More questions from a catamaran cruiser wannabe

[TacomaSailor]

My wife and I have been sailing larger monohulls for over 40 years. We have done quite a bit of cruising from the North end of Vancouver Island to Acapulco in our Caliber 40 during the last 20 years. We have lived aboard off and on during the last 14 years.

We are now seriously considering a 40’ – 50’ catamaran as our next live aboard home and long distance cruiser. We will spend 90% of the next 5-years cruising in the Northern Hemisphere tropics. We will live at anchor 320 or more days a year.

We’ve lived aboard in the Western Mexico tropics (including three summers in the Sea of Cortez) on three different boats. Each of those boats had a lot, really a lot!, of opening hatches, ports, doors. The cross-flow ventilation was great and the boat interiors stayed pleasant under the brightest tropical sun.

Two of the 47’ – 52’ cats we have looked at had very limited opening side and front windows and just one or two overhead hatches. They did have large aft facing openings to the aft deck. But, at the dock in San Diego with 10 – 12 knots of wind blowing – both interiors seemed stuffy and warm even with all the hatches open.

Additionally, all the cats have big flat cabin tops that absorb a lot of solar energy.

Questions

1) Do big cats with few side and front opening windows/ports get enough airflow to stay cool in the hot tropical sun?

2) Is it practical to put a boom tent over the cabin top on a big cat?

3) How important are the side and front openings in a catamaran living on the hook in the tropics?

[tomfl]

Originally Posted by TacomaSailor

SNIP

Two of the 47’ – 52’ cats we have looked at had very limited opening side and front windows and just one or two overhead hatches. They did have large aft facing openings to the aft deck. But, at the dock in San Diego with 10 – 12 knots of wind blowing – both interiors seemed stuffy and warm even with all the hatches open.

Additionally, all the cats have big flat cabin tops that absorb a lot of solar energy.

Questions

1) Do big cats with few side and front opening windows/ports get enough airflow to stay cool in the hot tropical sun?

2) Is it practical to put a boom tent over the cabin top on a big cat?

3) How important are the side and front openings in a catamaran living on the hook in the tropics?

Airflow at the dock can be much different than airflow on the hook, or ball. Some big cats get enough airflow, some don't. You might ask about specific ones.

I have seen lots of boom tents and other shading devices and they can be designed to work very well.

If you are on the hook front openings are much more important than side openings.

[SvLetitgo]

Been living in the tropics for 2 years now. Our 380 lagoon never got hot or stuffy. We tried the air scoop made no difference idem for the tent even reducing the flow of air we found.

The side hatches don't bring the air flow the deck and front windows does the work perfectly.

At anchor you will away be good in Marina that an other story.

[tomfl]

Originally Posted by SvLetitgo

Been living in the tropics for 2 years now. Our 380 lagoon never got hot or stuffy. We tried the air scoop made no difference idem for the tent even reducing the flow of air we found.

The side hatches don't bring the air flow the deck and front windows does the work perfectly.

At anchor you will away be good in Marina that an other story.

My experience with an air scoop has been good, makes a tiny breeze much more obvious.

I also have not only what would pass for a boom tent, but a canvas shade over the forward bridge deck/tramp and forward hulls.

There is no question that airflow is much better off the dock.

[chris in SG]

The importance of side openings (opening ports) seems to be under-estimated. They allow air to EXIT and thereby allow air to flow through cabins rather than reaching a 'dead-end'. A light breeze arriving through a main forward opening port can be completely wasted if there is no through-flow of air.

[tomfl]

Originally Posted by chris in SG

The importance of side openings (opening ports) seems to be under-estimated. They allow air to EXIT and thereby allow air to flow through cabins rather than reaching a 'dead-end'. A light breeze arriving through a main forward opening port can be completely wasted if there is no through-flow of air.

I have never seen a boat that did not have a companion way the air could exit out of. I know some aft cockpit boats may need to have the air come in the top and exit forward through the companion way.

[Factor]

And of course on your boat tom there are hatches at the rear of each hull which provide a good "exhaust" port

[chris in SG]

Originally Posted by tomfl

I have never seen a boat that did not have a companion way the air could exit out of. I know some aft cockpit boats may need to have the air come in the top and exit forward through the companion way.

Most aft cabins are a ventilation 'dead-end' unless side-opening ports are available and open. The same would be true of forward cabins unless all cabin doors are open to allow a through flow of air to the companionway.

Don't really see this as contentious, it's obvious..

[svfraidknot]

i live part time on my cat in the bay of panama single most important issue for me was anchorage versus mooring ,, the bottom here is really rotten and you need at least 150 foot of chain. when you move it takes n extra hour to clean the chain as if you put in the locker without clean in it good with klorox even it will stink you out of your boat in a few days . a mooring here is 250 a month and you pay 5 bucks each trip to and from your boat. you can leave a dingy on the dock for day trips but if you leave it a few days or even over night things happen .. panama is great as you can pretty much find anything you need to live here and repair your boat. shipment from the states is easy and fairly cheap . toboga island is a couiple of hours away for a day trip or overnight ,, the perlas islands 8 hours or so and you could spend the next 2 years exploring them ,, mine is a "solaris 42" the most comfortable boat i have ever stayed on ,, may have to sell her or take on a " partner " in the near future though as my finances have taken a turn for the worse ,, sv fraid knot

[svfraidknot]

sorry i got carried away ,, i have a froward berth with two hatches overhead " facing forward" and the small "computer" fans . it has been all i have needed to stay cool ,, rear berths have larger hatches facing rear and the scoops help a lot , they are not near as cool and i have larger fans to help circulation ,, panama is in the high 80s during the day low 80s at night but the wind blows one direction or the other 90 % of the time. seems cooler in the islands once you get away from the main land as well

[RichinBoca]

Not sure what your budget is but take a look at the Antares 44i. The boat is extremely well designed and built with sensitivity to air flow. If nothing else take a look at the videos and see the discussion on ventilation for the live aboard it will give you some additional perspective. LiveAntares.com


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[shawndear]

Hi

Questions

1) Do big cats with few side and front opening windows/ports get enough airflow to stay cool in the hot tropical sun?

I am the owner operator of a Fountaine Pajot Bahia 46' charter catamaran running through the Grenadines and don't have any issues with air flow during all but the stillest of the hurricane season months. If we have 10-15knots of wind, all the cabins and saloon is comfortable. Each double forward cabin has a nice 500mm ish forward facing hatch and a side hatch. unless there is a strong beam current, very little comes through the side hatch but more than enough comes through the top hatch. The saloon also has 2 of the large hatch which ventilates the saloon well although whilst cooking roasts for guests it can get a bit warm for the cook.



2) Is it practical to put a boom tent over the cabin top on a big cat?

You could but I don't think it will make much if any difference. The coach roof is white so highly reflective and never feels warmer than the surroundings/ In addition, it is a decent thickness so would guess it is reasonably insulated.

3) How important are the side and front openings in a catamaran living on the hook in the tropics?[/QUOTE]

Kind of answered above. Not much use unless you are in a strong beam current but then the opposite side wont get any breeze. A wind scoop could help and then each cabin has a fan for these occasion and when it rains.


Hope this helps.

Shawn from SY Imagination.

[tomfl]

Originally Posted by Factor

And of course on your boat tom there are hatches at the rear of each hull which provide a good "exhaust" port

While that is true the size of the companion way is much larger than the hatches at the rear of each hull. Not to put too fine a point on it but Seawinds are some of the best designed boats I have ever seen in terms of livability. I would also point out I have a composting head with a 24/7 fan which results in negative pressure in the port hull which is where the bunk is.

I still go around the harbor and take pix of what I consider interesting boats. Most of the cats I see (which if the truth be known are condomarans) look like a brick wall from the stern. On the other hand Seawinds look open from the stern and offer not only visibility but ventilation as well.