | ASAP Supplies

 

[Tranona]

Forespar Marelon from ASAP Supplies offer composite sea cocks with a 90o outlet. They do not list one with a 32mm / 1 1/4" outlet but I suspect it is part number 3-80124

Forespar | ASAP Supplies

If you look at the OPs installation, none of those would fit. Why make things so complicated when the only problem he has is the gate valve is seized (and is not ideal anyway) but the rest of the bronze fittings seem to be in perfect condition after 40 years. Replacement with a DZR ball valve is almost half the cost of a Forespar, and even a bronze one is 20% cheaper and a direct replacement for the current valve.