How Are the Tropics "Hard on Boats"?

[SomeGuyInaShirt]

So I'm almost in Mexico on the Pacific coast and I'm headed into the Sea of Cortez planning my next move.

I was thinking of leaving the boat ashore (in Mexico) for a year to 18 months to work and possibly do a few months of bicycle touring in Europe but I remember all the stern warnings about how the tropical sun is "hard on boats" with no further explanation as to how.

What will I come back to after 12-18 months? Should I avoid doing my brightwork and repainting my nonskid as planned? I bought some light sand coloured nonskid in the spring but had to launch before I had time to apply it to the deck. If I paint it before I leave for work will it be trashed when I return? Is the integrity of my fiberglass going to be affected?

[HeywoodJ]

It starts with UV for anything exterior. Just as UV causes the bulk of human sunburn, it does the same thing to everything plastic on your boat (fiberglass hull, synthetic rope, paint - all of these are plastic of some kind). The images below give you an idea of average UV intensity at the start of summer in each hemisphere. As you can see, the tropics get hit hard all the time.

Then there's humidity, and temperature swings, neither of which are kind to a closed up boat interior. Desert air in the Sea of Cortez may be better, but then the temperatures become more extreme too, expand-contract-expand-contract.

These happen anywhere, but the tropics take them to extremes. Lots of people store their boats in the tropics, you just have to prep properly, and to expect some work when you get back to them.

[SomeGuyInaShirt]

Originally Posted by HeywoodJ

It starts with UV for anything exterior. Just as UV causes the bulk of human sunburn, it does the same thing to everything plastic on your boat (fiberglass hull, synthetic rope, paint - all of these are plastic of some kind). The images below give you an idea of average UV intensity at the start of summer in each hemisphere. As you can see, the tropics get hit hard all the time.

Then there's humidity, and temperature swings, neither of which are kind to a closed up boat interior. Desert air in the Sea of Cortez may be better, but then the temperatures become more extreme too, expand-contract-expand-contract.

These happen anywhere, but the tropics take them to extremes. Lots of people store their boats in the tropics, you just have to prep properly, and to expect some work when you get back to them.

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What sort of work specifically?

[Stingo]

Originally Posted by SomeGuyInaShirt

What sort of work specifically?

As an example, if your boat is on the hard in a place like Chaggaramus, Trinidad, which is downwind of the oil refineries, within a few weeks, your boat will turn black. It takes a lot more than a pressure wash to get the oily grim off the boat and then to get all the running rigging cleaned.

[Don C L]

We aren't in the tropics here but under the high UV and repeated cycles of hot and cold, everything degrades it seems. But specifically, keep your wood and sails covered for starters. SOC can be brutal. Around here we get those conditions at times in the summer. These reflective tarps (reflective side out) are worth their weight in gold to me at times, though they aren't aesthetically pleasing or popular with neighbors!

[roryboy]

Bugs. Cockroaches (cockroaches. Call them legion: for they are many) will happily make a home of your unattended vessel.

[SomeGuyInaShirt]

Originally Posted by Stingo

As an example, if your boat is on the hard in a place like Chaggaramus, Trinidad, which is downwind of the oil refineries, within a few weeks, your boat will turn black. It takes a lot more than a pressure wash to get the oily grim off the boat and then to get all the running rigging cleaned.

That doesn't sound like much fun. I guess it cuts down on metal corrosion at least, haha.

I think I spent two full days acid washing my boat and another two compounding and polishing it after 1.5 years ashore in British Columbia though so it doesn't sound too different from the usual.

Thanks for the reply: )

[SomeGuyInaShirt]

Originally Posted by roryboy

Bugs. Cockroaches (cockroaches. Call them legion: for they are many) will happily make a home of your unattended vessel.

How do you get rid of them? I have an ozone generator but I don't think it'll work for roaches. I heard they can live without air for a long time.

[SomeGuyInaShirt]

Originally Posted by Don C L

We aren't in the tropics here but under the high UV and repeated cycles of hot and cold, everything degrades it seems. But specifically, keep your wood and sails covered for starters. SOC can be brutal. Around here we get those conditions at times in the summer. These reflective tarps (reflective side out) are worth their weight in gold to me at times, though they aren't aesthetically pleasing or popular with neighbors!

Great idea with the tarps. I'll try to find some in Mexico.

Did you get fog in the islands? I went from San Luis Obispo Bay to Point Conception yesterday in half mile visibility that has only just now cleared up. Quite the experience. I sure am thankful for GPS and AIS.

[Don C L]

Originally Posted by SomeGuyInaShirt

Great idea with the tarps. I'll try to find some in Mexico.

Did you get fog in the islands? I went from San Luis Obispo Bay to Point Conception yesterday in half mile visibility that has only just now cleared up. Quite the experience. I sure am thankful for GPS and AIS.

Oh sure we get fog! Half a mile visibility is not too bad. But the back side of the islands occasionally have a climate a lot like Baja!
If you are still out there I guess you'll be feeling the flip side with the wind coming down the coast tomorrow.

[JPA Cate]

What you REALLY need to consider is that the tropics is where hurricanes happen. So don't bother to cover your sails. Take them off, bag them, and store them below decks. Ditto all weather cloths. Good quality chafe guards for where the dock lines go around the cleats; or, if on the hard, then tie down lines. Doubled. Tenting the boat can protect it from dirt, but it adds windage, and imo, the windage is the greater problem, because if the boats are stacked on the hard, high windage can lead to domino events, where they all go over; and if it isn't tied up properly and properly fendered, the wind strengths will cause the boats to leap up on the docks. You should, imo, look at recent hurricane damage to marinas pictures to get an understanding of how much danger your plan would cause your boat. Don't take my word for it. You don't know me or my experience.

Fwiw, the trend right now is that hurricanes may be fewer, but are likely to be more intense, and windage and chafe are two major hazards to address.

Sailboats tend to go downhill when you are not living on them, ready to spend a day or two keeping things up. Engines need to be run to stay happy. Things like coolant impellers will fatigue from sitting in one position for a long time--plan to replace them when you return to the boat. When they break, the bits that come off can get into the coolant passages in the engines, causing overheating.

If you can find the location for it, leave the boat in the San Francisco Bay area, for your European travel, especially if you think that might run to 18 months. You'll still be best off to leave it with the sails stowed below and the lines doubled up. The bay area gets some winter storms, but is not subject to hurricane force winds often.

I wouldn't expect damage to deck non-skid paint, but there are lots of ways of catching filth: brake dust from nearby highways; being in flight paths where fuel is used excessively for take offs and landings, or is dumped in case of emergency; being downtide from dumps can lead to various corrosive effluents in rain; and beware of stray electric currents in marinas which can eat saildrive legs, an of course, zincs.

If you haven't bought the boat yet, maybe go to Europe first. If you really have the boat now, then maybe follow your sailing plans first and do Europe later on. Set yourself up to succeed.

Ann

[Benz]

People leave boats in San Carlos, up in the Sea of Cortez, for extended periods. The weather is dry, which is key. There will not be many cockroaches (it's the desert, and cockroaches need food. Don't leave any food sources aboard, and especially don't leave or bring aboard cardboard).
Just do what you see others doing: mouse out your halyards, store all canvas and cloth below, expect your varnish to be trashed. Your fiberglass will be fine. I'd paint AFTER I returned, so it's all pretty.

[Ryban]

Temperature swings in the tropics are actually generally less severe than higher latitudes. Places like the desert regions of Baja experience far greater differences in day/night-time temperatures, simply because the air is a lot drier, and the sky is generally clearer, which translates to colder nights, and hotter days.

Though UV is an issue as noted above, compared to the Baja region, the biggest difference will be the humidity and rainfall. It doesn't take very long for a closed-up unattended boat in the tropics to be covered in mold.

[Fore and Aft]

SomeGuyInAShirt another issue that can happen anywhere is water intrusion. I have had a couple of clients come back to their boats after long term storage to find water above the floorboards. A keel stepped mast, failed bilge pump and a lot of rain contributed to one disaster. Another disaster that didn't involve water over the floorboards was a porthole left slightly open above the bed. When I went onboard the mattress was soaked, full of mould and the all the surrounding timber panelling badly damaged.
Blocked cockpit drains and a water intrusion through cockpit lockers is another way water can get inside.
Cheers

[Marathon1150]

We had our boat in La Paz for 10 years and then Tahiti for 3. The problems are/were slightly different in each location and may depend on how frequently you or someone else can visit the boat.

In La Paz, the sun is brutal in the summer and only slightly less brutal the rest of the year. As others have said, UV degradation of cloth (even Sunbrella), wood and plastic is a challenge. 303 protectant helps with the plastic and Cetol lasts longer than varnish, at least in my experience. SEMCO for teak decking helps a lot.

La Paz is dry except in the summer so the combination of heat and humidity July, August, September is very nasty inside the boat. We kept our boat in the water year round but many friends put their boats on the hard but removed all tin cans given that temperatures inside the boat can lead to exploding food cans.

Cockroaches can be minimized with the various boric acid products available in most stores. Putting it in places that you won't disturb but cockroaches like (dark and damp like under the galley sink) will minimize if not totally prevent infestations. We had one at the same time that everybody else on the dock did but got rid of it with Raid anti-cockroach spray followed by the boric acid treatment. Some people had their boats fumigated.

La Paz is surrounded by the ocean and desert. Our boat is now back in Vancouver and the rain continues to wash very fine dust out of the canvas and the sails.

Tahiti was worse. At least in part because the boat was there during the pandemic and we could not get to it. We had someone open it up once every two weeks, start the engine, pump the head and check the bilge. Nonetheless, anything made out of rubber or plastic inside the boat was no longer useful or needed a lot of work to get it working again. Cans rusted and leaked, plastic bottles fractured and lost their contents (our boat watcher wondered what the weird green liquid in the bilge was - I discovered that it was coolant that had leaked from a cracked plastic jug. Fortunately the jug of motor oil next to it, developed its crack at the top and not at the bottom like the coolant). You can read the whole sad story here:

https://currents.bluewatercruising.o...ting-horizons/

Hurricanes are mentioned above in this thread and they are a real concern in the Sea of Cortez. Our boat suffered minor damage from Hurricane Odile in 2014 but three sailors in La Paz lost their lives, many boats were sunk, went aground or blew over on the hard. We were not there but we were very lucky that friends kept an eye on our boat and replaced dock lines as they chafed through. They said it was terrifying.

Nonetheless, the Sea of Cortez is amazing, Mexico is great and we loved being there on our boat.