h170 boom height

[heliBartek]

There's been some talk in the past of experimenting with 170's boom mounting point. Few guys mentioned thinking of lowering it by a foot or so to see how the overall performance would be affected. No doubt boats' leaning tendency would be greatly reduced.

Just wondering if anyone has actually tried it and what the outcome was.

Cheers

 

[Brian M H23]

Just talking...

The center of efforit is about 13 feet up. Lowering it to 12 would be ~ 7% decrease in heeling moment. a 7% decrease in wind speed means in 15 knots, it will heel like it's in 14 knots of wind. I can't imagine it going any faster, the amount of power is still the same, but it should heel over as if the wind was 1 knot weaker for every 15 knots of wind.

 

[heliBartek]

Not to mention the added benefit of greater over-lap between jib and main thus improving main's laminar air flow. In effect boat becomes more of a full sloop instead of fractional sloop.
I've always felt that 170's designers went little too far with the boom height. In my short time owning the 170 I've learnt to reef the main early on especially when single-handing otherwise anything over 10-11 kts and she becomes a real bear to handle due to heavy leaning.
The whole issue of boom lowering is an interesting concept and I was hoping someone would have reported back on the full effects of it by now, especially seeing that it was originally brought up on this forum back in 04'

cheers

 

[txjim]

Of course, one of the benefits of the boom height is headroom. Less acrobatics during tacks/jibes.

Is there a way to objectively measure improved handling? Heeling angle under identical wind conditions may be possible but anything else is pretty subjective.

 

[heliBartek]

Come on people !! - I know somebody out there tried this mod so lets have some valuable feed back.

Another added benefit of lowering the main by about 12" would be a possibility of installing a simple, adjustable back-stay thus really increasing the ability to trim this boat perfectly for just about any conditions.

That's what so great about forums like this one - people come up with all kinds of clever mods that show these guys at Hunter Marine what could have been.

Cheers

 

[Kevin13729]

Come on people !! - I know somebody out there tried this mod so lets have some valuable feed back.

Another added benefit of lowering the main by about 12" would be a possibility of installing a simple, adjustable back-stay thus really increasing the ability to trim this boat perfectly for just about any conditions.

That's what so great about forums like this one - people come up with all kinds of clever mods that show these guys at Hunter Marine what could have been.

Cheers

I would not be brave enough to cut 12" off the bottom of my mast unless it was damaged or something. I suppose the stays could either be shortened or mounted higher?

 

[heliBartek]

Actually all I did is lower the attachment point for the boom. So far I managed to lower it 14" with out any adverse effect on anything else.

I have not tried it out yet on the water but I figure there will be a noticable difference in the heeling angle. Hunter went a little crazy with that boom height.

Be few more months before I can test my new setup but when I do I will report back on it.

 

[BlueRunner]

​

I have not tried it out yet on the water but I figure there will be a noticable difference in the heeling angle. Hunter went a little crazy with that boom height.

Be few more months before I can test my new setup but when I do I will report back on it.

PLEASE do give us a report. I'm especially interested in whether it makes "coming about" a bit spastic moving side to side and the effect of forward visibility. I do love having the mast at the "stock" height with the ease of moving from side to side.

Call me a chicken, but I don't sail in moderate winds (which at this time I can't define in terms of speed). When I did my sea trial, we really should have postponed it. All we had flying was the jib and I felt we were going over more than once.

What I really want to do is wait for a nice day later this spring and then pull the boat over manually to see if I can "right" the boat singlehanded.

 

[David Hall22685]

If you have "foamed" the mast then righting the boat is a snap! It seemed like it wanted to right itself and be on the move again. I LOVE my 170. All it takes is a little Devcon and it will follow you anywhere!

 

[BlueRunner]

Mast foaming technique...

Last fall I saw a thread here about masts "foaming", but now I can't find it with the search function.

I assume in the best situation, the entire mast would be foamed, but if only a partial foaming is done, then at least the top part should be foamed. Because of a problem with my mast head halyard wheels described elsewhere on this forum, I'll be removing the head soon. Since the top will be open, this would seem to be a great time to at least foam the top.

I'm wondering how many "noodles" can be stuffed down the mast before they get hung up on restrictions to sliding down the "chute?" Also, is there a recommended size to these foam noodles? I think I read elsewhere that 2" noodles should be used. Is that the right size for this job?

Any response to these questions or a link to the previous posts on noodling would be greatly appreciated.

 

[heliBartek]

Hey Bladerunner check out the tread under the subject of Mounting a wind vane & mast float on 146. I posted a short description at the begining of what I did on my h170's mast.

I don't really understand why people keep stuffing all sorts of would-be flotation devices down their masts. The easiest thing to do is to simply seal the top of the mast with with some expanding foam or silicone or any other water-proof sealant. Shape a small dam out of small piece of styrofoam (or something similar) shove it few inches down the mast and pile on all the sealant in front of it. Let it dry and your're done.

If you're really serious you can also use silicone to seal all the rivets that attach various things to the mast. No need to go crazy, just a little dab of sealant on all the heads.

Once I finished with all the mast water-proofing - to test it I simply laid the mast out on my lawn, elevated the foot of it about 5 feet in the air, and filled it water via the opening in the bottom using a garden hose.

To be perfectly honest I don't think I would have ever taken this boat out on the water without doing this mod first.

Hope this helps. And here's a link to more useful stuff

http://hunter.sailboatowners.com/index.php?option=com_kb&Itemid=267&cat_id=11&page=model&mn=170

Cheers

 

[Kevin13729]

If you have "foamed" the mast then righting the boat is a snap! It seemed like it wanted to right itself and be on the move again. I LOVE my 170. All it takes is a little Devcon and it will follow you anywhere!

Which "Devcon" product works best on repairing your Hunter 170? I've seen about 4-5 different products with that brand name but not sure which to use. Just bought my 170 last month and have a couple small dings and tiny cracks that I'd like to seal up before summer.

 

[David Hall22685]

Which "Devcon" product works best on repairing your Hunter 170? I've seen about 4-5 different products with that brand name but not sure which to use. Just bought my 170 last month and have a couple small dings and tiny cracks that I'd like to seal up before summer.

Devcon Plastic Welder is the stuff. It is a two part epoxy type stuff that you mix and use. I used to buy the stuff from Wal-Mart for about $2.50 but my Wal-Mart stopped carrying it. Now I buy it in the 50 ml size (over the internet) and use the Mark 5 gun to use and mix it all at the same time. It is great for larger repairs or if you anticipate a yearly going over as some of us have to do. You can get most of what you need from Amazon.

 

[heliBartek]

So I finally got around to taking few pictures of the boom modification I did this spring. First thing I did is lowering the boom attachment point by about 14" - so far so good. Everything works as it did before. I haven't had the boat out yet on any windy days but I can notice the difference in the heeling angle already. Also despite being a 6'1" guy I still have plenty of room underneath the boom without having to do any acrobatics while tacking.

Another thing that needed changing was the original boom vang setup. Two things that always bothered me about it were insuffucient purchase on the original blocks and the awkward angle at which the line was being operated.
After moving the boom down I had to shift the attach point for the vang as well. I dropped it 12" plus I added another mounting eye on the mast for an additional set of pulleys. All in all I used the existing boom vang rigging in conjunction with two more Harken small blocks to make up a new cascade vang system.

Two things I noticed right away about the new vang set up. For one its far easier to operate with increased 12:1 purchase - hardly any strain is required to get the needed tension. Another thing is the changed angle of the control line, its much easier to jam and un-jam the line from my sitting position in the back.

Last little thing I added was small pole for going wing on wing with the jib poled out. Works like a charm without having to fight with the spinnaker.

See the attached pictures.

Cheers

 

[heliBartek]

One final thought/ question .

Any of you guys out there tried playing aroung with a trapeze setup? Just wondering if the stock mast on the h170 is strong enough to take the additional stress. When using Johnson shroud tensioners standing rigging has proper amount of tenison to support this setup, just not sure if the mast will take it though.

Cheers

 

[esterhazyinoz]

On this topic, have a look at the attached photos of the 170 and the new 18. Does it look like the 18 has a lower boom height? Both photos are of each boat on a run.

 

[heliBartek]

By the look of those pictures the boom seems to be in the same spot as before. I think the marketing dept. at Hunter wanted to keep this boat as 'safe' as possible by avoiding having people wacked over the head with flying boom.
So far the modification I made on my setup has been working great. I was out last week on a gusty day and there's a noticable difference in the heeling angle. Biggest difference is in the way my boat responds to wind gusts, I have more time to get things under control before she starts heeling too far over. In the end I still have tons of room under the boom.

cheers

 

[heliBartek]

The summer has mostly passed, here in the canadian prairies, and with it most of our decent sailing weather. During that time I've had a chance to put my modified sailing rig thru its paces so here's the fianl report as promised.

To begin with there's a very noticable difference in how the boat behaves with its boom lowered full 14 inches. By my observations I've extended the limit of stable and managable crusing performance by good 3-4 knots in terms of wind speed. I'm a lot less likely to be reefing the main sail now unless its absolutely necessary. This is especially important when single handling.
The two main areas of improvment were decreased heel angle and slower response to wind gusts. It seems that the boat takes a longer to heel from about 10 thru 30 degrees thus giving you a lot more time to deal with it. Once she's past about 35 it also seems to hang a while longer before actually dumping over which usually occurs some where in the vicinity of about 40 degrees and over. Also easing of the main sheet seems to have more of an immediate effect in terms of stabilizing of the boat.

Inevitably small fraction of the performance was lost in very light winds, 4 kts and less, but it's barely noticable. With less sail aloft there had to have been some negative effect but we're talking about a difference of maybe 0.5 kts. in terms of forward speed.

While modifing the boom I also altered the boom vang set-up ( see the previous posts). That also proved to a much-needed change. In terms of the overall efficiency and ease of operation its a dramatic improvment over the original design. By incrasing the purchase from 4:1 to 12:1 and by lowering the whole assembly I was able to change the vang line control angle and with it the overall ease of use.

Overall I'm very happy with these few simple yet effective modifications. It really took out some of the less-than-desirable handling characteristics of my small Hunter. Now she's actually a very pleasant and predictable craft to sail. Next project will be the hiking straps.


Cheers

 

[esterhazyinoz]

I'd really like to see your solution on hiking straps when you have it. I was thinking of placing a bracket under where the mainsheet block is attached to the sole of the deck. I asked Hunter about this and they said that the bolts that hold this part to the deck are threaded thru an aluminium plate that is fibreglassed against the underside of the deck. I'm thinking the front end could be attached to the mast step.
Cheers

 

[heliBartek]

That's pretty much what I was thinking of doing. I wanted the straps to run the whole lenght of the boat so the aft end would be most likely attached to the rudder mount bracket. I had to repair my rudder mount last year and in the process I modified to add some strength and rigidity to it. I'm thinking of drilling two holes in it and attaching some small shackles as means of terminating the hiking straps. Once I'm done I'll post few pics.