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air vents

colin loach

By colin loach
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AlanH Proficient

AlanH

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Hi all. I want to take my cruiser stern boat down the themes but there are two air vents on the back each side.I Don't want any water to go into the engine compartment so

could I block the vents in for 2 hours

They are to allow the engine to take in fresh air. If you block them you could well affect the performance. Woiuld be OK if you lifted a deck board to allow air in for the duration.

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alan_fincher Veteran II

alan_fincher

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They are to allow the engine to take in fresh air. If you block them you could well affect the performance. Woiuld be OK if you lifted a deck board to allow air in for the duration.

Lets be careful here....

 

That's probably fine if it's a water cooled engine, and these are just permitting air into the engine compartment.

 

But if it's an air cooled engine, (something like the SR or ST series, for example), then one of these will be connected to the engine by steel or metal trunking, and is how the engine gets rid of it's hot air, rather than just recirculating it.

 

Block one of those, and the engine will rapidly overheat.

 

(Sorry if that's a bit obvious, but just in case!....)

 

Has anyone exsperienced the themes and had water coming in.

Which bit are you planning to do?

 

Brentford to Teddington (or Vice Versa), or are you goin'g on the bit through London to Limehouse?

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blackrose Veteran II

blackrose

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How high above the waterline are the vents? Most including mine are about 18" above the waterline, but in my opinion is not a great design feature. For watercooled engines the vents are there primarily for the engine's air intake and perhaps to facilitate alternator cooling, so there's actually no reason for them to be anywhere near the waterline and some builders are now putting the vents higher up on the side of the control pedestal. (Not sure if that's the correct term - the upright steel box on many modern boats with the morse contol and gauges on top.)

 

Most of the waves on the tidal Thames tend to hit the bow or come across the beam when you can't turn into them because a bridge is approaching for example, but if you're worried about your vents being too low for that trip perhaps you could use some sort of ducting and waterproof tape to raise the intake.

 

Edit: As Alan says above - if you're just doing Teddington to Brentford don't even worry about it.

Edited by blackrose
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blackrose Veteran II

blackrose

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its a Liverpool boat with a Isuzu 45 engine water cooled the vents are about 18in off the water line. they are 10in x 6in. I want to go down to limehouse or a bit further, may be I could design some sort of water tight vent . any idea's

 

Mine's a LB too and I had no problems going down to Limehouse - if one or two waves do splash against the vents only a few cupfuls of water would get in so it's not going sink the boat. Don't block the vents and don't leave the deckboards off! Keep your bow doors shut and you'll be fine.

Edited by blackrose
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colin loach Collaborator

colin loach

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Mine's a LB too and I had no problems going down to Limehouse - if one or two waves do splash against the vents only a few cupfuls of water would get in so it's not going sink the boat. Don't block the vents and don't leave the deckboards off! Keep your bow doors shut and you'll be fine.

thats just what i wanted to hear, thanks very much i will let you know how i get on. Colin

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stuart Experienced

stuart

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I'd just make sure that theres nothing blocking the vents (battery boxes etc.) and also make sure your bilge pump is working properly (perhaps fit another one?) - any water that does get in will be pumped back out again.

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blackrose Veteran II

blackrose

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I've done that trip a couple of times - once without any accompanying boats. In retrospect that probably wasn't such a great idea. The last thing you want to do is have to deploy your anchor in the event of engine trouble or a fouled prop - you don't know if/when it's going to stop you or exactly what will happen once you drop it. There are so many bridges on that stretch you could easily smash into one.

 

In future I think I'd always go with another boat. If one of you has a problem, they can always throw a rope to the other for a tow. If the lead boat has VHF then the other doesn't have to, but don't forget to exchange mobile numbers before you set out.

Edited by blackrose
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colin loach Collaborator

colin loach

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I've done that trip a couple of times - once without any accompanying boats. In retrospect that probably wasn't such a great idea. The last thing you want to do is have to deploy your anchor in the event of engine trouble or a fouled prop - you don't know if/when it's going to stop you or exactly what will happen once you drop it. There are so many bridges on that stretch you could easily smash into one.

 

In future I think I'd always go with another boat. If one of you has a problem, they can always throw a rope to the other for a tow. If the lead boat has VHF then the other doesn't have to, but don't forget to exchange mobile numbers before you set out.

I will take your advice and go with someone else. I haven’t got vhf so hope a Mobil will do. I wanted to take in all the sites, so didn’t want to rush. I was told you can get in at limehouse even at low tide, do you think my 45 engine will be ok against the tide.

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Canalwatcher Community Regular

Canalwatcher

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I will take your advice and go with someone else. I haven’t got vhf so hope a Mobil will do. I wanted to take in all the sites, so didn’t want to rush. I was told you can get in at limehouse even at low tide, do you think my 45 engine will be ok against the tide.

Colin

 

You might find the following link helpful for planning your trip

 

http://www.pla.co.uk/pdfs/IWA_Thames_Tideway_Guide.pdf

 

The bit about VHF in this guide is out of date see page 8 of

 

http://www.pla.co.uk/pdfs/maritime/General...nters_copy1.pdf

 

I think I have read that it will not be possible to always get in at Limehouse - you might have an an uncomfortable wait moored to a buoy - its easier to do the trip from Limehouse to Teddington

 

Not that I'm much of an expert having only done Teddington to Brentford a couple of times

 

I wouldn't think there are any worries about the vents though

 

 

 

Mick

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sbillis Collaborator

sbillis

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Hi all. I want to take my cruiser stern boat down the themes but there are two air vents on the back each side.I Don't want any water to go into the engine compartment so

could I block the vents in for 2 hours

 

When we took Bulrush on the tidal Thames a few years ago the waves come over the vents, even onto the platform where I stand. I thought that the engine compartment would get flooded. When I checked it at Teddington it was bone dry. Somehow the water didnt go in.

 

Simon

nb Bulrush

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colin loach Collaborator

colin loach

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Colin

 

You might find the following link helpful for planning your trip

 

http://www.pla.co.uk/pdfs/IWA_Thames_Tideway_Guide.pdf

 

The bit about VHF in this guide is out of date see page 8 of

 

http://www.pla.co.uk/pdfs/maritime/General...nters_copy1.pdf

 

I think I have read that it will not be possible to always get in at Limehouse - you might have an an uncomfortable wait moored to a buoy - its easier to do the trip from Limehouse to Teddington

 

Not that I'm much of an expert having only done Teddington to Brentford a couple of times

 

I wouldn't think there are any worries about the vents though

 

Thanks for that link, it made interesting reading( scary)

 

Mick

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WJM Veteran

WJM

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Liverpool boat here too. Done the Limehouse trip lots of times with no problems, even on really rough days. As already said, the waves tend to hit the front of the boat. Even if the occasional splash gets in, your bilge pump will chuck it back out.

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