Bruntons Varifold and Rope Stripper - Not Compatible

We read a really scary article in Yachting Monthly this month where quite a few of the boats taking part in the Biscay Triangle Rally got something caught on their propellers or rudder. Dick Durham opens the article nicely by stating:
"It was dirty weather that worried the 11 skippers crossing the bay of Biscay with Blue Water Rally's annual 'Triangle' cruise. But it was rubbish filled seas that caused the problems"

This inspired me to reinvestigate the possibility of fitting a rope stripper. I think the recognised market leader in this space is Ambassador. Yachting Monthly also gave them the thumbs up in the same issue. Handily they produced this (somewhat amateurish) video of the tests:


Apparently Ambassador Marine make the only cutter that works with a saildrive. They've got a really dated looking video explaining their offering here:


I called them and ordered one for £470. The man at the end of the phone used language like "yeah.... I think it should be ok with your propellor". This didn't instill me with confidence, so I called Bruntons and asked.

I was told that the prop needs to have mounting holes drilled into the metal and that this was possible with the Autoprop (their premium offering), but the Varifold had some sort of plastic component that meant that it was incompatible. So that was the end of that. There was no problem cancelling the order with Ambassador though.

We then spent the weekend worrying about whether to upgrade to the Autoprop and buy the rope stripper. When Bruntons came back to us we were told that we could return our (unfitted) Varifold and exchange it:

---

Dear Mr Collins,

Thanks for your enquiry to upgrade, the costs are as follows, this includes taking your 2 blade back into stock.

APS-416mm 3 blade £1317.01

APS –H20-430mm 2 blade Autoprop £788.01

Additional charge for rope cutter modification £145.00 for 2 or 3 blade

regards

Bruntons

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So the cost would have been:

Rope cutter	£470.00
Upgrade prop	£788.01
Modification to accomodate cutter	£145.00
Total	£1403.01

The big question is: "Is this worth it?"
I suppose if one of us had to go over the side in cold, big seas with a knife to hack away at a rope, we'd probably pay that much there an then to avoid that unpleasant & potentially deadly task. We had to do this in Bequia on our first charter, except it was, warm, clear water with no swell to speak of and really the only actual risk was the ferry terminal a cable's length away and other boats in the anchorage. I don't want to have to repeat this again in a hurry. Doing it in less tropical climes would be much horrible.

So that means the big question is really: "Is this going to happen to me?"
I'm told that there's less chance of this happening to saildrive boats because the prop is much deeper in the water, but it's certainly not impossible.

It's worth noting that the vast majority of fouled props are self inflicted (as ours was), so it's possible that good boating practice (such as tidying mooring lines away quickly) can dramatically lower the chances of being stricken.

After a weekend of agonising, we decided not to bother as we'd made the decision to choose the prop that we did on the grounds of sailing performance & an autoprop and stripper will add extra drag, plus the pretty significant extra expense.

Fingers crossed.

A first glimpse of water

I've been watching the Bullando Marina webcam nervously after an engineer at Brohall Marin (who are based there) told me a couple of weeks ago that there was still 20cm of ice in the marina. Finally the ice now looks paper thin and even a few patches of water - which is good because we're planning on putting the boat in the water in 10 days!

Propeller Decisions

One of the points raised in the survey was the need for a new propeller - the existing one is badly pitted and I'm told causes some nasty vibrations. As with anything in the marine industry - the choices are endless. However they can be grouped into the following three categories: Fixed, Folding & Feathering.

Type	Pros	Cons
Fixed	Cheap, Simple	Highest relative drag
Folding	Lowest drag	Traditionally poor in reverse & less power than feathering
Feathering	Best motoring performance both ahead and astern. Reduced "prop walk".	Higher drag than a feathering prop.

The original specification had a Volvo Penta folding prop. It's safe to say that there have been quite a few advances in this field in the 22 years since the boat was built. The blades of the prop are flat like the tip of a screwdriver, which has an impact on the motoring performance. Premium feathering props solve this problem by offering variable pitch based on RPM and some can even reverse the blades when going astern. The only downside of feathering propellers is that they produce significantly more drag than a folding prop. I've known of a racing skipper fit a feathering prop to replace his folding prop and get a better handicap, so it clearly makes a difference.

In terms of vendors there are a lot of choices:

KiwiProp

This is a feathering prop made in New Zealand (as if the name wasn't enough of a clue). What makes it a little different from the rest is that the blades are plastic. They supply a spare blade as a part of the package, the intention being that these are sacrificial in the event of an underwater impact. It is pitch adjustable by the user with an Allen key. Whilst it doesn't offer variable pitch in the strictest sense, there is some clever trickery when reversing that makes the blades snap into "optimum" angle of attack.

Bruntons

Bruntons is a UK company and is definitely one of the leaders in the field. The offer the Varifold - a range of 2, 3 & 4 blade folding props and the Autoprop which is a premium feathering prop with variable pitch and a number of other special features. They also offer fixed props and at the boat show were exhibiting standard feathering propellers, but these are not mentioned on the website.

At the London Boat show, Bruntons had a tank with an Autoprop running in it. Every five seconds it would switch between ahead and astern propulsion. Seeing the blades feathering and unfurling for the new direction was really fluid, almost organic in motion. The Autoprop is a truly impressive machine, with only one significant disadvantage - Cost. We were quoted a boat show price of about £1700 for the saildrive model, which is about 70% more than a branded feathering propeller. That being said - I'm absolutely convinced that if I had a motor sailor or planned on lots of motoring I think the cost would be more than justified.

Gori

Gori is a Danish company who specialise in low drag folding propellers. Like Bruntons, they have their own magic that sets them apart from the rest. Their folding props are able to unfold differently for ahead and astern as well as providing an "Overdrive" feature which is a different blade profile for fair weather motor-sailing.

They also sell ultra low drag racing propellers, which would be tempting, except I suspect that these are built with sailing performance as being the primary factor, and motoring distant second. If I had a race boat they would definitely be on the list. Speaking of which, Swan mainly use Gori propellers. I feel that they let themselves down in terms of customer interaction. I mailed them for a quote and absolutely zero response two months later. Additionally there was no sign of them at the London boat show (although they do plan to be at Southampton). For the above reasons I can't tell you what these beauties cost.

Volvo Penta These guys represent the safe choice if you're already equipped with a Volvo engine and saildrive. They are obviously a Swedish company. They offer standard 3 & 4 blade folding propellers and represent the vanilla end of the market. I'd suggest that these are probably more appropriate for cruising boats in that they don't offer a 2 blade option for reduced drag that would appeal to the cruiser/racer market. Expect to pay around £700-£800 for a 3 blade folder.

Max-Prop

Offering a range of feathering props, which seem to be the Oyster Yachts weapon of choice. Some positive user reports of these across the Internet.

Flexofold

Apparently the Managing Director of Gori left and created this range of propellers, which is claimed to be superior. They also appear to have good links with various boat builders. Interestingly there are relatively few user anecdotes across the net good or bad. After meeting Bruntons at the boat show we decided that we liked them as a brand: Friendly guys on the stand, British company, great products. Our main fear of going for a folding prop was the much fabled poor performance when going astern, but the Bruntons guys explained that with modern folders such as their Varifold, this issue is greatly reduced. This is due to a twisted blade profile - making it more similar to a fixed prop in terms of motoring characteristics. We decided that we valued the low drag of a folder more than the better motoring of a feathering or Autoprop. The same logic applied to 2 blade vs.. 3 blade, so we settled on a 2 blade Varifold. At £740 it was also nearly £1000 cheaper than the Autoprop.

It arrived in the post yesterday. My first comment is that I'd have liked to see a little better packaging. The bottom of the box was sagging from the immense weight of its cargo. When I opened the box it's clearly an exceptionally well engineered product and effortlessly glides between motoring and sailing configuration.

I’ll post more when we fit and use it.