Who in the right mind would fit these vents!!!

[Chas78]

Hi All,

After discovering many leaks on my boat firstly from the windows then above the windows so i decided to investigate the roof vents this is what i found  who in the right mind would fit these and more importantly cover them with roof lining and insulation when they are there for a reason and they were leaking very badly as can be seen after the many drill/screw holes left unsealed the mind boggles 

[RLWP]

Very popular at one time, they don't catch on ropes and let in a bit of light

Richard

[Guest]

I hate roof vents of any sort. Would never fit them on a future boat (not that there is likely to be a future boat!)

[Chas78]

Think i will go for mushroom vents next 

[Alan de Enfield]

54 minutes ago, Chas78 said:

Hi All,

After discovering many leaks on my boat firstly from the windows then above the windows so i decided to investigate the roof vents this is what i found  who in the right mind would fit these and more importantly cover them with roof lining and insulation when they are there for a reason and they were leaking very badly as can be seen after the many drill/screw holes left unsealed the mind boggles 

I guess it was the installer that was at fault, rather than the vent design.

These are the 'standard' vents for sea-going boats so if properly installed should not pose a problem on a muddy ditch.

There are 3 fitted ( 2 on the front deck / cabin roof, and one on the saloon roof) on our Category B cruiser

[Detling]

More relevant what idiot covered them up with insulation. If they had arranged alternative ventilation they should have removed and sealed the roof properly, if no other ventilation I hope they survived.

[system 4-50]

If you fit them as per instructions you end up with millions of screw holes. I fitted them differently and ended up with only 4 per fitting and they are all watertight but can get slight condensation in extreme cases.  I much prefer them to mushrooms but something properly designed for narrowboats rather than plastic boats would be better.

[Chas78]

7 minutes ago, Detling said:

More relevant what idiot covered them up with insulation. If they had arranged alternative ventilation they should have removed and sealed the roof properly, if no other ventilation I hope they survived.

The previous owner covered two vents one of which i will also be removing if it ever stops raining yes they survived 

[David Mack]

5 hours ago, system 4-50 said:

If you fit them as per instructions you end up with millions of screw holes. I fitted them differently and ended up with only 4 per fitting and they are all watertight but can get slight condensation in extreme cases.  I much prefer them to mushrooms but something properly designed for narrowboats rather than plastic boats would be better.

Belfast has them and they are pop riveted to the roof! And one is leaking and all of them have gunk under the clear bit. So I am going to have to drill out the rivets to clean/seal, and then decide whether to rerivet or tap threads in the roof.

[system 4-50]

These are the notes I made for myself. 

 

Method of Fixing Ventairs (for centrally sited) using only 4 roof fixing holes.

The parts involved are:

1. The SS UFO plate
2. The top plate
3. The bottom plate
4. 12mm M5 Bolts (not screws)
5. Yellow rawlplugs
6. LSX

 

• Prepare the fixture as follows: 
• Note some fit together well without glue.
• Glue 3 yellow plastic rawlplugs into the top plate so they project below & are flush(ish) above.
• FIT THE MOZZY NET!
• Glue the projections and the bottom plate post bases and glue the top plate to the bottom plate.
• ENSURE THE TWO PARTS ARE SAT TOGETHER CORRECTLY. THIS IS HARD!
• When set, trim off any exposed rawlplug.
• Fill the screwholes in the fixture with sealant
• This avoids the need to use screws into the roof for the fixture. 
• It is not possible to screw or bolt the two plates together.
•  
• Ensure the rubber sealing ring is seated correctly.
•  
• Fitting:
• Locate approximate area.
• Locate neighbouring roof ribs
• Ensure not close to hand rail  or other top sides features on roof
• Ensure no cables
• Drill small pilot hole from underneath
• Use this hole as bow/stern position guide only, drill new pilot midway between port & starboard (if required!)
• Drill starting hole must be the same size as the following hole saw (8mm???)
• Cut with 98mm hole saw with dab of trefolex (beware silicones). Faster works better, with cooling stops.
• No. The holesaw overloads the DeWalt drill. Use Starrett jigsaw blades, is easier.
• The Victron cannot cope - use the generator
• Paint the rim with Hammerite
• Fit the fixture in position
• Place the UFO in position:
•     Ensure drain holes are in the lowest position
•     Avoid screw holes in the lowest position
•     Mark the UFO plate with a marker pen to indicate the bow-most point 
•     Ensure the fixture underneath is correctly seated
• Drill out one screw hole in the UFO and roof beneath to 4mm. This and the next hole should be in the long axis of the boat to minimise at this stage bending of the UFO plate.
• Tap out the hole to 5mm
• Drill out the UFO plate only hole to 5.5mm
• Refit & bolt this hole. Note - use 12mm M5 bolts not screws.
• Repeat for the second hole.
• The last two holes are harder because of the curvature of the roof but the process is the same.
• When all bolts fit easily then remove them one at a time and LSX the hole and the stem, rebolt & wipe clean.

Addendum: Insulate any exposed steel inside the cabin around the projecting ventair as this will collect condensation at a great rate, but do it in such a way that the Ventair can be removed as necessary to clear the drainage channels. Difficult.

 

[Movin' on]

15 hours ago, Alan de Enfield said:

I guess it was the installer that was at fault, rather than the vent design.

These are the 'standard' vents for sea-going boats so if properly installed should not pose a problem on a muddy ditch.

There are 3 fitted ( 2 on the front deck / cabin roof, and one on the saloon roof) on our Category B cruiser

NICE BOAT

[Kendorr]

Me.

Look after and maintain them, they are good. Generally called UFO vents.

Kevin

[dccruiser]

I have them on my narrowboat and never had any issues with them ... and on another plus note over mushrooms aside from not snagging ropes they dont get nicked to be weighed in or need polishing or painting  

 

Rick

[mrsmelly]

1 hour ago, dccruiser said:

I have them on my narrowboat and never had any issues with them ... and on another plus note over mushrooms aside from not snagging ropes they dont get nicked to be weighed in or need polishing or painting  

 

Rick

Mine are painted nice red gloss.......lubbly jubbly........do you mean some people polish em 

[peterboat]

Had them on my first boat it was an ex share boat the vents worked fine I removed them when I painted the roof without issues [stainless screws] and refitted them as easy peasy As others have said ropes dont get caught in them, I will fit them to the bath tub when fitting out

Edited January 16, 2018 by peterboat

[adrianh]

I used to have them until the boat safety deemed that they had insufficient air flow to match my appliances some 20 years after the boat was built!

Had to change them all to mushrooms which do drip condensation occasionally

[Guest]

Our first hire boat had roof vents just like these. As pointed out above the lines never caught on them, unlike the mushroom vents on our own boat.

[dccruiser]

On 1/16/2018 at 17:26, peterboat said:

Had them on my first boat it was an ex share boat the vents worked fine I removed them when I painted the roof without issues [stainless screws] and refitted them as easy peasy As others have said ropes dont get caught in them, I will fit them to the bath tub when fitting out

Painting my boat next month so hoping i have the same experience removing and refitting them  ... another thing about them is apart from being less obtrusive and easy to trip over they dont affect where i can put my solar panels.

Rick

[Tony Brooks]

I don't understand where 14 fixings come form. 4 for the cover, 3 for the plastic insert. The remaining holes in the base of the plastic are, I believe, drain holes so water can drain away instead of overflowing into the boat.

These vents have two free air flow dimensions, with and without the insect guard. maybe Adrianh could have just removed the insect guard. I have also heard of people packing the fixing between the two plastic parts to get more free air flow. Not sure how they deal with the cover though, maybe they dish it.

[John Edney]

Hello Everyone. I have a few of these vents on my boat. When I first got my boat some of them leaked, but not any more. The secret is that if you look carefully at the silver trim there slim raised sections on them. These are drain holes that allow any water inside the vent to escape. The plastic trim sits about an inch above the height of the roof, with a gap above for the air to get in. If you allow moss and debris to block the drain holes on the silver trim the water will build up till it drips over the top of the plastic trim. I find a small very thin screw driver every now and then does the trick.

[dor]

J had one of these on my previous boat.  It started leaking quite a bit and I took the cover off.  The plastic inner had degraded and cracked.  I tried to get a replacement from a local chandlery who told me they didn't stock them any more as they were not compliant with the BSC (this in about 2003 when I think the ventilation requirements were more strict - presumably for new installations only).

I replaced it with a mushroom vent, but presumably when ventilation became advisory, any problems with the UFO vents was put aside.