Trim tabs and underwater exhausts

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simonjames

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Finally after a lot of boats viewed we've found the model we want. Thanks to everyone for your help. We've decided on the Jeanneau Prestige 50s. We've found one in France and are off next week with a view to buying. I've noticed that the Prestige does not come with trim tabs as standard. I'd like to know your thoughts on this. Also the boats have underwater exhausts can anyone inform if there any advantages/disadvantages to this system, other than less noise and exhaust smell etc. finally the boat is offered on a French Jeanneau agents site and states that the boat will be freshly anti fouled and engines serviced prior to handover. The boat comes with a 2 year eyb. Warranty has anyone had any experience of dealing with issues with these warranties, and is it usual practice for a brokerage boat to have all this, as I thought it would only be dealer owned boats.
 
Congratulations Simon, even if a little premature!
You will need trim tabs, are you sure that the boat does not have them? I would be a little surprised. If not then get them specified as a condition of purchase...that boat will ride well in slack conditions but a strong current/cross wind will have it leaning and tabs will be a must. Also at 50' you will find that a play with the tabs will allow you to take sea at faster speeds when sea States worsen. My experience in smaller boats is generally that you slow down and get the bow up and dolphin along but in the bigger boat the extra reach and stability will mean that you can trim the bow down and land the nose on the swell before you come down all the way, depending on the sine.....
Exhausts, well I think you have answered that one in the question, noise and smell! But there are those far more knowledgable that me who may know otherwise.
I know it's very suck eggs but make sure to get the best survey, hull and all...

No idea about the warrantee....

Will you be keeping the boat in France?



Have a great trip and bring back some photos......
 
Hi There
The boat has the control but no trim tabs, it's strange as I've seen 4 for sale without them, I looked at one for sale at Swanick and was told by the broker they didn't need trim tabs as the hull shape countered the need but from my very limited experience of messing around in a 19ft bayliner years ago trim adjustment on the leg was a great help (speed and conditions wise). As for where the boat will be kept it is going to be kept on my berth at Port Ginesta in between Barcelona and Sitges
 
Does seem strange, I would have a good look into that....I guess that you can fit for a couple of k after the sale but I would be surprised if tabs did not make a good deal of difference. Prestige may have a great balance with that hull and from what I have seen it does ride well with a comfortable rise but with wind or current coming at anything other than dead ahead or astern and the boat will lean, esp with the roof open!

It's crazy that trim tabs are an extra option on boats like this, doesn't do the manafacturer reputation any favours imho. But they all seem to be at it....

Lovely area, drove the coast road last Chrstmas on a reccy to San Carles, may see you over there in a couple of years :)
 
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IMO underwater exhausts shout of a manufacturer cutting corners and not wanting the complex job of routing exhausts correctly to the stern, also the visual safety of transom exit exhausts is lost... Plus on a flybridge underwater exhausts exiting just about opposite where you sit (although much lower) can be much noisier than transom exit as when you are on the move those underwater exhaust can easily be out the water
 
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Firefly625 said:
IMO underwater exhausts shout of a manufacturer cutting corners and not wanting the complex job of routing exhausts correctly to the stern, also the visual safety of transom exit exhausts is lost... Plus on a flybridge underwater exhausts exiting just about opposite where you sit (although much lower) can be much noisier than transom exit as when you are on the move those underwater exhaust can easily be out the water
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Like I say, do not understand the reasoning/pros/cons although I think that on my boat the fumes are directed through the pods...looked pretty nicely done when I was under the casing a couple of weeks ago...
 
Really sorry but this one does have trim tabs can just make them out on photo ( difficult to see as stern thruster in way), it was the one in Swanick that didn't have them apparently they're an optional extra. From the advice I've got on here think I may have ditched the dishwasher to have the trim tabs.
 
Firefly625 said:
IMO underwater exhausts shout of a manufacturer cutting corners and not wanting the complex job of routing exhausts correctly to the stern, also the visual safety of transom exit exhausts is lost... Plus on a flybridge underwater exhausts exiting just about opposite where you sit (although much lower) can be much noisier than transom exit as when you are on the move those underwater exhaust can easily be out the water
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Hmm, not sure I agree that. The size of exhausts for big engines often makes routing them to the stern too much of a compromise in terms of lost hull volume and interior heat soak, imho. They hardly ever come out of the water underway so they're definitely quieter. Mine exit underwater at aft end of e/room and I wouldn't want it any other way (with small by passes to the transom of course, about 3 inch diameter, for when the boat is idling and stationary)

I don't get the visual safety point firefly??
 
simonjames said:
Really sorry but this one does have trim tabs can just make them out on photo ( difficult to see as stern thruster in way), it was the one in Swanick that didn't have them apparently they're an optional extra. From the advice I've got on here think I may have ditched the dishwasher to have the trim tabs.
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Ooh now that would be a tough call...:)
 
+1 on this. My Snazi exhausts under water. Routing exhausts through the Lazerette to the transom would not be very sensible imho, and I don't miss the exhaust noise at all. I dont know what I would learn about listening to the exhaust, but happy to hear otherwise.
 
Firefly625 said:
IMO underwater exhausts shout of a manufacturer cutting corners and not wanting the complex job of routing exhausts correctly to the stern, also the visual safety of transom exit exhausts is lost... Plus on a flybridge underwater exhausts exiting just about opposite where you sit (although much lower) can be much noisier than transom exit as when you are on the move those underwater exhaust can easily be out the water
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No quite the opposite. I have had flybridge boats with transom exhausts and underwater exhausts and the latter is eminently preferable IMHO. I found transom exhausts to be far noisier than underwater exhausts to the point of buying earplugs for helming one boat that I owned, a Broom 37. Then the transom gets coated in soot and unburnt fuel and needs constant cleaning. As jfm says, providing the underwater exhausts are fitted with bypasses so that you can check that cooling water is flowing, there's nothing not to like
 
Nigelpickin said:
It's crazy that trim tabs are an extra option on boats like this
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Definitely +1.
Otoh, the good news is that by buying a boat without them, one has the opportunity to fit something better than the Xmas cracker model which would surely be fitted if they were standard... :)

As an aside, simonjames, IIRC the 50' is available with both shafts and IPS.
What does the one you're looking at have? I'd rather run than walk away from the latter.
Believe it or not, not later than yesterday I've seen a (pretty recent) Prestige 42 on the hard with one of the things taken apart.
No idea of the reason, but pretty sure the number of IPS-less boats which you can see around the yards is impressive....!
 
I'm voting with my spanner. Tired of the pounding my ears get on long passages from my Detroit Diesels with transom exhausts and the constant whiff of burnt diesel blowing back onto the helm when pootling. I've been experimenting with external mufflers (modified 10" cooking pots) for two years now, using the pots to direct the exhaust in different angles. Next season I will go for a final fit using 10" stainless steel ventilation flues angled at 45* to put the exhaust into the water and angled out to the sides and into the slip wave. It does make a radical difference both to attentuated noise and vibration, and no fumes.
As regards trim tabs I guess it depends on the hull form and usual cruising speed. Mine stopped working 5 years ago and in truth their loss has never bothered me enough to put it up my priority list. The Bertram has a very well balanced semi D hull and on the occasions we feel the need for speed, the bow comes up and the lower chines slice through the waves cleanly giving a very stable ride. I'll get round to fixing them one day I guess.
My advice if you buy the boat is use it for a season and then decide if you need them, after all retro fitting will cost and it's yet another system that requires maintenance and repair.
Enjoy the boat
 
jfm said:
Hmm, not sure I agree that. The size of exhausts for big engines often makes routing them to the stern too much of a compromise in terms of lost hull volume and interior heat soak, imho. They hardly ever come out of the water underway so they're definitely quieter. Mine exit underwater at aft end of e/room and I wouldn't want it any other way (with small by passes to the transom of course, about 3 inch diameter, for when the boat is idling and stationary)

I don't get the visual safety point firefly??
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Interesting.

The exhaust noise on my boat is wearing. There are no silencers because of the aft cabin causing space issues.

I was looking to re route the exhaust and put silencers under the bed but it's a lot of work.

So why didn't sealine exit the exhaust underwater I wonder. What are the downsides, what type of skin fitting, and what's the bypass for (I could use the existing exhaust as a bypass with reduced diameter and an inline muffler I guess )
 
The bypass is to allow low pressure gasses to flow through when the engines are idling, instead of creating back pressure trying to force its way into the water. The safety aspect is that you get to check your cooling system is working when you're warming up by visually checking for water coming through the exhaust port. Your engine temp Guage performs a similar function.
Instead of tearing your aft cabin apart why not try fitting an external muffler to push the exhaust down into slip stream?
Cheap and easy to fit, easy to remove or play with if you're not happy 

Ebay 400787518111

image.jpg
 
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Elessar said:
So why didn't sealine exit the exhaust underwater I wonder. What are the downsides, what type of skin fitting, and what's the bypass for (I could use the existing exhaust as a bypass with reduced diameter and an inline muffler I guess )
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I'm guessing it was just easier to route the exhausts to the transom. An underwater exhaust obviously requires modifications to the hull moulding, a substantial grp moulding to make a connection to the exhaust and possibly a convoluted exhaust hose routing. On my existing boat and previous boats with underwater exhausts there has also been a non return flap fitted. Its not something IMHO you could consider retrofitting. In your case, firstly you could check that the existing exhaust silencer is in good condition. If you have an inline silencer sometimes the internal baffles break so possibly you could start by replacing the silencers. The next thing you could consider, if you don't have them already, is fitting water mufflers if there is space in the engine bay. An excellent company to talk to would be Halyard http://www.halyard.eu.com/pleasurecraft/index.php?page=1
 
Bertramdriver said:
The bypass is to allow low pressure gasses to flow through when the engines are idling, instead of creating back pressure trying to force its way into the water. The safety aspect is that you get to check your cooling system is working when you're warming up by visually checking for water coming through the exhaust port. Your engine temp Guage performs a similar function.
Instead of tearing your aft cabin apart why not try fitting an external muffler to push the exhaust down into slip stream?
Cheap and easy to fit, easy to remove or play with if you're not happy 

Ebay 400787518111

View attachment 46652
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Because the exhaust comes out of the side of the boat not the transom.
 
Deleted User said:
I'm guessing it was just easier to route the exhausts to the transom. An underwater exhaust obviously requires modifications to the hull moulding, a substantial grp moulding to make a connection to the exhaust and possibly a convoluted exhaust hose routing. On my existing boat and previous boats with underwater exhausts there has also been a non return flap fitted. Its not something IMHO you could consider retrofitting. In your case, firstly you could check that the existing exhaust silencer is in good condition. If you have an inline silencer sometimes the internal baffles break so possibly you could start by replacing the silencers. The next thing you could consider, if you don't have them already, is fitting water mufflers if there is space in the engine bay. An excellent company to talk to would be Halyard http://www.halyard.eu.com/pleasurecraft/index.php?page=1
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I have no silencers. And no room for them in the engine bay. I'm familiar with halyard stuff I used it when I re engined my bayliner. They need a lot of space when you take the hose turns in and out into account.

Substantial GRP work on the ther hand doesn't bother me at all. Can't be harder than fitting a Bowthruster for example, which I did. Why can't I retrofit, I just need to understand what's needed.
 
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Exhaust outlet through hull means a very short run of pipe, it also eliminates the down angle problem from the riser or elbow as many boats require an "up" from the turbo before it can drop so not to allow sea water back in the turbo.

A direct drop is easy straight out into a silencer which on most boats I've worked on is moulded to the hull.

This set up always makes me question in my own head and there all "Ifs" but should the moulding delaminate away from the hull your going to let water in, I've seen a few boats having gel repairs in this area where over years a problem has started, mainly Azimuts so I'd check yours Rafiki, water stains and rust marks seem to appear.

The other downside is that you have sea water a lot nearer your turbo with salty air and no way of blocking it off unless you remove the exhaust elbow, this will corrode the turbo housing and vanes, which is the norm on most sterndrive installation...

Elessar you could fit different risers and then the dustbin silencers in the engine bay, or copy a sealine 42/5 installation where it drops straight out the bottom .
 
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