Stern drive back flooding through the exhaust

[Boating]

I am purchasing a Nimbus 29C with a Volvo AD41B stern drive. I have been told by the surveyor that in it is possible that circumstances could lead to back flooding of the engine. And that a dingy should not be placed on the bathing platform and that it is unwise to keep the boat on a swing mooring.
IS THERE A PROBLEM WITH STERN DRIVES AND BACK FLOODING? If yes is there a modification kit?

 

[duncan]

sounds like he is unhappy with the relative heights of the exhaust elbow and the water levels.

I would pass his comments on to Nimbus customer service, or the UK dealership, and ask them to take it up with him direct as he seems to be implying that they have produced an unsound boat!

there are thousands of boats out there with this sort of set up - many with exactly that engine and drive.

Please follow it up and let us know the outcome - he's eithr an excellent survayor who has spotted an unusual/faulty installation or.............

 

[A_8]

I think he takes it to far...unless the boat for some other reason is to deep in the water which is what you then need to focus on.

 

[boatmike]

Rather than posting this on here and generating a lot of speculative replies that could be entirely misleading you should ask the surveyor why he has made these comments and what to do about it. That's what you pay him for, not just to write a vague report with unexplained findings.

 

[scej]

from memory i thikk that you will find on the exhaust bellows between the transom plate and drive there is a non returnn flap in them, som of teh earlier drives also had rubber flaps on the exhaust. some of the down tubes fitted also had a retun flap fited in the top of the tube. I would check the exhaust tube inside as these have a habit of corroding and teh internal bellows come off and you get some water coming in!!! how old is the boat?

 

[alb40]

I agree with boatmike. Your paying the surveyor to advise on potential problems - so badger him for his advise on a solution.

 

[andy_wilson]

That's not entirely fair.

Every surveyor will balance a one line 'finding' with 8 pages of caveats and disclaimers at the back.

The poster was very specific about the vessel type, installation and issue.

Not unreasonable to seek other opinions or specific experience, perhaps to challenge the surveyor with.

IMHO

 

[jimg]

According to the Nimbus web site the Nimbus 29 Coupe was made between 1989 and 1997, I would imagine in that time a major design fault would have shown up?
I have owned a Nimbus 345, Nimbus 380 Commander and now a Nimbus 26 Nova. They are well built boats and I would be suprised if there was a serious design fault, I would ask your surveyor for more information.
What year is the one that you are looking at?

 

[Boating]

Duncan
Thanks for the e-mail. Before posting my message I had sent an e-mail to Nimbus HQ. Volvo HQ, Motor Boat Monthly Mag. and a Volvo dealer in this country. That was a week ago and none of them have replied. I am still working on it with the surveryor who things he can get a conversion done for £1000. My issue is that the baot is 12 years old and no one seems to have any record of problems with other boats.

Anyway thanks for your contribution.
Alan

 

[Boating]

Scej
I believe earlier models did have a flap in the exhaust but not in the AD41. The boat is 12 years old.
Thanks for your contribution.
Alan

 

[Boating]

jimg
The boat is 12 years old. Unfortunately I have been unable to get a reply from Nimbus. I will try to get some answers at the boat show. Like you I think the Nimbus is a nice boat and have decided to take ownership on Saturday and will sort this out later. I have also signed up for the Nimbus owners club hopefully this may assist once I get a reply from them.
Thanks for your contribution.
Alan

 

[danielbroad]

This just all seems highly odd - how far below the water is your stern drive? - on my installation it just touches the surface of the water and the exhaust elbow is miles above water level.

Daniel.

 

[duncan]

small word of warning - whilst I would take some comfort that a 'solution' exists for a given amount of money I would not actually undertake the work without Nimbus written opinion.

I had 2 similar changes suggested by a marine surveyor on a new boat that had come to the attention of the insurers. One had to be undone (non return valves in the cockpit drains) as it caused more problems than it was purported to resolve and the other, installation of a stop cock in the water feed from the outdrive leg (my installation had both this and a direct engine pick up) caused so much consternation amongst the Mercruiser mechanics I approached that I actually forwarded written material to the surveyor about the potential danger he was puttting people in from the recomendation - basically you trade a very small possibility that the boat will sink whilst unattended with catastrophic drive failure whilst in use on passage (if you fail to open it or anyone else uses the boat and is unaware of the obscure installation of such a seacock/valve).

Still interested in exactly what he is recomending and why but you should definitely call Nimbus or a UK dealer.

 

[jimg]

It might be worth calling Offshore Power who are the UK agents and try to speak to Richard, who is the technical guy and knows a great deal about Nimbus boats.