Spot the boat component

[MapisM]

In some respects, I agree.
The problem with a/c is that when you are moored, possibly with neighbors whose cabins are astern, and you wish to keep it running during the night, the noise can indeed be annoying for them. And the risk of damaging anything with an u/w outlet doesn't really increase so much, in practice.

It's the way u/w engine exhausts are designed in (most) P boats, that I hate with a passion.
Just look at the old school Riva Bravo previously posted: straight transom exhausts, raw water coming out of it, no need for idle bypass - everything is much simpler and bullet proof, compared with u/w exhausts.
I would trade the theoretical scavenging advantage and the slightly lower noise (irrelevant when helming from the f/b, btw) of u/w exhausts for that much simpler system any day.
The fact that the latter also works as a telltale is just a side show, in this context.

 

[sorabain]

Down, couldn't see any upside of going for back and thought back would look odd when stationery with the AC on. I don't think it will be submerged even with a banked turn.

Did I make the right choice?

your boat might have gone a tiny bit faster if they were pointed backwards

 

[benjenbav]

See....

.

Why would it be pointing at 45°?

Cos it'll dribble when it widdles and at that angle the dribble will clear the fitting itself.

 

[Deleted User YDKXO]

The pumps in a/c should be and invariably are centrifugal pumps, so can run dry 24/7/365. You just don't need a telltale.

Why then do boat manufacturers waste money fitting a telltale?

 

[MapisM]

Why then do boat manufacturers waste money fitting a telltale?

That's a good question indeed. I was aware that there's an above w/l outlet for your a/c pump, but I always thought that it was the main/only one (as I had in my previous boat), before reading from you in this thread that it's just a telltale...

 

[Deleted User YDKXO]

That's a good question indeed. I was aware that there's an above w/l outlet for your a/c pump, but I always thought that it was the main/only one (as I had in my previous boat), before reading from you in this thread that it's just a telltale...

Thats what I thought at first. I did wonder why the flow was such a pathetically small dribble and that made me check the installation out. It was only when I actually looked at the installation that I realised it was only a telltale and not the main outlet!

 

[jfm]

Why then do boat manufacturers waste money fitting a telltale?

I have no idea Deleted User. But for sure the pumps can run dry. I suppose it might be possible, as a long shot, that the compressors maybe do not shut down on overheat through absence of seawater, but that would be odd with a modern compressor.

 

[Deleted User YDKXO]

I have no idea Deleted User. But for sure the pumps can run dry. I suppose it might be possible, as a long shot, that the compressors maybe do not shut down on overheat through absence of seawater, but that would be odd with a modern compressor.

I'm no expert on centrifugal pumps and I'm sure you know more than I do but I find it hard to believe that a centrifugal pump is capable of running 24/7/365 totally dry. Surely the impellor bearings/seals and shaft seals just overheat and fail eventually?

 

[MapisM]

No expert either, but as I recall from the only pump I ever took apart (several years ago), I don't think any of its parts relied on the water flow for cooling. In fact, any heat-generating parts on the electric side were definitely air cooled.
Besides, the load on the motor is obviously lower when the pump runs dry, so I wouldn't be surprised if someone with a proper engineering competence on these pumps should tell us that they run cooler when the pump is dry...