Dorade boxes and vents questions

[Boo2]

I am lusting after dorade vents to improve Sunrunner's not-very-good ventilation and have been looking around. There seem to be a few types of reasonably priced ABS plastic cowls and boxes like the Plastimo ones available here for example.

My concern is that ABS is not the strongest of materials and if they get stomped on they'll break. This guy made his own dorade boxes to the Plastimo pattern but out of teak. They look great but I do not have the skills to do that. Does anyone know where I could buy grp versions of the Plastimo dorade boxes at a reasonable price ? C-Quip do one but it's nearly £200 with VAT

C-Quip also do nice stainless steel cowls like this type and this low profile type but they are also rather dear to say the least. Vetus also do cowls and dorade boxes at similarly prices.

Are the low profile cowls much worse in airflow terms than the normal ones ? Also, are the stainless ones adequately strong to withstand someone tromping on them by mistake ?

Any advice from experience welcome,

Boo2

 

[billcowan]

The Vetus are rubbish, made from PVC. 3 years in the med reduced mine to sticky brown turds. The winch handle pockets went the same way.

Your wrong about ABS. its what good telephones and things are made of. Good UV performance and good impact strength

But I see that with the Plastimo the cowl is also PVC only the box is ABS

 

[Ex-SolentBoy]

The Plastimo ones are quite soft and flexible, but the top section screws into the bottom. You can rotate them to point in the required direction, but the thread is not that long and easy to strip. We have lost a couple over the years.

Yes, treading on them is an issue, but for us it was much more worrying that we would catch a sheet on them. Depends on your boat layout, but we opted for stainless guard bars. Solves both the treading on and sheet problem in one go.

 

[Fr J Hackett]

When you eventually fit them drill a small hole in the side of the cowl and another in the box and use a shortish length of line to secure the cowl to the box that way when you do kick one or the sheet pulls one out of the box you don't loose it.

 

[PlankWalker]

Also when you fit them, make sure the hole in the deck doesn't become the source of water ingress to any balsa or foam if you have it.
Rake out core material and fill with epoxy.

Plank

 

[Bobobolinsky]

When you eventually fit them drill a small hole in the side of the cowl and another in the box and use a shortish length of line to secure the cowl to the box that way when you do kick one or the sheet pulls one out of the box you don't loose it.

Top tip, I recovered one of mine from the side of the dual carriageway, following a transport.
Come on lad a few feet of 150mm x 20mm timber, and a router. Even the cowl and ring is 20 odd squid. Easy to make and so much more satisfying to see that traditionl hardwood brightwork

 

[Burnham Bob]

Don't bother with the Dorade box. We have a Plastimo cowl that screws direct on to a deck fitting, and was supplied with a threaded blanking cover for when you are sailing. Using that means there is virtually nothing for genoa sheets to catch on. But it is essential to tie it on as suggested above We've lost two through forgetting to put the baklnking cover on and over enthusiastic crew pulling the sheets and sending the cowl overboard. And Plastimo seem to change the screw thread every twenty minutes so the new cowl you buy won't screw on and you need to replace the deck fitting too.

My boat already had a deck hole cut so no problem there, but I must admit that when replacing the deck fitting I have over siliconed like mad, wiping it round the hole where it goes through the deck (you can see the exposed balsa sandwich) and putting plenty of gunk underneath the fitting. Luckily the screw holes are always in the same place so new holes aren't needed but again I squirt as much silicon as possible down the holes before putting in the screws.

The ventilation is wonderful and we've never had rain come in although driving rain direct into the cowl might do that.