Paravanes boom position?

[Larry M]

...Wouldn't it be safer to deploy the poles first, then the vanes ? That is what I had in mind and planned to do.

I also plan to make the vanes from ply and round off all the edges, and paint them with epoxy. I was also thinking of maybe having a simple guide rail for the retrieval cable, that flips out when needed. The guide could be running from in front of the sailwinch and then pivot a foot or so to the side of the gunwale. That way I think it could be possible to reel the vanes in almost all the way to the top, without touching the hullsides too much. Larrys Hobo has the winches installed higher up on the mast poles, so I think they do almost all of the lifting...

The fish are deployed with the poles out. When we leave the dock, the poles are down. It’s real quick and easy to then deploy the fish.

Ours are made from 3/4” marina plywood. If I bump the side of the boat, no scratches or dings. We get about 5-10 years out of each one and then I replace the plywood. The plywood does get soft depending on how much they’ve been in the water. We use them at anchor for flipper stoppers and sometimes they soak for a few weeks at a time. I’ve met several comercial fisherman who have replaced the plywood with HDPE or similar.

We use the winches to bring the vertical line the fish hang from, to get them next to the boat, then I grab the wire/chain and manually lift the fish out of the water. I just down sized our fish from the larger size, about 300 square inches, to the next size, about 210 square inches. We’re not running the distances or large open water stretches any more and these should be easier to handle. The new ones were $145/each plus shipping. They come with an aluminum paint and I repainted them with a one part polyurethane.

 

[JDCAVE]

Ooooo! Stainless chain Larry!

 

[Cold-smoked]

We use the winches to bring the vertical line the fish hang from, to get them next to the boat, then I grab the wire/chain and manually lift the fish out of the water. I just down sized our fish from the larger size, about 300 square inches, to the next size, about 210 square inches. We’re not running the distances or large open water stretches any more and these should be easier to handle. The new ones were $145/each plus shipping. They come with an aluminum paint and I repainted them with a one part polyurethane.

Thanks, Larry. I thought the winches did most of the lifting too for you. I will try to find a simple way to make the winches hoist the fish up to the gunwale/rails, thus making it more attractive to use them even for short day trips.

 

[Searios]

About the rudder: I don't think the articulated rudder will help much when going astern...It's very easy to stall these rudders...I have one, absolutely truly fantastic when there's prop wash over it- but a bit difficult when going astern...

 

[JDCAVE]

My A-Frame, poles, and guywires are basically the same as Larry's. However, other than the chain to the paravanes, I have removed all the accessory lines. Deploying, I drop the poles, slow the boat down to dead slow and drop the fish in the water. No winches. Retrieving, I stop the boat and raise the poles almost all the way to the boat, one pole at a time. I then use a pike pole to pull the chain to the boat and carefully lift the paravane from the water, taking care that it does not strike the hull. I then repeat the process with the other pole. Note that it is nearly impossible to pull the poles if there is any "way" at all on the paravanes, so the boat needs to be stopped. This sounds like a lot of work, but I can pull the poles and retrieve the paravanes in 5 minutes. Same for deploying if the poles are up.

Several points: You need to anticipate conditions. It's not a fun or safe process to do this in rough conditions. At the very least the poles are down. Putting the fish in the water can be done in rougher seas, but I don't like being on the top deck dropping the poles if the boat is rolling.

Jim

 

[Cold-smoked]

About the rudder: I don't think the articulated rudder will help much when going astern...It's very easy to stall these rudders...I have one, absolutely truly fantastic when there's prop wash over it- but a bit difficult when going astern...

I am sure you are right, but I must do something with mine to get better overall rudder authority. I could probably achieve a lot just by elongating it a bit and weld on some steel angle bars to help direct the wash.

 

[Cold-smoked]

Several points: You need to anticipate conditions. It's not a fun or safe process to do this in rough conditions. At the very least the poles are down. Putting the fish in the water can be done in rougher seas, but I don't like being on the top deck dropping the poles if the boat is rolling.

Jim

Thanks, Jim. I get your point, and of course I want my system to be as safe and simple as possible.

 

[Cold-smoked]

Just my crude idea. Lots of cables & hand winching to be done, but little heavy manual lifting involved. And the winches should provide smooth deployment & retrieval of the poles. Retrieval line would have to be stored near/above poles to keep it dry while under way. Quite messy, so I'd probably end up removing it all shortly after installation :lol:

 

[Wxx3]

Jim
With only one boom out, the turning moment (rotational force) would be calculated as the moment f x d where f = drag of one paravane and d = the horizontal distance from the centerline of the mast to the tip of the boom (not the length of the boom unless it is completely horizontal). It is the distance from the centerline that provides the multiplier in the calculation. The boat is not rotating about the forward connection point, it is rotating about the mast.

I can see why you think it does ‘pull’ the bow around. It seems logical that it would. The calculation of force on the rigging is separate issue and would be used to correctly size the rigging for the loads applied. You would also think the forward stay would reduce the torque on the mast by alleviating the backward pull of the paravanes and it does do that to the extent of the load is applied to the forward stay. But this does not apply to the theoretical calculation of where the load is considered to affect the vessel.

By the way, all the calculations applied to the boat that make up both horizontal and longitudinal stability are theoretical positions. But they seem to have been working out just fine for the last hundred years or so. Guys working in finite math have refined and model tested the heck out of the calcs and would laugh out loud at how crudely I have described the math. But in the end the finite calculations would be within 0.5% of mine. So I am okay with that. [emoji106]


Cold Smoked:
Nice boat. If it worked well as a trawler since the 1940’s, is there an issue now that makes you think you need a different type of rudder? Is it underperforming in any sort of meaningful way? If not, I don’t understand the urge to spend significant cash. If you think that the steering characteristics are going to change substantially by running paravanes from the forward mast, I would strongly suggest a sea trial first with the paravane installed forward to see how it handles. I suspect you will find the steering is still good. No need to change either mast position or rudder unless you are doing it for aesthetic reasons. One advantage of having the mast forward rather than over the wheelhouse is that the entire system is in view from the helm while I operation. I agree with trying to maintain the original character of the boat. I think that is a lovely idea..

I think I am saying the same as McGillicuddy. The bow is NOT pulled sideways. I frequently run with only one paravane in the water to save a little resistance and there is no effect on steering.
The KK42 rotates around the base of the mast. That's why the paravane position is slightly forward of the mast, about 2 feet. Whuich I think is the LCG of the boat.

I believe that James Krogen designed them there to equalize the force on the forward and aft mast stays. I added two additional mast stays that are also just forward of the mast.

As Larry on Hobo stated, that 2 lbs/sq in looks good as I have estimated the force on the line to the end of the pole at about 2,000 lbs.
I bought a crane scale, so I hope to be able to measure some real number next year on each of the stays.

I've been in all sorts of seas and my autopilot has never had a problem. It simply can't tell the difference. It's a ComNav and while I do adjust it a bit depending on conditions, it takes the worst conditions well. Otherwise I could not have crossed the ocean last year.

I will say that the paravanes are least effective with large mixed following seas with 7 to 9 sec periods. But then nothing can help that and they still reduce roll 50% under those conditions. In a beam sea, roll is reduced 90%.


I have written a number of posts on my blog about the paravanes.

Email me if you have specific questions.

 

[Wxx3]

My A-Frame, poles, and guywires are basically the same as Larry's. However, other than the chain to the paravanes, I have removed all the accessory lines. Deploying, I drop the poles, slow the boat down to dead slow and drop the fish in the water. No winches. Retrieving, I stop the boat and raise the poles almost all the way to the boat, one pole at a time. I then use a pike pole to pull the chain to the boat and carefully lift the paravane from the water, taking care that it does not strike the hull. I then repeat the process with the other pole. Note that it is nearly impossible to pull the poles if there is any "way" at all on the paravanes, so the boat needs to be stopped. This sounds like a lot of work, but I can pull the poles and retrieve the paravanes in 5 minutes. Same for deploying if the poles are up.

Several points: You need to anticipate conditions. It's not a fun or safe process to do this in rough conditions. At the very least the poles are down. Putting the fish in the water can be done in rougher seas, but I don't like being on the top deck dropping the poles if the boat is rolling.

Jim

Yeah, what he said.

I always lower the poles after leaving harbor to avoid going on a rolling top deck. Though it was a PIA in the Caribbean since they thought I was fishing.

My rig is much less rig than Larry's and Jim's. My rigger who installed them convinced me less was better.
SO I have no "A" frame, but lines from the pole to the top of the mast, with stress posts in the mast to transfer some force to the other pole.

I love the system. I was also designed with me in mind, in that the failure of the rigging that Jim described, i managed to do. But my only loss was a $300 Al pole, as designed.

I retrieve them much the same, but when alone or in a hurry I have been know to deploy them at 6 knots. After the first time, i learned to make sure i threw the bird straight down, otherwise it skims across the water for quite an exciting time.
I've told myself never to do that again, but Never Say Never and I've done it a half dozen times.
But I will stop. I promise.
I will also re-rig my lines this summer.

 

[Cold-smoked]

I frequently run with only one paravane in the water to save a little resistance and there is no effect on steering.
Email me if you have specific questions.

Thanks for the input, but I believe you said on earlier threads/posts that your boat veered off by around 5 degrees with only one fish in the water ? That is actually what I would and will expect.

 

[Searios]

I'm thinking of making a similar retrieval system, but have been told that the extra wire (to pull in the SS ring) will create drag and therefore might change the angle of the fish (turning it towards the boat)...that said, there are several systems out there that has similar retrieval systems which works..

 

[Searios]

I guess, that its a trial an error thing...try different ropes (maybe even thin Dynema rope) - try different positions of the ring etc...if nothing works, then its back to the old method of grabbing the wire with a grab hook and lift the fish in manually...

 

[Searios]

If you decide on winches then make sure you get self the tailing....

 

[Cold-smoked]

Yes, but my idea was to store the retrieval line so that it will not touch the water while under way.
Meaning tightly around/above the poles - so that it doesn't slide down into the water. The ring has no position, other than being loose around the cable/rope going to the vane.

 

[Cold-smoked]

If you decide on winches then make sure you get self the tailing....

Thinking about it, sailwinches are probably overkill for my needs - but they sure look good & are resistant to seawater.

These regular hand winches are more than enough for my needs, but they are bulky. Red one has two ratios, 5:1 and 12:1. Stainless steel one 4:1

 

[Wxx3]

Thanks for the input, but I believe you said on earlier threads/posts that your boat veered off by around 5 degrees with only one fish in the water ? That is actually what I would and will expect.

Well, if I said it it must be true.

I probably should have said that once that deflection took place, it was constant, not varying and therefore no issue.

Thanks for the nudge

 

[Wxx3]

I guess, that its a trial an error thing...try different ropes (maybe even thin Dynema rope) - try different positions of the ring etc...if nothing works, then its back to the old method of grabbing the wire with a grab hook and lift the fish in manually...

I don't retrieve the birds until the poles are vertical. At that point, I simply pull the line in.
It's not very complicated. I have used a winch with a small 1/4" amsteel line that paralleled he main lines. That worked well. Though the connections for the winch were not stout enough.
So I ended up doing it my hand for the last 6 months again.

Either way, alone, I can retrieve both birds in 3 min once the poles are vertical. I've done both from underway to stopped and retrieved in 5 min.

 

[Xsbank]

The cable that suspends the fish in the water can be replaced by a purchase (block and tackle) so there are no extra lines in the water and the fish can be raised without a winch. Unless you use a winch with a large enough drum to keep the line on permanently. Sailboat winches are (fairly) cheap used, I bought a very nice black-anodized 2-speed for $100 including the handle. Not a perfect finish but for my boat?

I bought some very nice (but very spendy) Japanese stainless blocks for my rigging. Took a lot of searching to find mine.

 

[Xsbank]

Sorry, photo didn't load:

 

[Larry M]

I don't retrieve the birds until the poles are vertical. At that point, I simply pull the line in.
It's not very complicated. I have used a winch with a small 1/4" amsteel line that paralleled he main lines. That worked well. Though the connections for the winch were not stout enough.
So I ended up doing it my hand for the last 6 months again.

Either way, alone, I can retrieve both birds in 3 min once the poles are vertical. I've done both from underway to stopped and retrieved in 5 min.

I tried that once. I had a pole about half way in when we rolled so the pole was past vertical toward the boat and slammed into its holder. Then we rolled the other way and the fish pulled the pole out. We just leave the poles out from the time we leave the harbor till we get back into one.

Here's a picture with the paravanes deployed. You can see the block at the A-frame and on the pole that we use when we want to pull the poles in. With a 4 to 1 mechanical advantage, they come in pretty easy. The winch is used to pull the line that the fish hang on to the side of the boat.

These are good threads since paravane installations are all one offs for the most part.

 

[McGillicuddy]

Larry, that is a nice looking boat. Appears very ship-shape and seaworthy.

 

[Wxx3]

I tried that once. I had a pole about half way in when we rolled so the pole was past vertical toward the boat and slammed into its holder. Then we rolled the other way and the fish pulled the pole out. We just leave the poles out from the time we leave the harbor till we get back into one.

Here's a picture with the paravanes deployed. You can see the block at the A-frame and on the pole that we use when we want to pull the poles in. With a 4 to 1 mechanical advantage, they come in pretty easy. The winch is used to pull the line that the fish hang on to the side of the boat.

These are good threads since paravane installations are all one offs for the most part.

I did like your system of retrieval.
Since our rigging was different, it turned out we put spin-lock things on the mast for each of the lines that controls the poles. That makes it easy for me to receive the pole to vertical (in time with the roll). The spin lock stops the pole from flopping back.

The most expensive part of the system was the Japanese? pulleys at the top of the mast, connected thru the mast with a compression post. Each pulley was $500.

 

[Cold-smoked]

I plan to only use blocks for the retrieval of the poles, one on each side of the mast - both lines sharing one winch. I will use simple and cheap ones, as I see this as a bit of an experiment.

A simple ss ring at the end of the retrieval line for the vanes should work well with cable, rope and chain too - depending on the shape and size. A tiny hook on top of the poles will keep the line clear of the water, and the other end can be secured to a cleat or going back to the winch.

Got all the pipes and steel bars today, if weather stays good - the build will begin on monday.

 

[Cruising Sea Venture]

Paravane Placement

Great discussion.

We are having a new superstructure and paravane's installed on our 54" Cheoy Lee LRT this winter. The work is being done at the Port Townsend Shipwrights Co-Op in Port Townsend, WA, with the Tim Nolan Marine Design doing all the naval architect work.

We choose them because they were by far the most experienced in paravane systems in the Northwest that we could find.

We discussed the idea that the most efficent placement of the poles was 28% of the Water Line Length from the stern. On our boat, it was just too far back for the new superstructure and the lines of the boat. We ended up being about 40% from the stern. Based on the architect's analysis, the difference was not significant. He only indicated they might be a little less effective being further forward. Since we decided to overbuild the system, so the poles could be longer - 26' long, to maximize the stability, it's didn't seem to be a big issue.

In the end it seemed while 28% was ideal - a boat is a series of compromises, and this one did not seem to be a deal breaker.

If you want, you can see the refit and design drawings on our youtube channel - Cruising Sea Venture.

Best of luck on your project.

Jim Addington
M/V Sea Venture

 

[Wxx3]

Thanks Jim
Let's plan on crossing paths next year.

Richard on Dauntless

 

[Cold-smoked]

Decisions, decisions...

Poles are mostly done, I have to sand and wire brush a little. Then decide the poles lengths before I cut them and drill the bolt holes for the gunwale mounts. The pipes came in lengths of 6 meter/20 feet, but I think I will cut them down to 16 or 18 ft. I have to consider the boats appearance when the poles rest, so the shorter the better...

And the more I think about it, the more I realize that the poles should be behind cg. The idea of having the poles in front of the cg concerns me now, the bow getting pulled downwards by the vanes when going over wavetops. At best it's a bit uncomfortable and the boat just gets a bit wetter, but possibly it also could be dangerous. This boat behaves really well and comfortable in following seas, btw.

So now I want to make a push and pull A-frame over the front of the wheel house, which is around 1/3 lwl from the stern. This area is perfect strength-wise, with easy access to beefy frames and beams just underneath the deck. But it sure will change the boats appearance, and that may be acceptable. Perhaps I can cover and wrap the frame-pipes with fishnets and tiny buoys, hmm ? Any ideas or suggestions are welcome, thanks.

And thanks, Jim/Sea Venture. I really like your boat and I watched several of your nice videos on YT. You sure cruise around lovely places up there, it's quite similar to here with the fiords, narrows, nice halibut and more. I'm at 69° north, btw.

 

[Cruising Sea Venture]

Paravane Design

Your project looks like it's coming along great. We know even with a naval architect doing the design work / calculations there were a lot of decisions to make.

Here are two of our design drawings and a photo of the superstructure under construction. We added the crows nest, mostly just for fun which added a lot to the superstructure. We are also using it to mount 8 antenna's along with the radars as well.

69 degrees sure a long ways north - but what a beautiful setting for your cruising adventures.

Jim
M/V Sea Venture
youtube/CruisingSeaVenture

 

[Cold-smoked]

Thanks Jim, those plans and pic look great - and I'm certain that your paravanes will work very well with the poles being in that position. Will you dare to climb up to the lookout while at sea ? The nest sure looks cool

 

[Simi 60]

I bought some very nice (but very spendy) Japanese stainless blocks for my rigging. Took a lot of searching to find mine.

These 304 s/s which we have on the davits for lifting a 700lb dinghy may be of use.
Plenty of different suppliers and cheap

https://m.ebay.com.au/itm/STAINLESS...hash=item3f88eedd1c:m:mWqcCThtTfQ8P7guLrslsEw