Blue Angel (Canados 70s) Rebuild thread

[Deleted User YDKXO]

I have the impression that BA planes flatter then Britt. Olesinski hulls, 3...5deg (just a guess)

The video looks like a fairly standard planing attitude to me. I would say about 5deg. If it was 1 deg, it would be undetectable to the eye. I think the Iphone has an app to measure angle btw!

not much to experiment,
with trim flaps raised, she planes fairly flat, even at slow speed.
there is no method to make her more bow high
in case you missed it, look at this video, this was with trimflaps raised.

Actually I didn't explain myself very well. What I meant was that if BA runs at its most efficient speed with its tabs partially down, then you have the option to take tab off to raise the bow further. The British boats I have owned seemed to run at their most efficient speed with zero tabs so there is no option to raise the bow further. IMHO there seems to be a greater range of trim adjustability at least with the Italian boats I've owned

 

[BartW]

The video looks like a fairly standard planing attitude to me.

I' ve seen pictures on here that show much different (bow high), but again I'm no specialist

Actually I didn't explain myself very well. What I meant was that if BA runs at its most efficient speed with its tabs partially down,

I didn' explain myself well, I mean that I hardly ever use trim on BA, and when I use trim for opitimum efficientcy, the trim level is so small that it is hardly noticeable, so it wouldn't make much difference in a big following sea,
On BA the usable trim range is very small.

 

[jfm]

With a tiny bit of trimflaps down, I get a tiny bit more RPM, it is experience from the previous captain.

What exactly do you mean BartW? In a cruise, adjusting the flaps will not affect RPM because the governors will make sure they don't. You must be saying that if you run the boat at full throttle (ie with the governors doing nothing) and you lower the flaps, the rpm rises. Are you really satying that? How many rpm? Or is it just a report from the previous captain?

I am trying to reconcile it with the laws of physics becuase I cannot really imagine how in a general on a 70er planing mobo lowering the flaps can improve mpg/litres per mile

 

[BartW]

What exactly do you mean BartW? In a cruise, adjusting the flaps will not affect RPM because the governors will make sure they don't.

You're right, what i mean is the speed of the boat increases a tiny bit,
(looking at the speed figure on the gps)
Nothing to do with RPM,
Indeed the governors wont allow,
I was wrong,

And agree with you that more trim on such a Boat wouldn't normally improve efficiency,
But this was an observation/sugestion from the previous captain, which i seemed to acheeve in a few occasions, flat see, ...
At constant and stable speed, Giving a tiny bit of trim increased the speed .5 knot
But the difference was very small, almost neglectible, so perhaps just coincidence, waves, wind, ....

Already beginning of the summer i noticed that one trim cylinder leaks a lot of oil, sinds then i havent used trim anymore.
Some more testing to be done next season after a liftout and repair of that oil hose fitting.

 

[rafiki_]

no apoligies needed Rafiki, I only felt constructive advice.
My answer to your post was also supposed to be an answer to all other mates who questioned the spending.
But a warning every now and then doesn't harm, as I tend to get used to useless spendings



yes I'm curious to see that,
we had 3 custom made canopies on previous boats ( 21ft, 25ft, 29ft) from the same supplier (man in the pic)
so have some experience now, and I'm interested how others make them.

Bart, I hope to see the new canopy early in the new year. Will post some pics when she is all kitted up.

 

[BartW]

here are the détailed drawings for the GRP steps

I believe the size of the steps is OK like this,
unless some new idea / advice comes along, this is what we are going for

current situation

new situation

 

[mainshiptom]

I love this tread not only design issues and decsions are taking place it is backed up by some cool wakeboarding of a mega yacht !!

Now you can see why I love this site !!

Keep it up Guys


Tom (Boatless)

 

[jfm]

Perfect imho.

250mm riser is fine. And your 260/300mm dims are good

You have a little triangle to fill in with GRP either side of the new gate - the bit I referred to as "jambs" above iirc

Also, scuse pedantry, in order to "feel" right among engineers, this stuff has to be done in mm not cm Bart

 

[jfm]

Bart you have to make a philosophical decision about the angle of the whole stair case relative to the transom curve. I think you need to align/make square to the boat's centreline, not the transom tangent/radius. Get my drift? You'll have to move the exisiting s/s handrails therefore

 

[BartW]

You have a little triangle to fill in with GRP either side of the new gate - the bit I referred to as "jambs" above iirc

my idea was, in stead of a 10...20mm thick GRP triangle
I want to place a 80mm wide beam, on both sides of the gate door,
so from the cockpit you will see a 80mm wide post on each side of the door.

The good thing is that this beam slopes to 0 mm thickness on top, and doesn't stick out from under the Gunwale capping,

all difficlut to explain, but
this would look nice and solid from the inside imo

 

[MapisM]

Looks nice! Just a thought: if as I suppose you will have the steps made in teak, I would definitely put a steel plate under the first, to strenghten it.
No matter how thick the teak will be, it's bound to crack sooner or later if it has to bear hundreds of kg (dynamic load) on its border.

 

[BartW]

Bart you have to make a philosophical decision about the angle of the whole stair case relative to the transom curve. I think you need to align/make square to the boat's centreline, not the transom tangent/radius. Get my drift? You'll have to move the exisiting s/s handrails therefore

Yes I know,

I think I want to make the steps in a Trapezium shape; smaller on portside.
and on conckpit side, the steps are square to the center line,
and on the outside, in line with the tangent transom shape
(get it ? )
the dimensions in the drawings are taken in the middle of the GRP steps,
so they are not the same on the extremes

don't get your advice on the handrails,
they will have to move cause the gate will be wider,
perhaps I put only one, instead of both sides
cfr pictures with examples posted here above

 

[BartW]

I would definitely put a steel plate under the first, to strenghten it.
No matter how thick the teak will be, it's bound to crack sooner or later if it has to bear hundreds of kg (dynamic load) on its border.

yes agree,
alternative is to make the GRP mould starting from the platform, but I think it is nicer as it is (adding a ssteel plate)

 

[MapisM]

don't get your advice on the handrails,
they will have to move cause the gate will be wider,
perhaps I put only one, instead of both sides

Bad idea imho. I'd rather climb the previous ladder with two handrails, than the new stair with just one.
Particularly in a drift dive scenario, where the boat can be rolling due to some waves.

 

[jfm]

I think I want to make the steps in a Trapezium shape; smaller on portside.
and on conckpit side, the steps are square to the center line,
and on the outside, in line with the tangent transom shape
(get it ? )

Exactly!

don't get your advice on the handrails,
they will have to move cause the gate will be wider,
perhaps I put only one, instead of both sides
cfr pictures with examples posted here above

Even if the new steps were the same width as the old ladder, the bottom of the exisiting handrails, if you were to keep them, would have to move 50mm to starboard. Reason is that the current steps follow the conical shape of the transom surface, so they tilt to port at the bottom, compared with top. your new steps will not do that, for the reasons stated above

So you have to move the rails, but that is no big deal. Anyway, your current handrails are not made perfectly. At the bottom, one is closer to the swim platform than the other, by 15mm or so, (tsk canados!) so you need to modify them a bit anyway

All good!

 

[BartW]

Bad idea imho. I'd rather climb the previous ladder with two handrails, than the new stair with just one.
Particularly in a drift dive scenario, where the boat can be rolling due to some waves.

correctomundo !

 

[BartW]

Anyway, your current handrails are not made perfectly. At the bottom, one is closer to the swim platform than the other, by 15mm or so, (tsk canados!) so you need to modify them a bit anyway

what an eye for detail
got your remark about the position of the handrail,
thanks !

 

[jfm]

No matter how thick the teak will be, it's bound to crack sooner or later if it has to bear hundreds of kg (dynamic load) on its border.

I would make them in 2x 15mm marine ply laminated with epoxy glue (to avoid the cost of an 8x4 foot 30mm sheet!) and then do the step surface in black caulked teak 8mm thick, and do the edges in 38mm x 12mm solid teak nosing, like picure below. Solid teak blocks would look daft imho. Based on the stength/stiffness of 30mm of plywood, the s/s plate isn't absolutely necessary if Bart wished to avoid it, but it would be a nice touch and would make general fixing of the step better. I would certainly use the s/s here, through bolted thru the bottom GRP tread, to avoid visible fixings in the teak step

 

[jfm]

correctomundo !

You have spending too long with mother tongue english speakers, and young ones at that (which includes me of course)
You'll have a cockney accent next!

 

[jfm]

my idea was, in stead of a 10...20mm thick GRP triangle
I want to place a 80mm wide beam, on both sides of the gate door,
so from the cockpit you will see a 80mm wide post on each side of the door.

The good thing is that this beam slopes to 0 mm thickness on top, and doesn't stick out from under the Gunwale capping,

all difficlut to explain, but
this would look nice and solid from the inside imo

Agree 100%. 80mm post each side would look nice and solid/ship feel. Nice job!