Blue Angel (Canados 70s) Rebuild thread

[BartW]

Can I see foam in between the GRP the cross section of the stern opening?

yes, the green part seems like PU foam,
and the brown part seems like fibreboard, but its quite soft

remember this is the frist model range with GRP hull that Canados made,
perhaps they wanted to copy the isolation, thickness, stiffness, from a wooden hull (?)

 

[BartW]

Coming along really well Bart.

As you say, true craftsmen. I would have kittens with someone cutting holes in the transom but I guess not too bad when you have these top chaps on the job.

I hope they are going to clean your engine room when all's finish. Looks a little dusty

With regards your washing machine, there is normally a few cm between the outer casing and the machine internals, filled with insulation. Could you look at cutting down the external casing on the top corner which will then be up against the stair underside?

yes lots of cleaning to do for Alfonso,

good idea about cutting the washing machine,
using a grinding wheel on the old Aristona machine will help me to get it in there

actually the dirty room is the Utility room (space behind the engine room),
I almost forgot about the work in the ER.

there used to be acoustic foam, covered with a perferated metal grill on the ceiling. The foam was completely dried and crackled, due to age and high temp inside. Small back/grey partikels came through the metal grills, so we decided to replace this acoustic isolation.

Alfonso took off the metal grills, and old isolation.
in this first pic, you can, see some of the orriginal metal grill, behind the passerelle

I'm not yet sure about how to make the new isolation, prefer to make it is it was: but use Stone wool for absorbtion, and then new aloy perforated grills, works good and looks clean.

 

[vas]

I'm not yet sure about how to make the new isolation, prefer to make it is it was: but use Stone wool for absorbtion, and then new aloy perforated grills, works good and looks clean.

hm, nice idea, I have the same failing setup and want to renew it.
I think its called rockwool and there are different densities of the stuff 100, 300kg/whatever_don't_remember.
Else there is ricofon or something like that but I guess it wont last long in that heat....

Let us know what you finally use there so I can copy you

V.

 

[AndieMac]

I'm not yet sure about how to make the new isolation,

I hope you are just thinking out loud Bart, because if Belgium's finest acoustic engineer can't work it out.......

 

[BartW]

I hope you are just thinking out loud Bart, because if Belgium's finest acoustic engineer can't work it out.......

Ha ha Callum, I’ve contacted that Belgium company you mentioned about,
but they say that they don’t have time, as their CEO (the acoustic specialist) is too much occupied with some private matters

 

[BartW]

I think its called rockwool and there are different densities of the stuff 100, 300kg/whatever_don't_remember

Indeed its Rockwool, I didn't expect you knew that brand, I thought it was a typical BeNeLux product

80 to 100kg/m3 is OK,

but I would like the version with a black tissue on top, (as used in ventilation ducts) but this version is not generally available, especially not for a few square meters.

might use standard rockwool, and put a seperate non woven, fire resistent tissue between the rockwool panels en the alum grill.

have the products available here in Belgium, but would like Alfonso to do the work in Italy,...
and the volume of foam is too big to send it from Bel to Ital

 

[vas]

Indeed its Rockwool, I didn't expect you knew that brand, I thought it was a typical BeNeLux product

80 to 100kg/m3 is OK,

but I would like the version with a black tissue on top, (as used in ventilation ducts) but this version is not generally available, especially not for a few square meters.

might use standard rockwool, and put a seperate non woven, fire resistent tissue between the rockwool panels en the alum grill.

have the products available here in Belgium, but would like Alfonso to do the work in Italy,...
and the volume of foam is too big to send it from Bel to Ital

unless I'm horribly wrong, rockwool is a building material NOT a brand name...
check around in Italy, should be able to find it in building material merchants me thinks!
Also iirc it is fire resistant (maybe slightly off in that)

V.

 

[MapisM]

unless I'm horribly wrong, rockwool is a building material NOT a brand name...

Correct afaik, though I can't rule out that some company might have registered that in Belgium (or in any other Country whose language is not English).
Just in case Bart would like to explain that to his man in Rome, it's called "lana di roccia" in Italian.
Easily available also around here, of course.

 

[jfm]

I may be wrong but i thought rockwool was a ceramic (hence fire resistant) based fibre made into thick sheets, and is for heat not sound insulation, esp high temperatures. For sound insulation you need something with much more mass per sqm, don't you?

 

[vas]

I may be wrong but i thought rockwool was a ceramic (hence fire resistant) based fibre made into thick sheets, and is for heat not sound insulation, esp high temperatures. For sound insulation you need something with much more mass per sqm, don't you?

correct as always, but there is a 300kg/whatever that is quite dense and used sucessfully on both cases. Usually comes in hard(ish) 2X4ft sheets and 50mm thick. Quite expensive though!

need to check how it behaves in hot dump conditions, will ask and come back to you. Mind you Bart, I've never seen it lined with a black membrane as you mention. I assume you're going to cut strips and stuff it between the trusses and then cover it overall with something? THEN you screw the perforated alloy sheet? I guess you could skip this last stage if the black sheet cover is strong enough and nailed in the trusses

V.

 

[AndieMac]

but they say that they don’t have time, as their CEO (the acoustic specialist) is too much occupied with some private matters

Is it a case of 're-inventing the wheel' with existing available efficient sound insulation products, or is there still room to create/market something special for your own, and perhaps other boaters applications Bart?

 

[BartW]

A very brief an simplified explanation:

There is a distinct difference between sound isolation and sound absorption,

Isolation , creates a barrier between 2 volumes or 2 rooms
fe between the Engine room and the saloon,
Or between the inside and the outside of the generator case

Sound absorption wil damp the reflections in a room, (less sound pressure)
Fe. In your bathroom the sound is loud and harsh, as all the surfaces are hard and reflecting
In your living room the sound is soft (unless modern architecture) curtains, carpets, sofa’s will absorb sound reflection and make the sound damped in the room.(less sound pressure)

Sound isolation can basically be achieved with mass, preferably non resonating mass,
A thin steel plate will resonate, (create more sound at certain tones) so not ideal
lead, rubber, sand, cartboard, etc, has high mass, and won’t resonate,
Often used in combination with a layer of foam or rockwool type of material, to create a spring mass system, for even better sound isolation.

Sound absorption can be achieved with porous materials such as synthetic foams, stone or glass based wool, thick fabric curtains, carpets,..
Actually the density is not very important,
if you want to absorb lo frequencies, you need not only higher density material, but also very (unrealistically) thick sheets,
instead you can add a thin layer of lead, or perforated alloy plate, or a wooden panel, ore any membrane type of material will damp the lo freq reflections to a certain extend (this part is a lot more complex than here explained (re wavelength…)


practically for the ceiling of my engine room,
if I want more isolation to the saloon I could glue sheets of rubber to the wood ceiling, but this effect is very small, as the existing ceilings isolates quite good.
but more important I want to damp the sound level inside the engine room this will also reduce sound going through the celing.
Therefor I want to place a layer of rockwool on the ceiling,
covered with a aluminum grill to get some lo freq damping, but mainly for the mechanical protection of the rockwool. (and the perforated plate finish looks nice )
The rockwool needs to be covered with a sheet of fabric, or any other acoustically transparent film,
To prevent stone wool particles coming loose and falling in the room.


Some info about Rockwool
It is a multinational company, that operates under different names in different industries / product groups (also marine industrie)
Their main product is a “stone wool” based sheet, for thermal and acoustic isolation / absorbtion.
Here is an overview of their business.

http://www.rockwool.com/about+the+group/the+group+in+brief/business+areas

some more info about rockwool and acoustics:

http://www.rockwool.com/acoustics


apart from Rockwool,
There are other materials available specifically made for the treatment of a boat engine room / genset, …
We went to a specialized chandler to select them, but the ones that I found had:
A external metal toplayer (film) , that make them too reflective (not absorbing the sound inside the E/R)
Or
just a very expensive fire resistant foam (no added value compared with simple Rockwool)
So I didn’t find the perfect material, and for now I stick with Rockwool .



Pffff so much bla bla bla for a simple E/R ceiling covering, yes I agree a bit out of proportion

 

[AndieMac]

Pffff so much bla bla bla for a simple E/R ceiling covering, /QUOTE]

I don't think there are too many mobo owners that are 100% happy with engine noise levels on their boats Bart.
I think you'll find others are interested in reducing noise levels without spending a fortune

 

[vas]

Pffff so much bla bla bla for a simple E/R ceiling covering,

I don't think there are too many mobo owners that are 100% happy with engine noise levels on their boats Bart.
I think you'll find others are interested in reducing noise levels without spending a fortune

definitely +1

The rockwool needs to be covered with a sheet of fabric, or any other acoustically transparent film,
To prevent stone wool particles coming loose and falling in the room.

Bart, I'm following all argumentation here, but I'm confused on what is the right material for this acoustically transparent film and it's mechanical properties as far as adhesion to rockwool, if any, as we may assume that being sandwitched between plywood floor, rockwool and perforated alloy sheet is enough
Care to also comment on the size of holes for the alloy grill?
Have you actually measured freq in your salon and trying to "tune" this alloy sheet for specific frequencies, or a typical 6-10mm hole sheet will do?

cheers

V.

 

[BartW]

I'm confused on what is the right material for this acoustically transparent film and it's mechanical properties as far as adhesion to rockwool, if any, as we may assume that being sandwitched between plywood floor, rockwool and perforated alloy sheet is enough

Care to also comment on the size of holes for the alloy grill?

Have you actually measured freq in your salon and trying to "tune" this alloy sheet for specific frequencies, or a typical 6-10mm hole sheet will do?

V,
Actually the only reason for this film / fabric is prevent rockwool particles falling through the grill. (due to vibration and age )
Rockwool has these panels available with a black covering ao for usage in airco ducts
But we could just as well use a separate fabric that is fire resistant. As you say, It is sandwiched between the Rockwool and alloy, so no real need for adhesion

For the alloy plate
Rule of thumb is to have at least 40% perforation, then the panel acts on mid and high freq as a 100% absorber. I just discovered that the old panels have only 25% perforation,
So there we could improve absorption a bit, to damp that ear bleeding noise when the engines are running.

This alloy plate has only a very small contribution to the low frequency absorption,
Its very difficult to calculate the absorption and res freq. of a vibrating panel, as it is not only the mechanical properties of the panel that counts, but also the size and the fixing, and the positioning of the panel.
f.e. in corners they work much better…
Also adding a damping wool, will decrease the absorption effect, but widen the freq. range.
Actually everything that vibrates will absorb some lo freq sound energy.
But the good thing is that we are used to more lo freq reflections, longer reverb times at lo freq. so these are usually not a problem, unless you're working on Music

 

[BartW]

OK then, We’re in business for a retrofit hi lo platform, (sorry for that MapisM )
A project drawing will be made by h-b technics next week, I have to take some dimensions when I’m at the boat.

One remaining question:
should I use the standard GRP moulded platform from h-b; 4,5m x 1,5m (4500,-euro for the GRP and 4000,-euro for the teak)
Or should I have a custom made GRP moulding in the yard in Italy ?
The latter could be better (esthetically), but
I guess it will be more expensive. I could asc a quote next week.

The existing platform on BA is 4,65m wide on its widest point
Height of the h-b platform can be adapted, but it has more square corners, while the existing has more rounded corners.
H-B can provide detailed drawings for mounting a custom made platform, but all from one supplier has some advantages

Existing platform

h-b 4,5m wide standard platform

Mounting area for the system

the total weight of the mechanism, and platform and accessories is 500kg,
Max total weight (including a tender fe) is 1000kg.

any other remarks that I should take care of ?

 

[jfm]

Nice stuff Bart. The HB platform might be ok, but it depends on lots of details. Do they charge €4k just for the teak? Sheesh; I would think 1500 would be enough

You will need to have big stand-offs made because your transom is set in a long way from the aft edge of your existing platform. These need to be made from big heavy s/s plate

FWIW here are some close ups of the sq78 HB technics job (I have lots more pics if you want)

 

[BartW]

Do they charge €4k just for the teak? Sheesh; I would think 1500 would be enough

its a little bit less, but 570euro/m2 for 10mm Teak, including these openings, seems quite ok from Germany not ?
(platform is 4,5 x 1,5 = 6,75m2)

the Italian gang quotes 500e/m2 for doing the boat (don't worry,I won't)

You will need to have big stand-offs made because your transom is set in a long way from the aft edge of your existing platform. These need to be made from big heavy s/s plate

exactly,
appart from the standard
"type 4 lift system",
a Set of
"SST-mounting box, special designed for Canados 70" is needed

communication with HB is very good !
so lets see what they come up with.

In your first pic , on SB side just below the platform,
is that a fixed ladder for climbing from the lowered platform on the fixed platform ?
Is this partially submerged when the boat is not on the plane ?
Have been thinking about such a step, as in my case the existing platform is 60cm above WL, which is too high to climb on without a ladder (when the HiLo platform is in its lowered position)

 

[Deleted User YDKXO]

Fantastic, work, BartW. Its always a pleasure for me to see craftsmen at work. One question though. Why did you remove the remote fridge compressors? This is a similar system as what Ferretti fit and I think it works very well. Certainly it keeps the noise and the heat from the compressor out of the accomodation and the fridge cooling efficiency, at least on the Ferrettis we've had, has been excellent

 

[jfm]

In your first pic , on SB side just below the platform,
is that a fixed ladder for climbing from the lowered platform on the fixed platform ?
Is this partially submerged when the boat is not on the plane ?
Have been thinking about such a step, as in my case the existing platform is 60cm above WL, which is too high to climb on without a ladder (when the HiLo platform is in its lowered position)

Yes it is a ladder for that purpose. When the boat is at rest it is mostly submerged, so it gets covered in barnacles. I don't have the ladder on my boat and I just climb up. If the platform is very low it is a big climb but normally we have the platform level with the water when swimming, and the climb is only (about ) 40cm so it is easy

There is no right/wrong answer. Sunseeker also fit these ladders and lots of people must like them, but i didn't want one.