Blue Angel (Canados 70s) Rebuild thread

[rafiki_]

Bart, my comment would be to question to costs of the stairway mouldings. This would be a one-off pattern, with no other sensible use. In order for the stairway to be sympathetic to the craftsmanship in the rest of your boat would imply quite an expensive mould, in addition to all the local detailing work to ensure that the new stairway fits seamlessly with the transom. You then have potential issues with gelcoat colouring. Matching to BA after many summers UV attacks will be challenging. Even if you can match now, the new moulding and transom changes are likely to deteriorate at a different pace from the original material, so in a couple of years time, the changes could be very apparant.

In conclusion, JFM's stairway would not require a mould, and would need minimal changes to the current transom, giving you fewer long term issues with colouring too.

 

[vas]

something anyone designing staircases should know is the basic step calculation rule:

0.60m =< 2 X riser + step =< 0.64m

works from outdoor layouts with 10cm risers up to 30cm risers on boats
shoving one step under the other messes only the way downwards, climbing is still absolutely fine.
Hence the very steep designs like the two next pics, the first one could be a solution to Bart's problem if carefully designed. Does look a bit confusing in the pic though, will try to find a better one.

V.

 

[jfm]

something anyone designing staircases should know is the basic step calculation rule:

0.60m =< 2 X riser + step =< 0.64m

I think your formula is a (non naval) architectural rule, for houses and public buildings, but it doesn't apply to boats.

If the riser is 275mm (common on boats and perfectly ok, but not good in a house) then the step can only be 90mm deep according to your formula. 90mm obviously isn't right. For a boat the two numbers need to be about 600mm and 800mm. IMHO

 

[jfm]

I have drawn the upper step " IN " the transom, to indicate that this was the deck level, so that this is not a real step, I was not wrong, my drawing was not clear.....at least in my mind it was correct.

Ah, ok, I see your point. My mistake!

my droodle is more or less the same as your drawing ,look at the grey line in my drawing, it stops just underneath the upper outside step.

Agreed. Yes, looking again at your picture, it is indeed the same design. Sorry that I didn't notice this. It would benefit from recessing the top step as discussed above

I can see that you like the perfect look of the alalunga idea, sketch below, and I have to agree with you that would be perfect. As for the cost/benefit of the extra say €15k cost, only you can decide!

 

[vas]

I think your formula is a (non naval) architectural rule, for houses and public buildings, but it doesn't apply to boats.

If the riser is 275mm (common on boats and perfectly ok, but not good in a house) then the step can only be 90mm deep according to your formula. 90mm obviously isn't right. For a boat the two numbers need to be about 600mm and 800mm. IMHO

Jfm,

you are right, but I think I'm also right in that in section the part of the step outside (i.e. not under) the one above it will be around 90mm in these risers. The bit that is under can be another 100mm or so, but the uncovered one counts. Also IMHO
There is also the issue of assisted stepping up (ie. holding the bollard or whatever you call that...) vs unassisted.
And finally at what ratio you stop call it a staircase and call it a ladder, like in my fb access which I'd not call it anything but a nicely designed ladder.

V.

 

[MapisM]

Yet another thought

Bart,
also after all the latest (indeed valuable) suggestions, I can't help thinking that - structural considerations aside - all of them would spoil the simple, straightforward beauty of BA stern section.
Which obviously wasn't built for moulded stairs, and nothing can change this fact.
You know, being disappointed by the final result after throwing a lot of money at the project is a risk I'd rather avoid, in your boots.
So, I still think that if she were my boat I wouldn't touch her, even assuming money no object.

That said, one alternative for facilitating the access to/from the platform (and also the water) is the following.
Also this would be rather expensive, because you should throw away the whole existing passerelle, but it also has the advantage of the sliding section which allows you to regulate the passerelle length - something you can't do with the existing one.

And maybe (though I'm not 100% sure), the previous passerelle with foldable steps could also be built with the hydraulic rigid stanchions (much better than the usual ones with a rope) which you can see in the following pic, either on both sides or just one. Btw, I'd rather have them just on stbd side, in your case.
Very convenient when returning onboard with diving equipment, and much better (= safer and lighter) than any hi/low platform.

 

[jfm]

Nice idea MM. I think however, though Bart will know, that BA does not have enough length in the engine room to take such a long passerelle, when retracted inside the boat. The current passerelle folds to reduce its length by 50%

 

[MapisM]

Actually, also the passerelle in the first pic above is in two sections, and reduces to 50% or so length when retracted.
Btw, the sliding 2nd section is partially extracted in the pic. In fact, if you look at the three steps on top you can see that there's empry space behind them.

Yep, the 2nd passerelle instead can not be reduced, but that was just to show the stanchions.

Anyway, the builder can customise pretty much everything, based on the client needs.

 

[jfm]

Ah, ok, thanks. I think they make the handrails solid by making them telescopic, for the slide in-out passerelles, if you want solid instead of rope

 

[MapisM]

Correct. In fact, I've seen those solid handrails also with sliding sections passerelle, as you say with telescopic tubes.

The reason why I said that I'm not sure about whether the foldable steps AND the solid handrails can be fitted together on the same passerelle is that they're both hydraulic, and if they share the same mechanism/circuit, maybe you can order either one or the other, but not both.
Easy to check anyway, if B would be interested.

 

[BartW]

before I post my comments on previous posts, here are some pictures:

I have drilled some holes in this border, and draw some dots.
The black dots mean: there is solid wood underneath
The open O’s mean: there is only a few mm plywood underneath

Conclusion: there is just a small wooden beam, connecting the 2 bulwark sides, to hold the plywood cover, and the SS step plate.
But no large structural beam for stability of the boat.


Then under the cockpit floor:

There is a large trunk under the rear cockpit floor,
This is about 60cm deep, and 60cm wide, full beam from passerel to the Port side of the boat
Its made from 12mm plywood, covered with GRP on the inside
Here are pictures taken in that trunk, upwards to the spot where the floor is fixed on the wall.
There are 8cm beams for supporting the floor, but nothing more structural

This is below this trunk,
In the picture you can see the fixing screws of the platform
And 2 times 3 screws, fixing the flanges from the ladder.

The first step from our newly designed GRP stair would come where now is the bottom of that trunk, approx 5cm above that vertical GRP Beam.

That trunk has to disappear completely, so we will have a lot more space in the util room.

 

[BartW]

you're opting for 4 risers instead of the now 5. Care to check the height please (or just tell us the exact height from platform teak to aft deck teak),

the hight from the platform till the teak deck is 100cm,
so 4 steps of 25cm is perfectly doable I think. (<275mm)

remember the 5the riser now is to go OVER that border

 

[jfm]

so 4 steps of 25cm is perfectly doable I think. (<275mm)

4x250mm will be very nice

 

[BartW]

I don't know why they kept that thick section, but the most likely is as Bart said - to deal with the hinge angle. The "bulwark" here is sloping inwards, on the inside, and so to make the door not hit the deck it would be necessary to have an offset hinge pin on the inside which would be ugly and a serious toe stubber. I agree that a "trick2 could be done to cure this in a better wqay, like a door opening out pantograph style but Canados seemed to prefer simple inward hinges and seemed not to be bothered with any trick (sadly!), so I think they just (slightly lazily) designed it this way.

you have to know that this model, the C70s, is the succesor of the C70, which was still produced until 2 years before BA was made.
main 2 differences were:
- reverse angled stern shape
- C70 was wooden hull, C70's is GRP hull BUT the bulwark on the C70's, like BA is still wood, inside aswell as ouside.

I believe that this style of transom doors was typical for wooden hulls.
This was Canados first day's with GRP hulls, so no fancy nor clever modern designs yet.

all IMHO

 

[BartW]

Bart, my comment would be to question to costs of the stairway mouldings. This would be a one-off pattern, with no other sensible use. In order for the stairway to be sympathetic to the craftsmanship in the rest of your boat would imply quite an expensive mould, in addition to all the local detailing work to ensure that the new stairway fits seamlessly with the transom. You then have potential issues with gelcoat colouring. Matching to BA after many summers UV attacks will be challenging. Even if you can match now, the new moulding and transom changes are likely to deteriorate at a different pace from the original material, so in a couple of years time, the changes could be very apparant.

In conclusion, JFM's stairway would not require a mould, and would need minimal changes to the current transom, giving you fewer long term issues with colouring too.

Yes I agree that the cost of this GRP stair (17k) is substantial and for many mates on here not worth the benefit.
But when you know that it is less then our mooring cost from the last 5 months, and that our first season on BA we used >20.000liter diesel (since june) puts this cost more in to perspective.
And just for the affirmation, its my own money earned with honest and hard work.

about the collour matching,
this bulwark is made from wood, inside aswell as outside, so this is painted, and already now the collours don't match,
as we have to redo the painting of this upper part (not urgent) , it might be a good occasion to paint the complete hull with polyester paint, as the old GRP also looks dull,
polishing might be good also,...
but again this is not urgent.

thanks for taking time to post your comments !

 

[BartW]

Bart,
also after all the latest suggestions, .... all of them would spoil the simple, straightforward beauty of BA stern section.
Which obviously wasn't built for moulded stairs, and nothing can change this fact.
You know, being disappointed by the final result after throwing a lot of money at the project is a risk I'd rather avoid, in your boots.

well what can I say, yes you're right there is a potential danger that this will spoil the straight lines of the stern section, I'm very aware of that, and could show examples of modifs on boats that look horrible,
but we may not forget that this was the first model that Canados produced with GRP hull, and from then, all the following models had GRP stairs,
so I believe that this modif won't look strange

moreover, its not like a oldtimer car, where we want 100% the orriginal,
this Canados design is nice, but not Iconic,
there are small things that could be or have been improved compared with the original.

but yes I agree that I should question and think about this modif very carefully, and thats what I'm doing right now.

I used to draw in Autocad but that was 10y ago, so forgot about it,
now its the right moment to learn Google scetchup (fully 3D) I believe,
again one more tasc to do

Bart,
That said, one alternative for facilitating the access to/from the platform (and also the water) is the following.
Also this would be rather expensive, because you should throw away the whole existing passerelle, but it also has the advantage of the sliding section which allows you to regulate the passerelle length - something you can't do with the existing one.

And maybe (though I'm not 100% sure), the previous passerelle with foldable steps could also be built with the hydraulic rigid stanchions (much better than the usual ones with a rope) which you can see in the following pic, either on both sides or just one. Btw, I'd rather have them just on stbd side, in your case.
Very convenient when returning onboard with diving equipment, and much better (= safer and lighter) than any hi/low platform.

I like your idea's, especially that thinking out of the box,
but before replacing that existing passerelle, there must be some very good reasons.
Last summer we had a few issues with it, but I was able to sort this out, now I know that this passerelle is not state of the art technology, but it is simple and solidly build. and replacing that is a hellofajob, not mentioning the cost of another modern one;

moreover,
I don't like it that I don't have the good stairs when moored.
especially when there will be a transomdoor on the platform, and me or a crew member wants to go to the util room with stuff while moored ...


the GRP stairs, the transom door, and the "extra" Hi lo platform, are very usefull additions , that will increase the comfort and pleasure on board I think.
all IMHO.

 

[MapisM]

I don't like it that I don't have the good stairs when moored.
especially when there will be a transomdoor on the platform, and me or a crew member wants to go to the util room with stuff while moored...

Yep, I did consider that the steps embedded in the passerelle mean that you must either use the passerelle OR the stair.
I didn't see that as a big deal though, but each to their own!

Re. the hydraulic platform, I can only suggest to have an accurate estimate of the total additional weight (mechanisms, larger platform, transom strenghtening which might be necessary).
On that basis, I'd ballast the stern and go for a seatrial, before confirming the job.
It could be difficult to secure the ballast on the swim platform, but that's critical for the simulation, because the farther the weight is from the CoG, the greater the effect on planing attitude.

 

[jfm]

Bart, really basic question, if you add say 1.5m of new up/down swim platform, will your existing passerelle be long enough?

 

[BartW]

Re. the hydraulic platform, I can only suggest to have an accurate estimate of the total additional weight (mechanisms, larger platform, transom strenghtening which might be necessary).
On that basis, I'd ballast the stern and go for a seatrial, before confirming the job.
It could be difficult to secure the ballast on the swim platform, but that's critical for the simulation, because the farther the weight is from the CoG, the greater the effect on planing attitude.

yes I have been thinking about that,
we could make a support on the platform, and fix XX number of dive tanks on it, and some lead bloks, ...
I really want to try that, but then I need assistance from somebody who can accurately test / verify the behaviour of the boat .... ?

 

[BartW]

Bart, really basic question, if you add say 1.5m of new up/down swim platform, will your existing passerelle be long enough?

yes it is, I'm sure.
even more, but don't know exactly how much,
1.5m is perfect I think,
and with rails for the tender studs, to shift the tender forward when the platform is up.

the existing platform is 75cm

look at the pic in post #5