Cockpit Drain Hose - Awkward Size

[Chuncky]

The spigots on my cockpit drains are 42mm o/d. I therefore need a 42mm I/D hose to connect the spigot to the skin fitting. I've read a few threads about heating a 38mm pipe to fit. To install the pipe you need to climb into the sugar scoop via a small aperture and then lie across the scoop in a very small space. The prospect of wrestling with either boiling water or a heat gun to make a 38mm pipe fit the 42mm spigot in this space is not attractive, to say the least.

On a positive note I've noticed that 42mm is a standard size for engine cooling hoses, so I'm thinking that I'll go down the route of getting a very snazzy coloured 42mm silicon hose. As the duty is to carry ambient temperature rain/sea water at ambient pressure, I can't see a downside to this duty, apart from the cost of the hose.

What am I missing?

 

[CrikeyChris]

I’ve tried something similar (force a 38mm hose on to a hosetail a few mm larger) and I found it impossible - even with boiling water and heat guns. If these drains are exiting below the waterline you obviously want something very tough.

 

[andyc352]

The spigots on my cockpit drains are 42mm o/d. I therefore need a 42mm I/D hose to connect the spigot to the skin fitting. I've read a few threads about heating a 38mm pipe to fit. To install the pipe you need to climb into the sugar scoop via a small aperture and then lie across the scoop in a very small space. The prospect of wrestling with either boiling water or a heat gun to make a 38mm pipe fit the 42mm spigot in this space is not attractive, to say the least.

On a positive note I've noticed that 42mm is a standard size for engine cooling hoses, so I'm thinking that I'll go down the route of getting a very snazzy coloured 42mm silicon hose. As the duty is to carry ambient temperature rain/sea water at ambient pressure, I can't see a downside to this duty, apart from the cost of the hose.

What am I missing?

You’re not missing anything. I had similar problem with my cockpit drain hoses. I sourced silicon reducers online. They’re meant for use in car cooling systems so no problem coping with salt/fresh water at much lower temp. I was very impressed by the quality and ease of fitting.

 

[Motor_Sailor]

Yes, I used the silicone hose reducers from ASAP supplies. Then a plastic 38/38 straight connector into regular 11/2 inch drain hose/

Reducing Silicone Hose: 19mm to 51mm Silicone Reducers

 

[LittleSister]

I had a similar problem on a previous boat, in which the cockpit drains were formed by 38mm (actually 1 1/2" when the boat was built!) internal diameter PVC piping, the external diameter of which was too big to get the 38mm spiral reinforced hose I wanted to use onto.

After long searching without successfor an appropriate reducer, and contemplating numerous variations on affixing with epoxy or whatever a 38mm hose tail to the end of the over-sized pipe, none of which were entirely satisfactory, as a temporary measure I warmed a very short section of non-reinforced 38mm hose and forced it onto the pipe, the other end of which went on a double ended 38mm hose tail connector fitting. That 'temporary' bodge was still on the boat when I sold it.

 

[veshengro]

You could try expanding the hose to fit the 42 mm spigot before climbing into the Black hole of Calcutta. Cut the hose to the required length, soak the end in boiling water in the Galley and force a 42 mm tapered piece of wood into the end. One of those soft wood emergency bungs would do the trick. Let the hose go cold, repeat the process if necessary until it retains the preformed 42mm aperture. Smear the inside end of the hose with washing up liquid and it should slide onto the spigot once you have wriggled into the locker.

 

[BabaYaga]

The spigots on my cockpit drains are 42mm o/d. I therefore need a 42mm I/D hose to connect the spigot to the skin fitting.

42mm is indeed an odd size for a spigot or hose tail. Do you have this size also at the skin fitting?
Or is the 42mm referring to the o/d of a threaded part that goes through the cockpit floor/hull side (1 1/4")?

 

[jwilson]

I too have had struggles with water and diesel filler deck fittings which are quite a few mm too big for 38mm ID hose but too small for the next biggest hose size. And 38mm ID fits the tanks perfectly.

 

[Chuncky]

Thanks for the feedback folks. I'll source one of the silicon hoses and report back.

 

[Chuncky]

So I bought these 42mm I/D silicon hoses in a very fetching electric blue:

1 Meter Straight Reinforced Silicone Hose Coolant Water Heater Pipe | eBay

Pretty sturdy product. Fit was good on the 42mm spigot - slipped on nicely and held well with new jubilee clips. There also seem to be 42/38mm reducers of the same amterial available - maybe an option for other duties?