Replacing skin fitting with different size

[Gixer]

So my current engine raw water intake in about 10 years old so I'm going to replace it with a new one. I've decided on a Trudesign system (why not?) and am going to buy the normal skin fitting rather than a scooped/grated one like I have now.
My engine needs a 1/2 inch (1GM10) but I could fit a larger size inlet if I'm replacing the lot. Question is, is there any downside to fitting a slightly larger fitting. More likely to clog, water turbulence?
I am planning to keep the boat and I 'might' fit a larger engine at some point, although unlikely.
Interested in your thoughts

 

[Elessar]

I see no harm in it at all. I would have gone trudesign but they are not allowed in the machinery space of a coded boat.

 

[RJJ]

Turbulence. It will slow you down by about 0.00001 of a knot.

I can't see the downside. Of course you won't get any additional water flow....that will be determined by the bottleneck, wherever in the system that occurs.

What's the benefit? Do you know what engine you "might" upgrade to, and what water intake it wants?

 

[Gixer]

Turbulence. It will slow you down by about 0.00001 of a knot.
What's the benefit? Do you know what engine you "might" upgrade to, and what water intake it wants?

I meant turbulence to the water flow inside the seacock creating a back flow or something (i'm over thinking it...)

I keep looking at a Beta 14hp which uses a 3/4in inlet.

 

[Norman_E]

No downside at all. When I replaced my skin fittings I also used Trudesign. You need to ensure that you can clear any obstruction, for example if a plastic bag gets sucked in. My method was to fit a tee piece directly above the sea cock, and take the cooling water from the tee, with a vertical standpipe fitted with a removeable cap so that I could rod right through the seacock and skin fitting in need.

 

[Gixer]

Great idea Norman. Thank you.

 

[Tranona]

I meant turbulence to the water flow inside the seacock creating a back flow or something (i'm over thinking it...)

I keep looking at a Beta 14hp which uses a 3/4in inlet.

That is because of the larger capacity and greater flow rate of the freshwater cooled Beta. Really no need for a 3/4" for a 1GM. nor any need for a Trudesign. a DZR 1/2" skin fitting valve and tail will be fine. Change it when you fit the Beta and try to locate it immediately below your strainer - that is what I did when I replaced a 1GM with a Nanni 14.

 

[Gixer]

Thanks Tranona, what you suggest is pretty much what I have now although my strainer is connected to the top of my ball valve.

 

[Tranona]

Chances are that is actually bronze so really no need to replace it. Bronze and DZR last effectively forever provided you exercise the valve regularly.

 

[Gixer]

The fitting and ball valve are DZR, I bought and fitted myself. Why have I got it in my head that they should be replaced after 10 years??

 

[Tranona]

The fitting and ball valve are DZR, I bought and fitted myself. Why have I got it in my head that they should be replaced after 10 years??

Probably because you have heard the nonsense about "5 years" which comes from the RCD requirement that through hulls should have a MINIMUM life of 5 years. Even plain brass which the vast majority of new boats use lasts far longer than this, and DZR should not suffer any corrosion at all.

 

[vyv_cox]

The fitting and ball valve are DZR, I bought and fitted myself. Why have I got it in my head that they should be replaced after 10 years??

A certain surveyor who features in the magazines seems not to know the difference between brass and DZR. Some of his advice on lifetimes is confusing.

 

[Spirit (of Glenans)]

No downside at all. When I replaced my skin fittings I also used Trudesign. You need to ensure that you can clear any obstruction, for example if a plastic bag gets sucked in. My method was to fit a tee piece directly above the sea cock, and take the cooling water from the tee, with a vertical standpipe fitted with a removeable cap so that I could rod right through the seacock and skin fitting in need.

Maybe I'm reading your post incorrectly, but it's my impression that you hope to rod it through a right-angle . It would be better to route the water through the leg of the 'T' , with the standpipe attached to the crossbar, and with a gentle curve bringing it to the vertical. A flexible plastic rod or thick cable can then be used for clearing obstructions.

 

[lustyd]

I see no harm in it at all. I would have gone trudesign but they are not allowed in the machinery space of a coded boat.

I seem to recall this has changed and they are now allowed. There’s certainly no downside to having a composite one in the composite floor of your composite boat, so I think it was just a case of getting approval, as any new type of fitting would need.

 

[RJJ]

Probably because you have heard the nonsense about "5 years" which comes from the RCD requirement that through hulls should have a MINIMUM life of 5 years. Even plain brass which the vast majority of new boats use lasts far longer than this, and DZR should not suffer any corrosion at all.

If it's DZR I would keep it.

If there's any doubt it might be brass or have brass innards, change it. I did mine age 13 and they were scary.

 

[Tranona]

If it's DZR I would keep it.

If there's any doubt it might be brass or have brass innards, change it. I did mine age 13 and they were scary.

See post#10. All is good one horrible job not needed and £100+ saved!

 

[Elessar]

I seem to recall this has changed and they are now allowed. There’s certainly no downside to having a composite one in the composite floor of your composite boat, so I think it was just a case of getting approval, as any new type of fitting would need.

It would be annoying if that’s true as I replaced all 8 seacocks a year ago - at that point the surveyor told me I couldn’t have composite.
Agreed 100% ii is/was an illogical rule. The log fitting is composite and OK!

 

[lustyd]

It would be annoying if that’s true as I replaced all 8 seacocks a year ago - at that point the surveyor told me I couldn’t have composite.
Agreed 100% ii is/was an illogical rule. The log fitting is composite and OK!

I wouldn't assume that surveyors would be up to date. When we do ours I'll be contacting TruDesign in the first instance and working back from there. If we weren't on a long trip right now I'd go and find the thread but for now definitely assume I made it up just in case!

 

[Norman_E]

Maybe I'm reading your post incorrectly, but it's my impression that you hope to rod it through a right-angle . It would be better to route the water through the leg of the 'T' , with the standpipe attached to the crossbar, and with a gentle curve bringing it to the vertical. A flexible plastic rod or thick cable can then be used for clearing obstructions.

No, You can rod straight down, using a broom handle or anything of similar size to clear any obstruction. The cooling water goes off at a right angle with an absolutely straight pipe down through the sea cock.

 

[vyv_cox]

No, You can rod straight down, using a broom handle or anything of similar size to clear any obstruction. The cooling water goes off at a right angle with an absolutely straight pipe down through the sea cock.

When we transited the Canal du Midi our engine seacock blocked with leaves about 100 times. At the time we had an old strainer immediately above the ball valve with a T off for the supply. I could close the valve, remove the cap, insert a brazing rod, open the valve and rod through, closing the valve as the rod was withdrawn. By the time we emerged into the Med I could do it in about a minute.