Install mid ship hatch open forward or backwards ?

[arch007]

Going to install a midship hatch on a 28 ft sailboat.

1. Should hatch open forwards ?

Bow hatch opens forwards. Con easier for waves to wash in ?

Also pros and cons of a midship hatch such as another escape route ?

Any advice ?

Thanks.

[SV Siren]

personally I prefer mine to be facing forward, to pull in airflow. Closing and locking down the hatch should mitigate any concerns of water intrusion.

[tkeithlu]

Open to scoop in air at anchor, batten down at sea, as SV Siren suggests. Only the other way around if you anchor under really unpleasant conditions...

The big advantage is going to be airflow, which to me is really valuable. Muggy stale air in a cabin is not pleasant, sea breezes are.

[Alan Mighty]

Originally Posted by arch007

1. Should hatch open forwards ?

Bow hatch opens forwards.

Depends on the structure of your vessel and its below deck spaces.

For many (but not all) aft-cockpit monohulls, when sitting at anchor (i.e. sitting to the wind, with the bow to windward and the stern to leeward), the ventilation below decks will enter at the cockpit and exit at the bow. By which I mean that the ventilation flow below deck is contrary to the direction of flow of the wind.

If that were the case, a forward hatch (either at the bow or midships, depending on how your spaces are arranged) should open aft.

Note the importance of that "depends".

You need to explore your vessel sitting at anchor and discover the natural flow of ventilation below decks. And then work to accentuate that natural flow, not fight against it.

[psk125]

Opening forward will help airflow. The companionway (exhaust) hatch is likely much bigger than the forward and midship hatches combined, so you want to push as much air as possible into the cabin. It will all go out the back. You can also have the midships hatch open at times when spray forces you to close the forward one.

[DefinitelyMe]

In general boats built for cold climates have hatches facing aft and those for the tropics face forward, so it kind of depends on where you are. At sea once you start taking water over your midships hatches they will be closed whichever way they are facing so forward or aft makes not much difference. Besides, if you have forward -facing hatches you can still mitigate risk of taking on water by only opening them a crack whereas you'd have to open an aft-facing hatch much wider to achieve the same airflow.

You can use wind scoops to help get more air into an aft-facing hatch at anchor but they are not always practical.

Sometimes an aft-facing hatch makes sense if it is restricted by the vang.

Not advice as such. The choice is of course yours. Just a few points to consider.

Personally, outside of high latitudes the only reason I can see for having an aft-facing hatch is on a race boat where you can ship a lot of water through the forward hatch when moving sails in and out of it. An aft-facing hatch in that case can help to reduce water coming in by providing a bit of a barrier to green water over the bow. But it doesn't really apply to cruising boats in the same way.

[arch007]

Thanks for everyone's help.

[KadeyKrogen38]

My preference is for a hatch that is double hinged meaning you can choose to open forward or aft by just moving hinge pins. All four of my Bomar hatches are double hinged.

[Scubaseas]

Forward. You want positive pressure in the saloon. Open facing forward forces air into the cabin. Aft facing will want to pull air into the saloon from cockpit/aft of boat. You do not want to pull exhaust into the cockpit or saloon. Think about air flow both at anchor and while motoring.

https://www.practical-sailor.com/boa...lmost-any-boat

Do you have other vents on the boat?

[jim King]

90% of the time you will have the hatch open will be at anchor. Having the new hatch open forward will draw much more air in and cool you of (especially in the tropics). Just got back from 8 days sailing n Belize. With forward opening hatches we seldom needed the AC even with night temperatures in the 80s. While at anchor you will mostly be facing into the oncoming winds which will flow down into the the forward opening hatches. While motoring or sailing we always close the hatches to mitigate any splash from swells.
cheers,

[roverhi]

For a midship hatch opening aft to create a negative pressure area that will suck air out of the boat. If you make up side curtains/hood you can leave it open in even pretty snotty conditions. Studies on houses show that having more area to exhaust air creates more air movement than the other way round.

[Mlp48]

A midship hatch with dodger over that I've experienced has brought in air and kept the area dry -- even with some green water.

[Knotical]

Our boat came with a midship hatch that opens forward. In benign conditions we keep it open while sailing and it ensures a nice breeze down below. The forward hatch cannot stay open under sail as it catches the Genoa sheets. Another advantage is the airflow directs the galley fumes out the companion way, we don’t have an opening port light over the galley so that’s really important.

[Knotical]

Originally Posted by Alan Mighty

For many (but not all) aft-cockpit monohulls, when sitting at anchor (i.e. sitting to the wind, with the bow to windward and the stern to leeward), the ventilation below decks will enter at the cockpit and exit at the bow. By which I mean that the ventilation flow below deck is contrary to the direction of flow of the wind.

Alan, I am curious about this thought - I have been on several boats and whenever the forward facing hatch is open I always feel the wind coming from the bow going towards the back, I have never felt the “reverse” (this is only on boats on swing moorings or at anchor).

[JPA Cate]

Our galley hatch opens aft, and the midships hatch and forehatch open forward. We have dorades that also ventilate the saloon, which are pretty easy to turn forwards, to the side, or aft. We live at anchor, and rarely go in marinas, and when we do, we look for upwind slips. But you really have to take whatever they have to rent you, and being able to let some air in, even if it comes from the side is way better than not.

As the OP can see, most people have their hatches forward facing. I wonder if Kadey Krogan 38 could tell us how often he changes and which ones he changes the direction on his boat, in his usage.

For us, especially in hot weather, having the [aft facing] galley hatch open, helps a huge lot with helping remove cooking heat....but, there is also an opening port above the stove, which does its share, too.

Ann