IPS

[MapisM]

Here is an idea of the 55S technology see how the boat works well by using only two engines. https://www.youtube.com/watch?v=oxGF0UlWPWE

By chance, do you know Bulleri, W?
I can't help thinking that in most of his video he's cheating, in this or that respect.
In this one for instance, I can't believe for a second that the video is really showing a hardover steering at speed, as he pretends to be doing.
In each and every IPS boat I've seen, the listing in such maneuver is scary at best, if not downright dangerous (as indeed it was in one of the first f/b where AZ gave IPS a try, can't remember the model exactly).
And since it's a matter of physics, it's hard to believe that with this 55 they found a magic trick for almost flattening the boat without any kind of stabilization... :ambivalence:

 

[MapisM]

In truth, if you want stabilised boating (...) you ought to consider some different boats from Abs47

Hmm, not sure i agree. RD loves Absolute....

 

[PowerYachtBlog]

Thanks PY, not looking to spend that sort of money as it will sit for extended periods unused while I get dragged all over the world by Nicky !
On the Abs 47, where would a giro fit ? Is there space under the rear cabin ?
Also, do you know what years the 47 was produced ?

47 STC was produced from 2007 till 2011. There is some nice deals on these in Italy IMO, which deserve attention.
I would ask Absolute that question and see what they say. I am not sure the 47 had gyros in mind when produced.
It is possible they are available on the newer 45 STY though.

 

[PowerYachtBlog]

In truth, if you want stabilised boating (and it is a whole nuther world...) you ought to consider some different boats from Abs47, but I was answering the question you asked!

For sure, but then you have to scrub out most deep or medium Vee planning boats with the exception of some sport-fishing vessels which are meant to be stable while going fishing at slow speed.
Some of the new Viking sportfish do this pretty well, but then that would cost 50% more to the mainstream production boat of same size.

My stabilized boating is always an anchor at the back to tide direction, and makes it pretty okay.

 

[PowerYachtBlog]

By chance, do you know Bulleri, W?
I can't help thinking that in most of his video he's cheating, in this or that respect.
In this one for instance, I can't believe for a second that the video is really showing a hardover steering at speed, as he pretends to be doing.
In each and every IPS boat I've seen, the listing in such maneuver is scary at best, if not downright dangerous (as indeed it was in one of the first f/b where AZ gave IPS a try, can't remember the model exactly).
And since it's a matter of physics, it's hard to believe that with this 55 they found a magic trick for almost flattening the boat without any kind of stabilization... :ambivalence:

I know Bulleri from Facebook.

Actually the 55S has really a low lean angle which happens because of the flat part it has at the stern. Also the third central engine works as a righting keel in my opinion.
But we have a 55 S running in Malta and I seen her doing it tight turns and it really does not lean much. I would say even less to some flybridge boats with bigger then normal propeller pockets (type Sunseeker)
Now it is possible Bulleri does some tricks here and there but his reviews are okay, and I think in between the lines sometimes you can feel a bit of critic.
Not as good as Boattest.com but I think I would rate him second from the popular ones.

The first Azimut they produced with IPS was the 43S without flybridge which had a hull based on the 43 Fly.
Then in Sweden they experiment with the 50, and at a later stage the 55. They also experimented with the Altantis 55.
They also did a 62S with the large ZF pods which has a Micheal Peters hull and a dead rise of 20 degrees. This had to go as an option but interesting it was stopped.
This is my article about the 62s from 2010 http://www.poweryachtblog.com/2010/12/improve-it-azimut-62s.html

When I asked Azimut why it was not produced they told me Costs.

 

[rubberduck]

OK, I suppose the next question is to ask for suggestions as to type of boat that could accommodate some form of stabilization, pref sporty & sub 50ft, around £300k + stabs, lightly used ?

 

[Nick_H]

Isn't that why Seakeeper go for 2 smaller gyros rather than 1 large one sometimes? I still don't think they'd fit under the aft cabin of any 50ft sports cruiser but you might just squeeze 2 smaller gyros in the engine bay

An Abs 47 would only require one of the smallest model 5's anyway, so fitting two smaller ones wouldn't be an option for RD. (the model 3 is just a DC current version of the 5, with same weight and dimensions)

 

[MapisM]

OK, I suppose the next question is to ask for suggestions as to type of boat that could accommodate some form of stabilization, pref sporty & sub 50ft, around £300k + stabs, lightly used ?

Very tricky requirements. Sporty and stabilized sounds like a sort of oxymoron, in fact: weight and drag are the major enemies of performance, and stabilizing a monohull requires either a lot of the first, or a fair bit of both.
Also, I don't think it's really a matter of boaters being "ahead of builders" here, as jfm suggested.
When at Absolute they design a 47' sportboat capable of 40 knots and they don't even consider offering any kind of stabilization, they know their onions.
'Fiuaskme, you should make up your mind about what's more relevant to you - performance or comfort.
You might also go for a compromise of course (as often happens with boats), but I'm afraid that hoping to find (or modify) anything like an Abs47 which can be as comfy as Flemings etc. is wishful thinking, imho.

 

[jfm]

Also, I don't think it's really a matter of boaters being "ahead of builders" here, as jfm suggested.
When at Absolute they design a 47' sportboat capable of 40 knots and they don't even consider offering any kind of stabilization, they know their onions.

I'm not so sure. If you want to break a world record then sure you will not waste a few hundred kilos or newtons on stabilisation, but other than that customers can ask for uber performance plus stabilisation. MYAG's new Intrepid will do/have 70mph +, 4 x 7Marine 627hp, and gyro stabilisation
I'd suggest that the only reason every 45 foot sportscruiser made today doesn't have stabilisation is some sort of cost/space limitation, not weight/drag, and not onions. In other words if a gyro cost €1 and took up one litre of space, and weighed 500kg, I reckon the entire Absolute range from the smallest boat upwards would have stabilisation in the standard specification, and every existing Absolute would have one retrofitted by next weekend. So the reason these boats don't have stabilisation is just cost and space

 

[jfm]

This shows Humphree fins working well at anchor, on (I think) a manhattan 70
https://www.youtube.com/watch?v=RWk4jd9YnZM

 

[rubberduck]

Do the gyros have to be attached to the hull stringers ?
Thinking about it with our extended platform on the 41 (now 43) we could put the dingy on that & use the garage ?

 

[MapisM]

I'd suggest that the only reason every 45 foot sportscruiser made today doesn't have stabilisation is some sort of cost/space limitation, not weight/drag, and not onions. In other words if a gyro cost €1 and...

Well, I'd be very curious to see actual figures on how weight/drag of any sort of stabs can affect a 45' sportcruiser performances (both in terms of speed and fuel burn).
But I don't think the differences would be as trivial as in your, mine, Silverdee's, MYAG's or Nick_H's boats, just to name a few very different stabilized boats which - not by coincidence - are all pretty far from sportcruisers.

Otoh, I agree with your "what if" analysis, in principle. But we are now going round in circles a bit, I reckon.
If we come back to Sep 2016, you already summarized nicely and realistically in the last sentence of your post #17 what I was trying to say from the beginning, nothing else...

 

[MapisM]

Do the gyros have to be attached to the hull stringers ?
Thinking about it with our extended platform on the 41 (now 43) we could put the dingy on that & use the garage ?

One advantage of gyros is that they are effective regardless of their placement, as opposed to fins (and their actuators) whose placement has to be in a rather specific area of the hull. But you still must consider several factors:
1) the forces a gyro transfers to the hull while operating can be quite substantial;
2) the same goes for the forces that the hull can transfer to a gyro, which is a very heavy lump of metal that you don't want to fly around the boat after hitting a wave;
3) similarly to any ballast, you'd rather want the sheer weight of the thing to be placed as low, and as close as possible to the CoG.
Bottom line, in practice you have no other choice than attaching gyros to the central hull stringers, I'm afraid.
Besides, in your Abs, aren't the engines reachable under the garage floor?
If so, even assuming that it's strong enough to attach a gyro to it (which I very much doubt), just imagine what sort of nightmare would become the engines access...!

 

[Deleted User YDKXO]

Also, I don't think it's really a matter of boaters being "ahead of builders" here, as jfm suggested.
When at Absolute they design a 47' sportboat capable of 40 knots and they don't even consider offering any kind of stabilization, they know their onions.
.

I'm guessing that nobody in the Absolute design department even gave a thought to stabs during the design process probably because it never occurred to them that stabs would be something a customer would ask for. After all the nearest most designers get to actually being on the boats they design is at the occasional boat show so the idea that people might object to their boats rolling around at anchor probably wouldn't cross their minds

 

[Nick_H]

I don't know what the design and tooling leadtime is for a new sportcruiser model, but the relatively small and cheap gyro has only been available for a year, so at the time most current sub 50' sportcruisers were designed there wasn't a suitable stabiliser to include as an option even if they wanted to.

The small gyro weighs 360 kgs, about the same as a 4 stroke jetrib with fuel, and I've seen jetribs on boats under 50 feet a number of times. I had one on my T46, admittedly the old 2 stroke which was 100 kgs lighter, and I don't remember a big impact on speed, and of course the jetrib overhangs the transom whereas a "designed in" gyro would be further forward and better balanced.

I imagine we'll start to see them being offered as an option on sportcruisers fairly soon, maybe as an either/or option in place of something else to avoid the space being wasted on non-gyro boats.

 

[Deleted User YDKXO]

I imagine we'll start to see them being offered as an option on sportcruisers fairly soon, maybe as an either/or option in place of something else to avoid the space being wasted on non-gyro boats.

For sure. It will be a major competitive advantage for any builder to be able to offer a factory fit gyro (or fins on larger models) as an option across their range of boats very soon and any builder who doesn't do that is going to lose sales as a result. I could definitely envisage a time when new boat buyers tick the gyro option box as readily as they tick the box for a generator

 

[TonyR123]

interesting comment about losing sales if not an option. Currently in market for 50ft flybridge and a 'must have' is a gyro for me. first and foremost. if I cannot have one fitted then no matter how good the boat is I would not purchase it.

I know the manhatten 52/princess 49 is offered with them and can be after market fitted to a prestige 500. They produce alot of force so would not want it installed anywhere else than on the main hull stringers!

 

[TonyR123]

Also for IPS - arent they are alot more complex so alot more can go wrong? Also have been told that they slow down more than shafts with some growth on them. So once cleaned similar speeds, but with say 6 months Med growth they slow down alot more?

Having said that I still think I want IPS for the extra room if nothing else!

 

[PowerYachtBlog]

Also for IPS - arent they are alot more complex so alot more can go wrong? Also have been told that they slow down more than shafts with some growth on them. So once cleaned similar speeds, but with say 6 months Med growth they slow down alot more?

In the best of Summer July to September, sea temperatures at 25 degrees + having two weeks without use, will result in a lot of growth to the props. Not six months!
In six months you think your dives have been replaced by nature loving sea trees
So you will need to dive yourself or get a diver to do it for you if are keen on having 90-100% of performance nos.
If the boat is just powered right this will be an even growing concern.
15 tons and IPS600 Volvo D6 435hp as an example, and 25 knots cruise become 20 and fuel burn as much as a shaft boat three meters larger, and 30 percent heavier.

I tried Propspeed once on IPS and it not work, which works brilliantly on shaft bronze propellers.

 

[Nick_H]

interesting comment about losing sales if not an option.

Not just losing sales, a stabiliser option can create new sales by itself. I was told by a major new boat dealer that their biggest single sales stream is persuading existing customers to upgrade, but to do that they need a killer new feature that the customer can use (in a man maths kind of way) to convince themselves that the purchase is justified. It seems the vast majority of customers would rather upgrade than retrofit.