Thru Hull Grate?

[ERTF]

Is it necesarry to have a grate over a thru hull for an A/C if it has a basket strainer?

I'm trying to install an alternative air con & the only spare thru hull doesn't have a grate. Idk how common it is, but all the other inlets on my boat have a grate.

 

[O C Diver]

Is it necesarry to have a grate over a thru hull for an A/C if it has a basket strainer?

I'm trying to install an alternative air con & the only spare thru hull doesn't have a grate. Idk how common it is, but all the other inlets on my boat have a grate.

Consider the amount of water flowing through the seacock per month, and depending on your location, it's a multi of all others combined.

Further, if tied to the dock, the risk of picking up marine life and trash (plastic bags are very common) seems to grow versus open moving water.

For my boat, having a very large coarse screen combined with an internal strainer basket was extremely successful. The large course screen kept most marine life out and the large surface area kept things like plastic bags from being sucked against the through hull.

Ted

 

[Davil1]

depends on boating area

Usually is to protect from seagrass, kelp, sargassum.

 

[twistedtree]

depends on boating area

Usually is to protect from seagrass, kelp, sargassum.

And jelly fish

 

[Fleming]

No, it's not necessary. Can be helpful, but it's certainly not necessary and many perfectly functional air conditioners don't have them. Add one later if you want, but don't let it stop you from using that through hull.

 

[hmason]

I don't have an outside grate. Where we are located we pick up a significant amount of crap in the AC strainer. Right now we are plagued with jellyfish. I clean my strainer minimum once a week during the spring/summer and at times more frequently. But, I do have a "system" for cleaning the strainer that makes the job simple and easy.

Here's my system;
Have at the ready the following items:
A jar or bucket that will accommodate the strainer, a container of laundry bleach and a dockside hose with nozzle.

Close the seacock and remove the strainer. Place the strainer in the bucket. Use the dockside hose with a strong stream to remove as much debris as possible. Dump out the water and then cover the strainer with a 50% solution of laundry bleach and water. After 15 to 20 minutes using a pair of rubber gloves remove the strainer from the bleach solution and hose any remaining debris off the strainer. You can use this process with metal strainers or plastic. I have been doing this for years and it is virtually effortless and requires no brushing.

If the basket that the strainer resides in is fouled as well, use a shop vac to remove the water in the basket and put a 50% solution of bleach and water into the strainer basket and let it sit while you clean the strainer. Then use your shop vac to empty the bleach solution out of the strainer basket or open the seacock and let it overflow into the bilge.

If you want to make this job super easy, have a spare strainer handy that you can just pop into the basket and clean the fouled strainer at your leisure. I have been using this process for years and it is virtually fool proof and extremely easy.

If you suspect that something is blocking the through hull under the boat, such as a plastic bag, I have used a technique for that as well. I shut down the air conditioning system, and making sure my boat is securely tied to the dock, I start the engine and place it into reverse. I increase the RPM a bit and the prop wash will generally clear the blockage. It may take a time or two. I have found that it works most of the time.

 

[cafesport]

We have a 2” inlet sans screen 4’ below the water line. It feeds a grocco self cleaning strainer for our ac, generator and an hydraulic cooling pump. Sargassum and jelly fish blooms have not been a problem and the lower flow velocity due to the increased inlet size reduces barnacle grow as well.

 

[Davil1]

depends on boating area

Usually is to protect from seagrass, kelp, sargassum.and jelly fish as mentioned.

perhaps one way to look at is the diameter of the screen holes
If the area you are boating, there is stuff bigger than the diameter of those holes, then you have the answer.

 

[Deano]

The problem I had was barnacles. Had to back wash with muriatic to clean it but not a huge deal.

 

[paulpoz]

Consider the amount of water flowing through the seacock per month, and depending on your location, it's a multi of all others combined.

Further, if tied to the dock, the risk of picking up marine life and trash (plastic bags are very common) seems to grow versus open moving water.

For my boat, having a very large coarse screen combined with an internal strainer basket was extremely successful. The large course screen kept most marine life out and the large surface area kept things like plastic bags from being sucked against the through hull.

View attachment 164824

Ted

By far the best. I have sea strainers inside and nothing has ever made it to them. We have eel grass and it will block the seacock even before it gets to the strainer, even with a slotted strainer. I installed these and never had another problem. These kind of strainers with holes are the best. That's why they are made like that in your sea strainer basket.