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Hanse 470, Rainwater problem

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Category: Hints and Tips
Forum Name: Older Models
Forum Description: Hints and Tips on Older Models
Printed Date: 12 April 2021 at 16:53
Software Version: Web Wiz Forums 12.01 -

Topic: Hanse 470, Rainwater problem
Posted By: kitesurfmore
Subject: Hanse 470, Rainwater problem
Date Posted: 28 February 2015 at 17:39
I just bought a second hand Hanse 470 (2010). Super happy with the boat. However I am in the process of ironing out some minor problems.

The boat looks like new, but has almost never been used by the previous owner (I bought the boat from the bank after his financial default).

What I have noticed is that there is a significant amount of rainwater in the bilge. I have asked an expert to look at where the water is coming from. It seems to get into the boat on the right side of the mast (not the mast itself), but it also leaks water into the port (aft) cabin.

I believe that I just want to replace all the sealings (silicone). The boat has been on the land for 2 years and was completely neglected. 

Are there any Hanse 470 owners on this forum, who have dealt with the same problems (Rainwater coming in). And how have you dealt with this problem?

Also I would like to add Hanse 470 owners to my buddy list to exchange ideas on this forum.

Best regards,

Happy Hanse 470 (2010), Owner

Posted By: Fendant
Date Posted: 01 March 2015 at 07:17
Hello Niels, you are describing one of the toughest problems on a boat to  solve. 
First: Are you sure that the fresh water in the bilge is really rainwater ? This being the case you have to trace the way it gets from the deck into the bilge. Deck Hardware is the most suspicious source of the trouble.  This you can trace by household tissue whih you attach all over the place in the aft cabin concerned, followed up by a serious freshwater shower of the whole deck aft from the mast. A helper inside the empty cabin will help you to identify the source of the trouble. Don`t use a pressure washer, just a simple hose with a nozzle. As you said, your leak is astern, which would exclude the often reported problem in the anchor locker.
Second: The source could also be your water heater, which has a safety valve. When you heat it up either through shore power or via the running engine the water in the hot circuit want to expand and lands finally in the bilge. Is your water heater in the same cabin? There are some threads here in the Forum proposing to lead a hose from the heater valve into a 1.5 lt PEZ bottle, installed easily accessible and emptied from time to time.
Third: The third source could be a leaking joint in your pressurized water System. It could be a too loose jubilee clip or a crack in the pipe/tank. Shourt run times of the water pressure pump with all taps closed would be the indicator or this. Again lots of houshold paper distributd under the joints would help to identify the suspect.
Iron rule:  Where you find the water in the bilge is never the location of the leak!
Happy Hunting!


Posted By: Wild
Date Posted: 01 March 2015 at 11:23
Hello Niels,
I can't speak for your 470 but we haved also issiues with some incoming rainwater in the past in our 545 2010.
When your boat has been for 2 year on the hard not used ,I think the source can't be the pressure watersystem our a leaking boilervalve , if the system as beiing in function all the time then after a while the batterys, tanks and boiler will be empty.
We get rainwater inside by the bad mounted Lewmar flush hatches ,the drains of this hatches are coming out on the sides of the boat with Vetus airvents with inside very fine SS filters, just take then out and be shure the drains are working well they block by sand etc.(we clean the channels every year 2 a 3 times) the water can not get out ,the
bad quality of the paint ( Lewmar not used a primer)on the allu frame become to corrode and finaly the water get inside by the frame ,the screws and between the deck and the inner shell ,find is way somewhere in the ceiling and get in the bilge at the end. After 2 years Lewmar sent us al the new hatches in warranty ,we removed the old one and closed the screw holes and the gap between the inner shell and deck with epoxy ,making the surface for the allu frame nice flat and fit the new very carefull with sikaflex ( fixing the screw 24 h later)Till now no more rainwater comes inside there.
We haved 2 leaks on the mast (Selden)section, one by the sailrail and after 4 year we have to change the mast coat.

Most of the water in the aftercabine was coming from the garage in our boat.
I try to sent some pict.

Wild and Wet

Posted By: Idelfix
Date Posted: 01 March 2015 at 15:02
See this post" rel="nofollow -

"Keep sailing in free wind"

Posted By: scott
Date Posted: 02 March 2015 at 02:34
Not sure it will help, but we've found and fixed two leaks on our 415. Now we've got a nice dry bilge, even in rainy Seattle.

1. Rainwater was collecting in the ceiling and eventually dripping down through the ceiling light right by the aft, port-side head. Our boat yard found the problem: a screw on the frame that surrounds the sliding hatch had been installed at an angle, and the rain water that is channeled there was finding its way down through the hole. Re-installing the screw and generous application of sealant in the area has fixed the problem.
2. The fresh water pump would kick in every 10 minutes or so, which was an easy clue to a fresh water leak. Luckily I found it in the first place I looked: the inlet connection to the hot water heater, where there was a slow drip whenever the system was pressurized. 

No problems since, knock wood!

Sailing Mer, Hanse 415, Hull #85

Posted By: kitesurfmore
Date Posted: 14 March 2015 at 11:22
Many many thanks to all of you, many suggestions. I am going to work on these and once I have made progress I will report back.

One other item I have noted on my 470:

Around the base of the stanchions are polyester rings. Not flexible. Three of them have started to crack.

I am thinking of a solution for this. But this could also cause rainwater to come in?

Happy Hanse 470 (2010), Owner

Posted By: Yeoman
Date Posted: 14 March 2015 at 13:43
It is also worth checking where the side deck drain holes go to.  On some versions they simple drain down the side of the hull on others there is a pipe to a skin fitting in the hull.
Kind regards

Inspiration Marine Group LTD - UK Importer for Hanse Yachts. Helping owner’s to get the best from their boats.

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