# Hallberg Rassy Rasmus Fuel Tank Leakage



## tsuidc (Mar 2, 2008)

I am looking at a '73 Hallberg Rassy 35 Rasmus in fairly good condition. Fuel tanks for both the Monsun 31 and Rasmus 35 are fiber glass, built into and integral with the keel instead of a metal fuel tank. A '73 Monsun new owner reported water intrusion into the fuel tank through deteriorating laminate, resulting in expensive hull repair. This condition was not detected in the purchasing survey. The new Monsum owner also reported seeing fuel leakage through the hull from a hauled Rasmus. Is this a common problem with the older Hallberg Rassy Monsun 31 and Rasmus 35? I have not read any report from Rasmus owners of this problem. Is it a legitimate concern?
DT


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## lizardheadone (Oct 9, 2007)

Maybe. I am in the middle of a complete renew on a HR rasmus. My Rasmus actually has the same problem, a leaky fuel tank on bottom edge of keel. This boat's problem looks like it had occurred from a bounce on a rock while underway or not being supported correctly while on the dry. My evidence was spider web cracks in the gel coat radiating from the area of leakage. Also, the Rasmus is built by joining two halves together. This leaves a seam down the keel. This seam is filled and faired using some type of grey epoxy putty. In my mind, this seam could be a potential area of water intrusion and thus, laminate decomposition. and in examining my boat, this is the case. There is substantial laminate decomposition along this seam in several areas along this seam on my boat. I plan on grinding and relaminating with epoxy and glass along the entire seam. There was an area of complete decompostion of about 12 inches by 12 inches at the point of the cracks that will have to be ground completely out and relaminated. One of the problems with the Rasmus's construction in my opinion is that Hallberg Rassy filled the space between the fuel tank and hull with about 1 inch thickness of very hard and what seems to be brittle and inflexible aggregate similar to concrete. This may contribute to holing of some of these tanks when the bottom is impacted. My fuel tank actually has some of its interior baffles separated from the tanks sides due to an impact. It is all fixable, but it will take some work. In summary, I don't think it is due to "bad" construction. However, I do think this type of construction is intolerant of hard knocks coming from under the keel. Don't get me wrong, I love the boat, simple and strong.


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## mitiempo (Sep 19, 2008)

Hard to say what a 36 year old HR has been through. I don't own one but would probably eliminate the tank by cutting out, repair any damage with epoxy and glass and replace with a good metal tank - stainless steel preferably. If the tank has had diesel in it for that long I don't think that you'll ever get epoxy to stick to it for just a repair.
Brian


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## Waltthesalt (Sep 22, 2009)

My 70s era HR 41 had fuel tank leakage from the in hull penetrations. The water got into the fuel tank, went to the bottom and pushed the fuel to the bilge which the bilge pumps happily pumped overboard. Big problem.


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## AnzoNevis (Nov 22, 2009)

Hmmm...I've had my Rasmus (also a 73, #170) about 11 yrs and this is the first time I've ever heard of the problem, and here it is twice. I suspect the boat had a really hard knock or even drop. I did have a problem when I thought it would be great to mount a 2nd bilge pump in the sump, dumbly drilling a hole in the aft section of the sump, thus inviting whatever was in the tank into the bilge, and worse yet, vice versa. If you're thinking about putting in a steel tank, I'm sure you've noted the fairly major surgery that would entail.


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## lizardheadone (Oct 9, 2007)

"I suspect the boat had a really hard knock or even drop" Yes, I agree with AnzoNevis that it took quite a hit to damage the fuel tank. I don't think this is a common problem, at least I haven't read that it is in all my internet searching. My Rasmus was a project boat that looked like it may possibly had seen a storm near shore.


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## hgv50 (Mar 23, 2010)

This is the first time I have heard about this problem. It sounds to me like a problem of a particular boat due to damage and insufficient repair.

In our HR41, we did have a 1 inch spot where the gelcoat was missing inside the tank. Looked as if somebody dropped a tool and chipped the coat. It was easily fixed.
There is no way I would try to fit a steel tank inside the fiber glass tank.

*Waltthesalt*, what are the "in hull penetrations" you refer to? 
The only penetrations of the fuel tank I have ever seen on both the Rasmus and HR41 are the ones in the manhole cover. If you have other penetrations, I am convinced they have been fitted afterwards.


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## 1Vagabundo (Apr 9, 2007)

I have owned a 1974 31' HR Monsun for the last 3 years.

No problems with integral fuel tank.

Have met many other HR owners and this is the first incidence of a problem with fuel tanks. As other posts have indicated it's likely not a universal problem.


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## mitiempo (Sep 19, 2008)

Here's something I only found out recently. Biodiesel should not be used by anyone with an integral (or other) fiberglass fuel tank as it eats the resin and destroys the tank. Resins have been developed only in the last few years for producing tanks for biodiesel. This information comes from Steve D'Antonio, a regular contributor to Professional Boatbuilder and is very reliable.


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## oaklandsailor (Mar 24, 2010)

Hey guys,

Thanks for this thread, as I will be looking at a '74 Rasmus (35') this week, and so learning a little about the boat in advance is far better than knowing nothing. Any "heads up" you care to offer will be much appreciated. One thing I do wonder about is that it has a wood mast and boom which I assume are original. Also, it will need extensive engine work; a rebuild at least. My purpose in buying this boat or any other is to spend a year or more cruising the south Pacific and perhaps as far as Thailand from California. All things being equal, would a Rasmus 35' qualify for this type of voyaging?

Thanks for reading.

OS


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## lizardheadone (Oct 9, 2007)

I am getting close to trying a fairly extensive repair on the fuel tank on my Rasmus. I posted above that it did have damage from an apparent grounding. I am documenting the rebuild on this boat and have pictures and drawings of the exact problem with my fuel tank if this will help anyone concerned. Again, I don't think this is a common problem, but the design of this boat lends itself to tank damage IF there is a very hard bounce on a very hard bottom. See the 2009 and 2010 Projects pages at lizardheadone.com for pictures and comments on this subject. I will post more pics and comments as I go through the repair.


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## 1Vagabundo (Apr 9, 2007)

oaklandsailor said:


> Hey guys,
> 
> Thanks for this thread, as I will be looking at a '74 Rasmus (35') this week, and so learning a little about the boat in advance is far better than knowing nothing. Any "heads up" you care to offer will be much appreciated. One thing I do wonder about is that it has a wood mast and boom which I assume are original. Also, it will need extensive engine work; a rebuild at least. My purpose in buying this boat or any other is to spend a year or more cruising the south Pacific and perhaps as far as Thailand from California. All things being equal, would a Rasmus 35' qualify for this type of voyaging?
> 
> ...


To my knowledge the Rasmus would have been originally equiped with a high quality, annodized aluminum mast/boom by Selden. Not wood.


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## lizardheadone (Oct 9, 2007)

Check this site for HR Rasmus rebuild. May contain info that is helpful.
lizardheadone.com


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## HenryMonsun (Nov 26, 2011)

I have a 74 HR Monsun, and have not seen that problem. But the integral tank makes cleaning difficult. In an old tank like this it is not surprising to see lots of sediments (brownish muck). Access is really limited, and I would like to get to the bottom of this, literally. I found that this brown stuff easily dissolves in Acetone or methylene alcohol. But in order to really flush the tank I would like to put a proper inspection hatch. There is space for that under the engine shaft, maybe 3x5''. I would pull the shaft, empty the tank and put a proper hole in there and then machine a fitting lid with a good seal. From what I see here there are people who have gotten inside these integral tanks. What can I expect when I start sawing in this inspection hole?


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## celestialsailor (Apr 28, 2005)

oaklandsailor said:


> Hey guys,
> 
> Thanks for this thread, as I will be looking at a '74 Rasmus (35') this week, and so learning a little about the boat in advance is far better than knowing nothing. Any "heads up" you care to offer will be much appreciated. One thing I do wonder about is that it has a wood mast and boom which I assume are original. Also, it will need extensive engine work; a rebuild at least. My purpose in buying this boat or any other is to spend a year or more cruising the south Pacific and perhaps as far as Thailand from California. All things being equal, would a Rasmus 35' qualify for this type of voyaging?
> 
> ...


I believe this is the boat I boat a year back which was in Berkeley and ended up on the hard in Alameda. There were many things wrong with her but it is all sorted out now. The engine had been run once a week or so while in the water, then allowed to sit. The carbon from the short unloaded runs expanded on the cylinder head from ambient moisture, preventing the crank from going past top-dead-center. Still, I rebuilt it anyways. 
Maybe you know some history of the boat. I'd like to know...


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## hgv50 (Mar 23, 2010)

I don't know about the Monsun, but on the Rasmus there's a tank cover which you can take off. Once out, it's a quick job to drill a hole in the cover and fit a large thru-hull with threaded cap, then replace. We did and there's a good 12V pump (with which you easily empty the tank - about 3 gallons a minute) that you can insert into the tank via the thru-hull; Rule IL500PK.


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