Sea brake on a canoe stern boat

[GILow]

Hello Cruisers,

While I waited impatiently for some decent wind to test my staysail setup (see thread on beating home alone, and oh so slow), I got into the boat today and cleaned up the sail locker.

In my tidying I found the sea brake and realised I had not addressed a question that has bothered me since I bought the boat.

Being a canoe stern boat (Swanson 42), all else being equal, should I run the sea brake from the bow or the stern? (Should the need ever arise, I certainly hope not!)

Is there an accepted wisdom on this one?

(For the record, it is a Burke GP30 Seabrake, seems to be in good condition and it came with 100m of 24mm Woven Polyester and 50m of 12mm Polyprop line. There is also what appears to be some kind of bridle to fit it to the boat, probably off the mooring line cleats.)


Matt

[GordMay]

The SeaBrake is intended to be towed approximately 3 boat lengths astern.

➥ http://www.seabrake.com/

➥ http://www.seabrake.com/pdfFiles/Sea...uctionCard.pdf

[GILow]

Thanks Gord May, I've got that one (actually, I have the original black and white paper brochure that came with the sea brake too! How old fashioned!), but I was particularly interested to see if anyone was aware of any issues about canoe stern boats towing sea brakes. I didn't make that clear in my post.

There's a thread started by Crimea Cruiser titled "Storm Tactics for Double Enders" which I missed before I posted (too keen!) which seems to address much of what was worrying me.

Matt

[Talbot]

One of the reasons why large parachutes are needed when you want to attach to the bow, is the need to effectively stop motion through the water. If the parachute is not big enough, the boat will start to gather sternway. This will put significant strain on your rudder, and can lead to breakage. It will also lead to the boat being at the wrong angle to the next wave.

The seabrake, will slow you down sufficient for most conditions, but will need the boat to be steered in the correct direction.

Do not underestimate the forces on a drougue. You should basically be just about able to lift the boat on the fittings that you use.

[Snowpetrel]

Paul welded some strong chainplates for his drogue and JSD on his canoe sterned yacht. See some details and a good story of it's use here . This has got to be an ideal solution for a series drogue.

But for the seabrake it is nice to be able to adjust the length. I have always run mine out through a strong and well rounded fairlead on the starboard quarter (in the northern hemisphere I would reverse the sides and run it out to port) when it is at the right length I attach a bridle line to the port side with a prussik loop or rolling hitch to act as a bridle and center the lead. This way it misses the windvane. I run both lines back to the biggest cockpit winches and then to solid cleats. Makes it easy to recover and adjust.

If you don't have a windvane their is nothing to stop you running straight out the center of the stern, and onto a mooring cleat. As long as they are all good and solid. The main thing is good chafe protection. The bridle does help keep the boat running true, but I don't think it's essential on a canoe stern.

100 meters might just be a enough length.. I would like more for a real blow. I remember having a plastic squid (much like a seabrake) out on about 60 meters of nylon climbing rope once and the whole drogue was leaping out of the face of the wave behind us as we started to surf, chain and all. The next time I had to use one we had about 150 meters of warp out (18mm poly) and it worked much better.

You definitely want a bit of decent bit of chain in the line as well, no harm in going for more than they say, and never use nylon rope on one because the stretch causes very bad things to happen. The 12mm stuff is way to light to be of any use for this setup.

Test your setup under motor sometime. And make sure to seize any shackles... My folks lost their original seabrake due to the supplied shackle being a nice allen key one that couldn't be seized properly, and the Loctite didn't work.

All the best and let us know what you come up with.

[GILow]

Well, there are a pair of pretty solid looking mooring cleats either side of the stern, but I will get below decks and see how they are mounted. Sounds like they have to very well mounted indeed.

The bridle arrangement has rubber hose around the ropes in a number of places, which I assume is to stop the chafing, that should tell me if I have set it up as intended.

I like the idea of testing the whole setup with engine, I will certainly try that on the next trip out, unless the much awaited wind finally reappears... then I have to test staysail setups instead.

Matt

[Kettlewell]

The Sea Brake wouldn't have enough drag to hold your bow up into the wind and you would end up sideways to the seas, which is not what you want in bad conditions. There are some tales of folks using Sea Brakes in the Drag Device Data Base book if you can find one.

[GILow]

Originally Posted by Kettlewell

The Sea Brake wouldn't have enough drag to hold your bow up into the wind and you would end up sideways to the seas, which is not what you want in bad conditions. There are some tales of folks using Sea Brakes in the Drag Device Data Base book if you can find one.

Ahhh.... right... off the stern it is then!

On the upside, recent correspondence with the chap who set the boat up so well suggests that I might see him much later this year, so provided I don't do anything silly before he arrives, he'll be able to provide some pointers on all this gear. After 21 years living aboard I figure he must have sorted the safety aspects out pretty well!

[banjoship]

Matthew,
I have no knowledge or experience with the SeaBrake, and cannot comment on it. However, a few general comments may help

A few years ago, I researched what might be appropriate for my Swanson 42. There is extensive literature and web sites on the topic of drag devices. And much debate on forums such as this, with many opinions, like anchor debates. I reached the conclusion that a drag device from the stern is the most appropriate for a canoe stern, heavyweight, full keel cruiser such as the s42. The high stern and centre cockpit of the s42 are important factors..

I bought a Jordan Series Drogue from Series Drogue in Melbourne. The proprietor, Bryan Glover, sails a Swanson 28, and reckons the series drogue is ideal for the cruising family of swansons, though he might be a bit biased.

For the series drogue, the attachment points for the bridle are crucial. In terms of spacing, and strength. Working from notes from Jordan and from Glover, it seems in a worst case scenario, that the individual arms of the bridle on a Swanson 42 could be subject to a load of 9 tonnes. Deck cleats and mainsheet winches are not up to that sort of load. The recommendation is for purpose built plates on the hull, fastened similarily to chain plates, but running horizontally.

I don't know if your SeaBrake would generate the same sort of load as a series drogue.

In Banjo's case I fashioned the attachment points as follows. The gunwales are about 38mm thick, solid glass; there are scuppers just fore and aft of the chainplates; so I fashioned a bridle to go round all that (actually, Glover made it up for me, out of 27mm nylon braid). I consulted extensively on this attachment point, including the builder of Banjo, and there is no doubt it is strong enough. However, I am not happy with it...too much sweep over the stern. But it also gives me a strong point if I ever need to be towed. At some stage I will put plates on, as per recommendation.

I have trialled the series drogue, deploying it in 25knots, and retrieving it the next day in 12-15 knots. Even in that light wind, retrieval was hard. Don't under estimate the forces at work.

I would counsel against deploying your SeaBrake from the bow, especially as I get the feeling that it is meant to slow you down, rather than stop the boat completely. There is extensive discussion on this in the literature.

While my faith is in the series drogue, I also have recently bought a Para-Tech sea anchor (made in Melbourne). It is meant to be deployed from the bow and to stop the boat completely. No experience with it yet, only bought it because it was so cheap (deceased estate).

Don't know if this helps you any. BTW, I would suspect that the 12mm poly line is for retrieval??

I would strongly suggest getting onto SeaBrake for instructions, load factors, etc.

Lee

[GILow]

Thanks Lee, will do as you suggest on all points.

I am optimistic that the original owner will have specced the rear cleats to take the load, but I won't assume anything.

Yes, I also suspect the 12mm line is for retrieval, that would be very much his style. But I will have to double check the lengths, as at 50m it would not be long enough, it should really be around 10m longer than the main line.

Matt

[Kettlewell]

Not directly relevant to the Sea Brake, but I have used a small parachute as a drogue offshore on a 32-foot catamaran in estimated Force 9-10 conditions, with occasional heavy breaking seas. Mine was a Buord parachute, on 400 feet of 1/2" nylon rode. I used our ordinary stern cleats for attachment and in my estimation the loads were not excessive. In fact, I think most of the time they were basically equivalent to anchoring in similar conditions. When a heavy breaker comes along there is a surge load, but having a long length of nylon acts as a shock absorber and helps to gradually accept the load along the length of the line so that the boat does not experience a shock load. I had no equipment to measure the load, but 1/2" nylon (breaking strain around 6000 lbs.) held it, and was apparently undamaged in the process. I could physically manhandle the rode at times during the storm, if I timed my exertions to coincide with lulls. I think a long length of shock absorbing nylon is important in these offshore sea anchor and drogue systems, and I like a bridle to spread out the load over multiple attachment points and to keep the boat more aligned with the wind and seas.

[Snowpetrel]

The seabrake (or any small single element drogue) is a very different concept from the Series drogue, and the loads are considerably less. With a seabrake out in a real good blow you would probably be making about about 5-6 knots. Whereas the Series drogue will reduce your speed to 1-3 knots with much higher loads.

The seabrake is a downwind control device, stopping surfing and reducing broaching. a helmsman or windvane is still probably needed to keep the boat on course and safe.

See here for some more info on them. I like having the both aboard, The seabrake for when I want some speed, and in strong gales. And the series drogue for the ultimate storm or so I can rest below and think that a swanson 42 will perform very well with both with her bouyant rounded stern and centre cockpit.

I have never had any real problems retrieving a seabrake type drogue. They shouldn't need trip lines. Just pull them in with a cockpit winch, timing the pull with the slack from waves motion. Don't use a stretchy nylon line on a single element seabrake, it doesn't need it and the stretch can allow the boat to start surfing, and then break out the drogue.

Very interested to here how any trials go. If you get the seabrake ready you are bound to get to much wind to test it easily, so thats one way to get some wind to try the staysail...

All the best