Bavaria Ocean 40 bimini

[Markus]

Trying here to make plans for various jobs around the boat, as there's not much more to do than plan in this situation... One thing that we need is a bimini. I have been contemplating various designs but having difficulty in deciding. I imagine at least some people in here would have an opinion...

I suppose the options fall into the following two subcategories (pictures taken from googling):

1. Narrow version, mounting on cockpit railing (see attachments bimini_narrow_1 & bimini_narrow_2)
+easy to fold out of the way (I prefer to fold the bimini sometimes if for example maneuvering in a tight port)
-relatively narrow

2. Wide version (see attachment bimini_wide)
+good protection from sun
+keeps the cockpit clear of bimini tubing
-impedes access to side decks/stern
-limited clearance for mainsheet when running of

All comments welcome - thanks!

[Yngmar]

I think this is an unsolved problem on centre cockpits with mainsheet aft of the helmsman. I've looked around a lot and seen solutions ranging from awkward over bad to downright terrible.

We have the wide one and it's an absolute pain in the ass to get past it with the slimelines in hand when med-mooring. Otherwise it's only marginally in the way. The mainsheet rubs on it when the sail is at certain angles. At winds over 25 knots it begins to flutter and make noise.

I'm probably going to switch to the narrow design because ours annoys me so much. You will also want extensions for the sides which you can deploy when not underway and/or when the sun angle is low, and one at the back that you can also use when underway, because wide or narrow, the sun often gets to the helmsman as the Bimini has to end rather abruptly where the mainsheet begins. Just like in that one photo you attached - the poor guy is roasting while the crew is in the shade.

And then ideally I would like it to have attachments so it can become a fully enclosed cockpit tent in winter, so that we don't have to carry two sets of canvas and tubing!

Unfortunately all of this costs thousands and I'm not sure I feel qualified to sew my own.

[geoff]

i would go narrow . I used to co-own a Beneteau  411 which we sailed to the Med from UK  . It had a wide bimini which was good for shade and a pain in the ass for everything else . Winds over about 25kt made it shake ,but the worst was when we got into the Med  when the standard stern to mooring with daughter chains and a ring on the quay the lack of free access to the stern quarters became a real
 pain . Geoff

[Lazy Pelican]

We have a B39 aft cockpit, with a wide Bimini. We wouldn’t consider going narrow- unless the sun is directly overhead you’ll spend all your time in direct sun.
Remember once in the Med you probably spend less than 10% of the time underway & some of that will be motoring!
We have friends with a centre cockpit / narrow Bimini and frankly it’s useless.

Whatever you decide you will need detachable side and back screens - our zip on.

[Markus]

Excellent comments, keep them coming...

@Yngmar: If you fold up the bimini before mooring, is it still pain in the ass with the mooring lines, etc? I managed to find a picture of your setup from your blog and to me it looks like it would not bother too much with the mooring activities as long as it's folded up but maybe I am missing something...?

@geoff: I fully agree that with Beneteau 411, as with many other after cockpit models, wide bimini really makes access to stern quarters (lines, cleats) very difficult. But with Ocean 40 as with other center cockpit models, even the wide bimini leaves still ample space at the aft deck so I do not think this is a problem.

I suppose the minimum wind speed for fluttering is just a function of canvas area and the stiffness of the frame. For Ocean 40, a narrow bimini top would be approx. 2 m wide where as a wide one would be around 3.5 m wide and longer, so the area is easily at least double...

I have seen one Ocean 40 with bimini tracks mounted outside the cockpit but not on the side-decks (see the attached picture), maybe we can call this an intermediate version. The frame would lower in front of the wind screen, which seems nice as there's nothing left up when it's down. The downside must be that it cannot be very robust with just one rigid anchoring point per side and needs several webbing straps... It just occurred to me looking at the picture that you could actually use the existing genoa track for the bimini as well!

Maybe the best way to go would be to make an arc for the mainsheet traveller and integrate a bimini to it. This would result in no problems with the main sheet and a very sturdy structure for the bimini. But not a small project... 

[Markus]

Did some sketching for the "intermediate width" bimini. Mounting the bimini on deck, as opposed to cockpit coaming give at least an additional 500 mm of width, which could make a big difference in terms of shading. Having the mounting points inboard on deck would also keep the side-decks uncluttered. The aft support struts would be on the cockpit coaming (red circles in the attached picture).

Any thoughts?

[Yngmar]

Be careful with the winches - you'll want ample swing room for the winch handle and so you can get an upper body above the winch for proper winching with room for elbows. Also, personally I wouldn't put the supports on the deck, as that's pretty much a guaranteed broken toe for someone. Somewhere on the coaming outside the teak trim is probably best. Supports can flare out from there for a wider top if needed.

Ours is in the way when mooring even when folded, although less than when deployed. This is because the supports turn inward and you sort of have to squeeze past and support yourself with one hand on a winch to not fall over. Would actually be better if the supports flared out along the line of the stanchions and then came back in further up.

Also, the supports are cleverly right across the opening of the stanchion gates on both sides...

Oh, and when folded it still interferes with the mainsheet, unless you drop it behind the mainsheet, which means undoing that (we have a large caliber soft shackle on the bottom for that, but it can't be done under sail).

I've seen one that had the Bimini attached on top of the stanchion gates, which is much better in terms of room, but makes for a horribly wobbly setup.

It really is a tricky problem to solve!

[Markus]

Yes, agreed, I am also a bit concerned about the winches with my plan.  In principle if facing outboard 30 cm around the winch is enough but facing forward I think at least about 70 cm is required aft of the winch and 30 cm forward of the winch for some elbow room. The clearance between aft and fore bimini tube at winch handle height is about 85 cm so not quite enough for forward-facing winching. I think a slight modifications could give a bit more elbow-room (see attachments). In any case I think the situation with winches is better with the wider bimini than with the supports inboard the winches, unless you go for the design in my original post, which then blocks the side entrances to cockpit...

If the supports were on deck immediately aft of the genoa track, I do not think it really increases the risk of broken toes as the track-end needs to be avoided in any case.

I think in general some inward flare of the supports would be beneficial as this significantly solidifies the structure: if the supports are vertical or outward flaring, the only thing resisting lateral movement of the whole bimini is the bending stiffness of the piping whereas some inward flare also transfers part of the lateral forces on deck.

Well, it's good that I have one more job ongoing so I will have to let this sink in a bit before I start ordering the piping... 

[Salty]

Yes, agreed, I am also a bit concerned about the winches with my plan.  In principle if facing outboard 30 cm around the winch is enough but facing forward I think at least about 70 cm is required aft of the winch and 30 cm forward of the winch for some elbow room.
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Well, it's good that I have one more job ongoing so I will have to let this sink in a bit before I start ordering the piping... 

You have clearly put a lot of thought into this project, and with lockdown over here because of the Covid 19 pandemic I can’t go to my boat to check the length of my winch handles, but I would think that 30cm clearance is not enough to stop you from taking the skin off your knuckles on each full rotation of the handle. I have three winch handles onboard, and while two are of fairly similar short lengths and might just allow sufficient clearance at 30cm, my favourite winch handle I’m sure would demand more space to ensure no injury, particularly when handling Genoa sheets which often require a bit of extra effort to get the sail set where you want it. If money was in plentiful supply, then electric winches would ease the situation, but where do you start to draw the line........?

[Markus]

You have clearly put a lot of thought into this project, and with lockdown over here because of the Covid 19 pandemic I can’t go to my boat to check the length of my winch handles, but I would think that 30cm clearance is not enough to stop you from taking the skin off your knuckles on each full rotation of the handle.
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If money was in plentiful supply, then electric winches would ease the situation, but where do you start to draw the line........?

Actually, I have just thought about this a few evenings now and got some ideas from your collective input and constructive criticism which has been very useful. But I did some preliminary thinking while roasting without a bimini last summer...  You might well be right regarding the dimensions: due to covid-outbreak I have also been to the boat last time in November and the dimensions were based on "winching" over a coffee cup on my desk...  Maybe the supports need to be vertical to allow for more space around the winches. The aft struts can be fairly diagonal so that should help a lot with the stiffness of the frame.

I think I will need to make a proper 3D model of the frame and see how it looks like...

And I definitely draw a line well before electric winches! 

[Symphony]

Winch handles are 200 or 250mm (actually good old imperial 8" and 10").

[Symphony]

www.tecsew.com has a number of photos of biminis they have made, including several centre cockpit boats. Might give you some ideas

[Jan Faldt Bentsen]

#markus. I am the owner of the intermediate Bimini you posted a picture of. I had it build in Portimao and are attaching picture and measures, drawing to assist you. We are very fond of the size, as it does not conflict with port manoeuvres. It is stable. And the size gives a good shadow. The with is 2,6 m and length 3,6 m. Please feel free to contact me if you have any questions.

[Markus]

#markus. I am the owner of the intermediate Bimini you posted a picture of. I had it build in Portimao and are attaching picture and measures, drawing to assist you. We are very fond of the size, as it does not conflict with port manoeuvres. It is stable. And the size gives a good shadow. The with is 2,6 m and length 3,6 m. Please feel free to contact me if you have any questions.

Jan, huge thanks for the excellent input and drawing! I am glad to find someone there with the "intermediate version" who's happy with it. It clearly seemed like the best choice for me but I have been trying to think if there's something fundamentally wrong with my thinking, as most seem to have either a wide or narrow version...

You mentioned 3.6 m length in the message but the drawing shows 3.1 m in the middle and 2.9 m at the side - I assume the drawing must be correct. Could you also let me know what is the minimum distance between the aft end of your bimini and the mainsheet? Does the bimini interfere with the mainsheet when running off wind or is the curvature at the aft end of the bimini enough for the sheet to clear it??

By looking at your photo, it seems to me the bimini you have can be folded forward on deck if you first move it aft on the tracks, is that correct? I definitely want something that can be easily folded away as I am quite tall and get annoyed if my view is compromised when for example maneuvering in a tight marina.

[Jan Faldt Bentsen]

Markus, youre right use the drawing for size. As I see it, we are next to each other on Aegina. I will arrive on 16/5. Perhaps we meet.
The mainsheet can interfere with the Bimini, when sailing broad reach/dead downwind. Under theese wind directions and if you have the boom mainsheet out, it will conflict with the aft. ribbon fastening the Bimini. But they are easy to open and slack.
The Bimini can be folded in front of windscreen and also behind the traveler, but then it is neccesary to unmount the mainsheet. It can be moved on the track as you mention. With a litlle experience you will be able to manouvre in/out of marinas as you have the side deck free. We are 2 persons sailing La Tifre for years and find no problem. Offcourse, it takes your view ie sailing through Corinth canal, but every Bimini will do so.
I normally mount the Bimini wery close to the mainsheet, 10 cm. As it is designed with the same curve as the mainsheet/boom. Unless situations mentioned above.

[Markus]

Markus, youre right use the drawing for size. As I see it, we are next to each other on Aegina. I will arrive on 16/5. Perhaps we meet.
The mainsheet can interfere with the Bimini, when sailing broad reach/dead downwind. Under theese wind directions and if you have the boom mainsheet out, it will conflict with the aft. ribbon fastening the Bimini. But they are easy to open and slack.
The Bimini can be folded in front of windscreen and also behind the traveler, but then it is neccesary to unmount the mainsheet. It can be moved on the track as you mention. With a litlle experience you will be able to manouvre in/out of marinas as you have the side deck free. We are 2 persons sailing La Tifre for years and find no problem. Offcourse, it takes your view ie sailing through Corinth canal, but every Bimini will do so.
I normally mount the Bimini wery close to the mainsheet, 10 cm. As it is designed with the same curve as the mainsheet/boom. Unless situations mentioned above.

I did not comprehend it really was your boat in the picture although that's what you wrote - small world! I will send you an email a bit later...   

[jwleblanc]

The narrow (1st picture) example you show in the original post is a picture of my boat. Yes, you do get a little toasty seated at the helm, it can be a little tricky getting in and out of the cockpit but I rarely take the bimini down unless expecting heavy winds. The frame does get in the way of the long handled winches but if you look closely at the picture the previous owner had upgraded to electric winches. I was opposed to them at first but they have made it much easier to sail short handed.

We are in the Northeast US and take advantage of the full enclosure in the fall or just in heavy rains. it makes a big difference in keeping the boat dry with extra coverage.