Where to locate a gyro?

[Deleted User YDKXO]

I'm unsure what is at the the extreme stern end of that "spoiler" cavity. If that section is built to the same specs as the the rest of the hull, and the rearmost panel is structural, then great. But if that rearmost section is built more lightly, and the rearmost panel thin, then not so good.

To answer your question here is a pic of the 'spoiler' compartment of my boat

As you can see the longitudinal stringers in the engine bay do not stretch back into this compartment

Here are 2 pics of a SK9 installation in another Ferretti 630 in the spoiler compartment and as you can see the yard has moulded 2 longitudinal bearers into the space in order to mount the SK9, presumably using the existing lateral stringer for stiffness. There may be further stiffening under the gyro itself but I dont know

These pics were sent to me by Seakeeper Europe some months ago and they cant tell me whether or not this installation has proved robust in the long term

Yes under the master cabin berth would be a possible location but it would mean cutting a hole in the flybridge and saloon floors to get the gyro in and I really dont want to do that. Also we might want the gyro running overnight at anchor and having it under the bed would make it difficult to sleep

Actually the weight of the SK9 is 550kg. I did ask Ventura to ask Ferretti what their max design weight of jetski + tender was in order to compare it to the weight of the gyro and my existing tender. They came back and said that the max design weight of the jetski was only 160kg and didnt state a weight for the tender which I immediately questioned because of course a jetski normally weighs a lot more than that. They havent come back to me on that. My existing tender weighs about 140kg which with the gyro makes a total of 690kg. I was hoping that Ventura would say something like 350kg jetski + 350kg tender which would mean at least my tender + gyro would be within the design weight for that structure

 

[Deleted User YDKXO]

What's the implication of Ventura being wrong? Are they prepared to warrant against the risk of stabiliser-induced structural failure?

Even if they were, would I trust their assurance? Btw I have checked with my insurance co (Y) and they dont seem bothered about me installing a gyro but I suspect that if there was a structural failure leading to, God forbid, a sinking they might then start asking some searching questions about the installation

 

[Deleted User YDKXO]

2) I am 90% sure that the two large openings at the bottom of the bulkhead do not exist in the stock F53, and if they were made for the SK installation, it's not something I would have wanted done on my boat!

Well spotted M and I noticed that too. My own F53 was not like that and I have no idea why this one was built or modified in this way. As you say the spoiler is supposed to be a separate watertight compartment for good reason

 

[MapisM]

at max effort one stringer is seeing a downward load (ballpark) of one tonne and the other an upward pull of one tonne.

Ok, but don't you think that cruising in rough seas could introduce also somewhat relevant twisting forces?
I appreciate that intuition alone is not enough, but I would be VERY surprised if a proper computer simulation (which I guess is the only way to make some reliable dynamic calculations?) would show that those force components are negligible...

 

[Deleted User YDKXO]

Adding to whats allready been said agreeing with JTB and MapishM --the bathing flatform locker idea in that pic looks daft
Perhsps on the 53 -no other options ?
Apart from the inherent torsonal strength issues or lack of as the numbers increase in the 63 ,what about the water tightness of the actual door /lid ?

Not sure what you mean by daft? How else could the locker lid be designed? Btw all Ferrettis with this type of spoiler compartment have hydraulic bi-fold lids which work in this way. But yes good point about watertightness. This was something that bothered me because I've had 3 Ferrettis in a row with this spoiler/lid arrangement and all of them have always been wet in this area. Ventura's solution if it can be described as such is to fit an extractor fan to get air moving through the compartment. Frankly I doubt whether this is going to keep this compartment any drier. On the other hand I would expect the Seakeeper product to be designed for a marine environment and to sit in a bilge with standing water under it

 

[Deleted User YDKXO]

I agree that you can't just ignore Nemo's advice, they have retro-fitted far more gyros than anyone else in Europe. How about asking a surveyor to calculate the forces and comment on the risk?

Yes when I learnt that Nemo had that experience, I had to take notice of their comment. Actually I did go back to Nemo and they said they would fit the SK9 in the spoiler compartment "if I wanted" but the cost they quoted was actually far higher than Ventura. FWIW Ventura are quoting €9500 for the installation alone compared to €24000 from Nemo plus Nemo quoted a higher price for the SK9 itself. I dont really want to waste Nemo's time by taking it any further with them

Good point about the surveyor. I did think about engaging a naval architect to give an opinion but I haven't got a clue who to approach

The guy at Seakeeper Europe, Filippo Tomasoni, is actually a good guy and has kept in touch with me and furnished me with info when I asked but in the end he's only interested in selling gyros so I dont know how much faith to put in what he says

 

[MapisM]

the longitudinal stringers in the engine bay do not stretch back into this compartment

Mmm... interesting. I didn't remember that, and I would have sweared that they do on both the 53 and the 57, for instance.
By chance, do you remember if they also don't stretch forward of the e/r, into the cabins area?
If so, they are probably just meant to support the engines, but are unnecessary for the structural integrity of the hull alone, whose mostly stressed area is well fwd of the e/r, btw.
Regardless, in a sense that's good news, because it implies (sort of) that the fabricated longitudinal bearers with their side reinforcements, as per your pic of the F630 installation, should not affect the hull integrity.

 

[Deleted User YDKXO]

Well spotted M and I noticed that too. My own F53 was not like that and I have no idea why this one was built or modified in this way. As you say the spoiler is supposed to be a separate watertight compartment for good reason

I'm afraid we were both wrong! I've just checked some pics of my old F53 and that same opening was there but on the other hand I dont remember there being any open hole between the spoiler and the engine compartment. This is a bit of a mystery to me unless these were pockets to store spare propshafts which was an option on older Ferrettis

 

[Deleted User YDKXO]

By chance, do you remember if they also don't stretch forward of the e/r, into the cabins area?

There are certainly longitudinal stringers in the forward part of the hull but obviously not as big as the engine bearers. It could be that in the spoiler, the prop tunnels (actually more like hull indentations than prop tunnels) which you can see protruding on either side, have the longitudinal stringers moulded into them

 

[Deleted User YDKXO]

As you know I would prefer fins and the 0.8msq sleipners under crew space or aft of master cabin would be uber feasible because they have very low profile actuators. These are what we fitted a year ago to my brothers Silver Dee, on same quai as your boat and you're welcome to look at them. But I appreciate the benefits of gyros too, and don't wish to turn this into a gyro v fin debate so will stick to your gyro scenario

No I dont want to turn it into a fins v gyro debate either but FWIW I am leaning towards a gyro because (I think) I have the perfect location for a gyro in that spoiler compartment and whilst it would be nice to have stabilisation under way, my main reason for looking at stabs was for stabilisation at rest. I did look at the aft end of the master cabin for the location of actuators but it would mean losing some locker space on one side and moving an air handler on the other. Again not major stuff but dropping a gyro into the spoiler compartment just seemed easier (and I believe cheaper overall)

2 structurally I would be amazed if Nemo are right. The forces here are up and down on the two stringers that the gyro needs to sit on, and those stringers are or would be made big enough, and would be between the transom abaft and the bulkhead in front. It would need to be looked at but it is verging on implausible for memo to say they can't deal with the gyro's forces.

I tend to agree but I really want somebody with knowledge and experience to say yup no problem put the gyro there

3. Water tightness of the hatch lid is an issue.

Yup as I said on another post it does always seem to be the case with these Ferretti spoiler compartments and replacing the hatch seal would certainly be on the to do list if I fit a gyro down there.

I would want to know who Ventura are subcontracting to because they won't be doing it themselves but there must be plenty of good installers they can use and this is not rocket science

Ventura say they have their own yard in Barcelona which I must admit came as a surprise to me and their own guys will do the fitting

 

[[2068]]

...in a sense that's good news, because it implies (sort of) that the fabricated longitudinal bearers with their side reinforcements, as per your pic of the F630 installation, should not affect the hull integrity.

So, what you are saying is ... there's a greater chance that 550kg of Gyro plus the rear spoiler will separate and spin off towards the seabed of the Med because it's not actually attached to an extension of the engine bearers, but if it does happen, the boat is more likely to stay intact intact and afloat

I think PBO should test up a "crash test Mobo" fitted with an out-of-control Gyro to find out where the limits are

.

 

[Deleted User YDKXO]

So, what you are saying is ... there's a greater chance that 550kg of Gyro plus the rear spoiler will separate and spin off towards the seabed of the Med because it's not actually attached to an extension of the engine bearers, but if it does happen, the boat is more likely to stay intact intact and afloat

Yeah and my mooring fees will go down too

But I wont be able to steer

 

[Portofino]

Not sure what you mean by daft? ---- 1

2---- On the other hand I would expect the Seakeeper product to be designed for a marine environment and to sit in a bilge with standing water under it

1--I ment the instal from the pic of the 53 --not the locker concept -- that s a clever use of space welldone ferretti .
But that opening to the next compartment fwds is a bit "daft " in the 53 -how ever irrelivent here

2- ah now we have seen pics of the 62 your boat -and a gyro fitted ,in a custom box. There was /is a bilge pump --
And seen a couple of quotes miles apart --looking at pics it seems robust in there rarther boxy sections aside where the bonding strips are .
Could be ok with the caveat of keeping it dry especially anything electrical -

Would you run the Geny at night --how intrusive is it ?
Last Year next to my boat @Arie d Booms yard in La Rague ,watched them install curved fins in a Riva Ego 68 iirc .
After drilling the TT hull hole s and glassing up the inside fitting the fin tubes they used a folk lift to lower the actuators on chaines - through the companionway hatch .Did not see inside so can,t coment on what furnature was ripped apart .
Blokes on it every day over 2 weeks or so .Imagine they ripped up a lot of the saloon ?
Owner told me wife did not like it choppy and was seasick a lot . Boat was pretty new and unmarked .
I wished him well with that one !

Ideally ask F to show you " one prepared earlier " the older the better .
When I was enquiring about Itamas they were quite happy to arrange for me to view exsisting local customers boats .
Wether owner knew or not --not my problem .
How ever this time you need to have a conversation with the owner (s) re repair bills originating from a damp enviroment
Oh and is it worth it .

 

[Bouba]

I would think that the best place is forward of the transom. Do you consider the bulkhead between the jetski locker and the engine room to be the transom? Or is the transom aft of the jetski locker?

 

[MapisM]

This is a bit of a mystery to me

+1!
Though coming to think of it, I might be mixing up with the 57...

 

[MapisM]

So, what you are saying is ...

Perleeease... You know what I was saying, dontcha?

 

[[2068]]

Perleeease... You know what I was saying, dontcha?

Yes, although i still think an "ultimate load destruction test" would be fun to engineer and observe, from a safe distance

 

[Nick_H]

As you can see the longitudinal stringers in the engine bay do not stretch back into this compartment

I guess that explains why Nemo didn't recommend fitting the gyro in there. I certainly think you'd need to build in new stringers between the transom and bulkhead in the spoiler, as per the pictures Seakeeper sent you, and these would need to be structural extensions to the existing stringers rather than just carriers for the gyro.

Do you know if Ventura have allowed for that? If so, then their installation quote seems very keen.

On the weight issue, do you know what kind of jet ski is designed to go in the spoiler? I vaguely remember you could only fit the stand up type in there, which probably do only weigh 160 kgs, but this may have been on the smaller Ferretti models. If so then you are putting a lot more weight in the spoiler than was intended, with implications for strength and trim.

Is there any way of contacting the owner of the 630 with the gyro installed, they may have had some design work done that you could blag or buy off them.

 

[benjenbav]

Does the bulkhead do anything beyond keeping the water out of the engine room?

If not, could you cut and shut it to allow the gyro-install to be carried out from the spoiler area, the weight of the gyro to be moved forward and mounted on the existing stringers?

Without unduly wishing to channel Prince ("23 positions in a one-night stand") this might give you the benefits of both positions ##1&2.

 

[Bouba]

On the Seakeeper website they show a unit being fitted on the deck with nothing but adhesive. Now it's a smaller unit but a smaller boat so all forces are relative. So does it need transverse AND longitudinal stringers?