Wheelhouses, Biminis and Bridges

The Question

Rather than bloat a travel posting, for this important aspect of our cruising, and one that took a lot of planning and considerable cost, we decided to make this a standalone article. A question that has always been on our mind – how will we get Catharina Elisabeth under the bridge at Capestang? Here we are, pondering the issue in 2013, a year we even bought Neo Vita. So, we have been working to answer this problem for the last 12 years, and now, in 2025, we’ll see if we have the correct answer.

What’s the problem?

Air Draft

Air draft is a term we use to describe how high a feature of a boat (generally the wheelhouse roof) is above the water level. It’s especially important with respect to bridges, as if the air draft of a wheelhouse is greater than the clearance of a bridge, very bad things happen if you try to pass through. Right from the start of choosing Neo Vita (as she was named then), we knew that the air draft of the wheelhouse and the bimini would be a problem at some of the low bridges in France, particularly on the Canal du Midi and the Canal du Nivernais. Neo Vita’s air draft was stated to be 3.1 m. The raw value for the maximum clearance for the bridge at Capestang (the oft-quoted “most restrictive bridge” on the French canal system) is 3.3 m. However, there is much more nuance to that figure. Many bridges are arched:

So, while the clearance at the peak is, for Capestang, 3.3 m (comfortably more than Neo Vita’s air draft), her wheelhouse is 3.0 m wide. So, as the clearance at that width is only 2.95 m, we would either be jammed under the bridge or do severe damage the wheelhouse as we passed through. Worse, the bimini was almost exactly the same height as the wheelhouse, and it extends the full width of the deck – 4.0 m wide. At that point, clearance is only 2.7 m (see below for what happens when a bimini hits a bridge). These facts have been an issue for both of us for the ten-plus years as we slowly drew closer to the bridge at Capestang. What to do?

Wheelhouse

Our first modification was to trim the height of the flange on the front of Catharina’s wheelhouse, which we arranged during the winter of 2018-2019 in Simon Evans’ yard.

The navigation light fixtures were also modified to allow for easy, temporary removal of the housings. At the end of this, and perhaps with a bit of extra steel from the overplating, Catharina’s wheelhouse in 2025 was 2.9 m above the water at the centre and slightly less at the edge. So, a comfortable (according to me) or unnerving (according to Lisette) 5 cm or more of theoretical clearance.

Bimini

This was much more involved.

The original mounting of the bimini had it firmly and permanently attached to the stern side of the railings and the rear of the wheelhouse roof. Again, in Simon’s yard, during the 2018-19 winter, Simon and his welder Mark modified the fixed poles on the port and starboard railings to be hinged on the top and bottom and removed the centre stern pole altogether. They then modified the port and starboard fixings to the wheelhouse so that the bimini attachments slotted into posts (the middle fixing was removed), held in place by a cotter pin that could be removed to allow the detachment of the front of the bimini. When that was released, the rear poles could pivot backwards, and the entire bimini could fold back and down to the level of the railings.

Once lowered, the bimini was still 4 m wide, but now at only 2.5 m above the water, so easily able to pass narrow arched bridges.

It looked like this dismounted:

We tested this in 2019 on the Nivernais and managed to destroy the new system after clipping a partially raised bridge. Simon and Mark repaired it over the winter of 2019-20 in time for COVID.

The problem with this system was that while lowering the bimini was relatively easy (although it tended to crash down – scuffing Lisette’s painted rails in the process), raising it was very difficult. It required me to crawl right under the bimini, squat and push it upwards, and then both of us to push and drag it forward to reconnect to the wheelhouse posts.

By 2025, we felt that we had to find a better way to lower and, particularly, raise the bimini. We started in Auxonne with some assistance from a local and added a pulley at the rear of the bimini, a u-bolt at the centre of the wheelhouse roof and then found that if we prevented the bimini from dropping flush with the railings (putting some boxes on the top of the stern deck box), so the back of it was already raised, we could pull it up and forward more easily.

It was pretty difficult still. The breakthrough came from my brother Martin during his visit in July 2025. First, we added another pulley at the wheelhouse u-bolt, thus halving the effort needed to raise the bimini. The pulley he recommended also had a ‘v’ in the casing so that if the free end of the rope was pulled back at an angle, it would lock into position.

That then allowed us to precisely control how far down the rear of the bimini dropped and a simple way to pull it up to a sufficient height, lock the rope again, and then push it back to fix onto the wheelhouse. This was the magic that made lowering and raising the bimini a practical exercise. Kudos to Marty. Unfortunately, we don’t have really good photos to illustrate all this, but here are a couple to give you an idea.

We had a couple of practice runs in port and this worked well. Next, trialed it while actually cruising. The process we’ve developed is that first we remove the navigation lights (we leave them off as we don’t cruise at night and the only tunnel on the Midi-Garonne is only 165 m long and perfectly straight) then:

1. Find a straight stretch of canal, slow down, and Lisette takes over the helm.
2. Ian removes the split pins from the wheelhouse mountings.
3. Lisette leaves the wheel, and we take either side of the bimini, lift it up and out of the tube mounts and gently push it sternwards until the leading edge of the bimini is resting on the rails
4. Ian takes the rope, Lisette takes the helm.
5. Ian releases the rope slowly, controlling the lowering or the rear edge of the bimini until it reaches a spot marked on the rope that gives the optimum raised position and snaps the rope into the locked position.
6. Ian takes over the helm.

It seems to work.

Raising is roughly the reverse:

1. Slow and swap the helm.
2. Ian pulls the rope to raise the trailing edge of the bimini then locks the rope.
3. Lisette leaves the helm and both push the bimini leading edge up and forward into contact with the wheelhouse mountings.
4. Lisette returns to the helm while Ian secures the bimini on the wheehouse mountings with the split-pins.
5. Ian takes the helm.

Low Bridges

It’s notoriously difficult to eyeball a bridge to determine if we can clear it. One tool is that the forestay is the same height as the wheelhouse. If the forestay won’t go under, it’s time to slam on reverse.

Width is more just a judgement. However, to help, we have use of a spreadsheet (from the DBA website) on which the curves of the low bridges on the Midi are depicted and on which we can superimpose our wheelhouse and bimini.

Here’s what it looks like if we pretend we are going to keep the bimini up.

The width in red at the top represents the bimini. The shape below doesn’t represesnt the profile of the wheelhouse, it’s an artifact as the spreadsheed can’t plot a narrower profile (see below for what the wheelhouse alone profile looks like). You can see that the edge of the bimini is greater or equal to the clearance for Capestang (in green), Paraza (in violet) and Marengo (in orange). Actually, the Paraza dimensions are wrong, it has much better clearance. But with the bimini up, two bridges and, hence, the Midi would be denied to us. So for those bridges, and anything else that we are tentative about, the bimini goes down.

Here’s what it looks like if we have the bimini down:

From this, we see that the edges of the wheelhouse are well clear, as are the tops of the railings. I just have to make sure we are centred and don’t wander as Catharina passes through.

The remaining issue is that we aren’t keen on lowering the bimini or having it down in high winds. Once it is freed from the wheelhouse, it is pretty much just a sail, and if the wind catches it while lowering or if it comes from astern, it may rip the bimini off the articulated poles.

Was it all worth it? Will it work? See the next blog.