SO43DS - removing thru-hulls

[andreshs1]

hi there

has anyone ever thought how to reduce the number of thru-hulls on the boat?

I currently have 16 active thru-hulls...
I have tried merging the shower drain with the sink, but now when draining the shower the sound in the sink is really loud. 

Has anyone considered running the sink and shower drains to the bilge?

Cheers

[saltymetals]

Hi Andres.
An interesting idea. That would eliminate 2 through hulls. Presumably you would do it with a tube down to the bilge. So the shower would then self drain rather than needing to press the switch to activate the pump during a shower.

I like to try and keep my bilge as clan as poss so dont like the idea of soapy scum and hair pouring into the bilge so have not gone ahead with your interesting idea. I added a timed relay on my shower switch so it just takes a quick flip of the switch which activates the pump for 40 seconds. Did the same for the forward head. I hated the need to stand , all soaped up, in the shower , having to hold my finger on the wretched pump switch. Now it is the occasional quick flip and forget.
Andrew

[andreshs1]

Hi Andrew

Yes, I also have the delay switches installed, yet, I am keen on reducing the number of thru-hulls, as the boat looks like a Swiss cheese. and doing this would remove 4 thru-hulls (2 in each head)

I am thinking on fitting a hose directly to the bilge sump, to avoid water all around the bilges and add a strainer, to keep hair from reaching the bilge pump

the only concern is the foam forming on the side of the hull when the admiral or the kids shower, (3 women requiring a sizeable amount of shampoo and conditioner...) there would be lots of foam forming on the side of the boat

cheers

[rxc]

I have thought about this because I agree with you about having too many holes in the boat. The AMEL people have a long pipe seachest in the boat from which the various services take water. Only one valve to open/close. For discharge, I don't know what they do, but I would not dump anything in the bilge. The drains from any sink or the shower have too much organic material that would eventually stink, so you really need a dedicated tank with a pump, just like a holding tank. Probably with an automatic macerator pump. Your neighbors might complain, though, when they see what you are pumping out into the waters...

I considered installing two seachests - one back aft for the main engine, genset, and saltwater system pump. The existing thruhull for the main engine looks like it might be great for a large seachest.

Another one fwd would serve the watermaker, Aircon, and seawater supply to the fwd head. I already have a thruhull there for this application, with a plumbing "tree", which is generally not considered a good idea, but it does function like the AMEL linear seachest.

The reason you need a seachest, instead of just sharing a thruhull, is that if one services sucks too hard it can pull a vacuum or drain one of the other services. I had this happen to me on my previous boat, where I shared the main engine thruhull with a salt water washdown system, and had to install a check valve, which is also not considered to be quite seaworthy. The thruhull was a bit small, because the engine was small, and the saltwater washdown pump moved a LOT more water than the engine did.

[andreshs1]

Hi there

what volume should each of the seachests have?

Cheers

[rxc]

I can't give you any estimate of the size. I have browsed seachests in equipment catalogues, and if I bought one from a dealer, it would be the biggest one I could fit, at a price I was comfortable with. They do take up a bit of space, which is why they work, and you have to have a large enough hole in the boat to service all the sea water services you have attached.

The Amel idea is very attractive, but those boats were designed with these linear seachests in mind, so they have spaces dedicated to them. I saw a long discussion about them on the Amel site about a year ago, which was fascinating.

Take a look at this page, which will give you some ideas:

amelyachtowners.groups.io/g/main/topic/sea_chest/77367440?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,20,77367440

[andreshs1]

Hi RCX

thanks for the link, very informative

out of curiosity, as we have the same boat model, which sea-chest model did you buy?
what are you going to use it for?

on my side, if I could reduce the number of thru-hulls by 50% would be extraordinary

I am thinking on fitting 2:
- one for the engine & generator, with a feed to the head (I have never ran the engine & generator at the same time, and the toilet does not require high volume of water when used, thus should not be an issue)
- one for the A/C, fwd head and washdown pump

that would only leave the discharge thru-hulls to deal with in the future


cheers

[rxc]

I don't have any seachests. I sometimes wish I did, but have not had any problems, yet, with the two "trees" that I have set up. I would worry about tapping the genset into the main engine thru-hull without making the hole in the boat larger, because I think it might drain the strainer and maybe even quite a bit of the hose back to the pump, and even back into the engine. I have a new tree on the genset thruhull to support the new Frigoboat fridge pump and am actually worried about it. I rarely use the genset and I think I might have to install a shutoff valve for the genset feed from the tree. The fridge pump will operate intermittently, outomatically, so it needs to be open all the time. When the new compressor arrives, I will have to see what happens if they both operate at the same time.

Up forward, the thru hull for the aircon units also feeds the watermaker. The watermaker is in storage until we go somewhere that we need to use it, and it is isolated from the tree. I think I ran both of them in Bermuda while at anchor, and don't remember any problems.