How important are opening portholes?

[Lonewolf]

Hi there,

My search for a boat is on going and I'm trying to determine how important opening portholes should be as a liveaboard.

I'm aware that condensation/moisture build up is a serious matter on boats and I'm placing a high priority on minimizing this. The first things I'll be doing is lining the hull with insulation and installing a diesel heater if it does not have one.

I'm curious about ventilation recently as I see a lot of boats for sale that have very few opening ports, if any at all, just the opening hatches. I cant seem to find any answers on this topic so far. My gut feeling is that it's probably a big deal, just looking for some first hand experience to confirm or deny my suspicions. How much value should I be putting into opening portholes?

[a64pilot]

For me, it’s a big deal.
Ventilation, as much as you can get is a big deal for me, but I’m wanting to cool off, you sound like your somewhere cold, for you it may be good not to have opening ports
Mine are heavy SS, and being heavy metal in cold weather they stay cold, and drip moisture inside, so for cold weather it may be better not to have them.

[Matt Johnson]

We had them on the last, but opted out of installing them on the current. We only used the opening ports in a marina when the only wind available was from the beam. If at anchor, the deck hatches give a much better breeze overall.

Matt

[Lonewolf]

Yes the winters here are cold and wet, but we also get pretty hot summers so it would be nice for then too.

I'm just concerned about moisture not being able to escape, like when I'm cooking or have a rare shower aboard, even just breathing.

I do plan to run the diesel heater 24/7 once winter comes so keeping the metal portholes warm may reduce the condensation there, or maybe plastic fittings would be advantageous, despite the obvious drawbacks.

[billknny]

The answer is, like almost everything boating, "It Depends"

If you spend much of your time at anchor with the boat weathercocked into the wind, then opening ports on the sides of the cabin do very little, and the overhead hatches do all of your air exchange.

In a marina, where the wind can come from random directions relative to the boat, the side ports are more important.

There are very well ventilated boats with few opening side ports, and very poorly ventilated ones with many opening side ports. Ventilation is a dynamic process, and it can take time to figure out what works on individual boats.

[Matt Johnson]

Do the boats have dorade vents? They were much more important for our usage since they get airflow regardless of what the weather was like outside.

Matt

[Lonewolf]

Originally Posted by funjohnson

Do the boats have dorade vents? They were much more important for our usage since they get airflow regardless of what the weather was like outside.

Matt

Ah so that's what those vents are called, I'll keep a closer eye out for those when looking at boats if they play a critical role in ventilation.

Sounds like hatches and dorade vents are much more important than portholes.

[El Pinguino]

I have 6 opening windows on my boat.... they have not been opened in at least 20 years... apart from the time I rebedded them.

They are a pest... being much harder to double glaze than my fixed windows due to the knobby bits that hold them shut.

Double glazing to stop condensation on alloy window frames is easy.... cling film or bubble wrap with a bit of door 'draught excluder' to hold it clear of the alloy.... secure it with double sided tape. Fit it on a cold dry day. Not pretty but it works....

[Classicsailboat]

I had 9 opening portholes and could adjust them depending upon conditions. I would not want only fixed portholes.

[roland stockham]

Overhead vents are more efficient for circulating air and cooling the boat plus less prone to leaking. There are places on some boats where they may be the ideal answer but generally would avoid them. Inefficient and expensive.

[Seighlor]

Living in Florida, ventilation has long been a big factor to me. As has been pointed out, hatches provide your best source. Dorade's, in my view, may be your only ventilation option when sailing in bad weather. Other than that, I consider them to offer a minimal enhancement to free air flow.

True, opening ports are at their best when tied to a dock and wind is on the beam. I still consider them an enhancement to the overall flow of air, adding to the draft created by open hatches. In other words, I love 'em.

[AJ_n_Audrey]

I agree with others that when at anchor opening ports make little difference, since airflow through the main hatches is massively greater, but in a marina I'm glad to have them. Also, I have one opening port in the head which is good for venting and for drying the shower on the rare occasions when it is used. I installed an additional Caframo fan next to one of the opening ports and when the wind is right it really accelerates airflow in the cabin. It's a near thing, but I think if I had it to do over I would still install the opening ports (NFM ports, btw).

I have one dorade, original to the boat, but I cannot sense much airflow through it, and I have yet to disassemble it to see if there is a hidden issue, but it's on my list. Oh, and there is a solar-powered Vetus fan that a PO installed through the main cabin hatch, and that's nice for maintaining airflow when the boat is closed up.

[Stu Jackson]

My experiences have been a goodly mixture of many of the points made so far.


Our boat has eight opening ports plus one smaller one in the head; six in the saloon and V berth on the cabintop sides and two in the aft cabin opening to the cockpit footwell. We have two cowl vents (not truly dorades) that can be opened and closed; I leave them open all the time. There's a saloon hatch and a V berth hatch.



I have rarely opened the cabintop ports. The head port stays open unless it's raining or winter! Nice weather opens the V berth hatch and the saloon hatch. The aft cabin ports are left open in the summer, closed in winter. They are Beckson ports, with the head one being a Gray.


The dodger I find is indispensable for ventilation. Our two earlier boats didn't have them. Without a dodger the companionway must be closed up in questionable weather, whereas with a dodger, unless it's raining sideways from aft (!) it can be left open during the day.


Essentially we operate our saloon and V berth ports as if they were fixed, the rest are used.


The cowl vents provide the ventilation when it's cooler outside.


I would rank them as: dodger, cowl vents, selected opening ports, all opening ports as the last. Without a dodger and cowl vents, opening ports take a higher priority.


Your boat, your choice.


Remember, the Nicro website has always had a very good discussion of boat ventilation, also available in the West Marine Advisor articles.


Happy boat hunting.

[whg1942]

For me on the Texas coast, a small Eva-dry Dehumidifier works great for keeping the humidity down.

[Lonewolf]

Originally Posted by Stu Jackson

My experiences have been a goodly mixture of many of the points made so far.


Our boat has eight opening ports plus one smaller one in the head; six in the saloon and V berth on the cabintop sides and two in the aft cabin opening to the cockpit footwell. We have two cowl vents (not truly dorades) that can be opened and closed; I leave them open all the time. There's a saloon hatch and a V berth hatch.



I have rarely opened the cabintop ports. The head port stays open unless it's raining or winter! Nice weather opens the V berth hatch and the saloon hatch. The aft cabin ports are left open in the summer, closed in winter. They are Beckson ports, with the head one being a Gray.


The dodger I find is indispensable for ventilation. Our two earlier boats didn't have them. Without a dodger the companionway must be closed up in questionable weather, whereas with a dodger, unless it's raining sideways from aft (!) it can be left open during the day.


Essentially we operate our saloon and V berth ports as if they were fixed, the rest are used.


The cowl vents provide the ventilation when it's cooler outside.


I would rank them as: dodger, cowl vents, selected opening ports, all opening ports as the last. Without a dodger and cowl vents, opening ports take a higher priority.


Your boat, your choice.


Remember, the Nicro website has always had a very good discussion of boat ventilation, also available in the West Marine Advisor articles.


Happy boat hunting.

Good point on the dodger. In fact a full enclosure with a Bimini is very high on my priority list because of this. Having a wet room outside for things to dry seems like a game changer. And the companionway ventilation as you mentioned. I'll check out that Nicro site, thanks