Arch on bigger hunters

[chowdan]

Hey all,

I have been walking docks near me and I've noticed hunter uses an arch/gantry setup for the mainsail traveller.

I do not own a hunter and only been in the cockpit of one once and that was to help a fellow boater out with his windlass. The setup has gotten me thinking about my boat and optimizing the companionway to be a bit more.... comfortable.

That said, my idea is to raise my traveller up to be above my dodger, and raise my dodger up about a foot, which would allow me to enter/exit the companionway potentially without having to crawl In on my knees.

I'm not 100% sold on placement of the gantry as I may switch to end boom sheeting, but I was hoping some hunter owners could provide feedback on their archs, possibly some people who can provide photos as well.

I'm thinking of having this built out of aluminium which would reduce weight and match my Atlantic Towers arch located on the stern for solar.

What diameter is the stainless tubing on the hunters(40+ footers), does anyone have ideas on tube wall thickness? Mainly trying to get an idea of thickness sizing so I can spec the aluminum appropriately.

How are they bolted to the deck? It looks like 4 bolts per foot, how big are the backing plates? Any photos from the underside?

How has the arch handled sailing in high winds? My boat is very heavy(45k lbs) and likes 18-20knts under full sail to get her moving at hull speed. Gusts into mid 20s are not a huge problem for us and it's usually around 25knts consistent when I throw in my first reef on the mainsail(headsail usually reefed in a bit if we get gusts to 25).

How does the arch handle accidental gybe/tacks? Any flexing?

Much appreciated everyone!

 

[Ralph Johnstone]

You're definitely on the right track (as shown in your drawing) but I would strongly suggest you crawl all the docks near you looking at ALL size later model Hunters for ideas as they all have SS arches. Take a thousand pics from every angle to aid in your planning.

My 1999 Hunter was the last model of all sizes with the FG arch. Wish I had held out another year for the SS arch.

 

[chowdan]

You're definitely on the right track (as shown in your drawing) but I would strongly suggest you crawl all the docks near you looking at ALL size later model Hunters for ideas as they all have SS arches. Take a thousand pics from every angle to aid in your planning.

My 1999 Hunter was the last model of all sizes with the FG arch. Wish I had held out another year for the SS arch.

Thanks for the response. As I head towards home and get near marinas ive been walking around to see how they are done. Hard to walk marinas when I've only stayed 3 nights in them over the last 70 or so days.

That said I should be back in Seattle by the 30th and will be able to meander docks again.

Out of curiosity, what was the reason you prefer the stainless over fiberglass arch? I've slightly considered building my own glass arch, but not 100% sold on the idea(I have other winter projects that need being done and this is a logical one to outsource).

 

[Ralph Johnstone]

Out of curiosity, what was the reason you prefer the stainless over fiberglass arch?

Just the ease of adding anything additional at a later date.

My boat came from the factory but someone, in their infinite wisdom, omitted the traveller. It cannot be added later on the FG arch as the attaching bolts for the track must be through bolted with nuts. Impossible with the FG arch but a walk in the park to add a traveller at a later date with a SS arch.

 

[patfarrell1949]

Our Hunter is a 2010 50CC and I can tell you the only thing I'd be concerned with is understanding and designing for the possibly enormous loads that the arch will see at times. I'm a long way from our boat just now so can't say the dimensions of the tubing used but would guess around 2 inch. In order to reduce overall height for road transport its actually bolted together a foot or so above the deck. Most importantly I believe the attachment points on the deck have been beefed up specifically to take the loads. It looks like you're thinking of bolting the base near the side ports...you probably need to consider if that area will support the loads and especially the flexing / shock loads. Finally how much extra headroom are you expecting under the arch? On our boat the dimension from bottom of the boom to bottom of the arch is several inches (maybe 6 to 8 at least), would that be enough? Have you considered moving the traveler and therefore the arch back, closer to the end of the boom, maybe near to your winches...possibly stronger deck support there and no interference with your companionway entry? Good luck!!

 

[Daze]

You can find some information that you are looking for in the document link located in the "Ask A Hunter Owner" Forum. I've attached a link to a 2006 H49 (I own a 2007) https://www.marlow-hunter.com/wp-content/export/Owners-Manuals/49 Owner's Manual 2006.pdf
On pages 77 and 78 of the pdf or 44A and 44B of the manual there are drawings, attachment info, etc. for the arch on the Hunter 49. There is likely other arch drawings of other owner manuals located in this link Index of /wp-content/export

Good luck with your project.

 

[calypso36]

Or, buy a Hunter. I'm not being facetious. The arch and traveller must handle tremendous loads. Mine is a 36 and when I readied it to transport by truck it took two very strong fellows with broad shoulders to lift the top half of the traveller down to secure for the trip. You may also run into challenges if you wish to sell one day and the surveyor provides his own assessment of the add-on.

 

[jssailem]

Strength and stability would be my first concerns. You could build the unit out of stout aluminum tubing. Masts and booms use anodized aluminum for their construction.

Do you have enough room between the deck and the bottom of your boom?

Your diagram shows straight legs for the arch. You likely will need to widen the base and make the top of the arch more narrow. These are engineering concerns to address the issues mentioned by @patfarrell1949.

Then there is the rigging.. The Hunter design page shows the elaborate rigging they installed.

 

[senang]

The forces on the arch are tremendous. Think of a surprise gibe in a strong breeze. You do NOT want to have the arch bent, broken or ripped out of the deck. You can do it, but plan for a very big safety factor.

 

[artboas]

I would consult a naval architect on this.
There are many factors that go into rig design, and you don’t want to be experimenting with this,
The arch on my 49 takes huge loads. Initially, I thought the size and construction of the stainless tubing was overkill, but it’s not. It will flex if the boom jibes, and you can see it vibrate.
The sections that attach the arch to the deck are actually solid cast stainless. Very beefy stuff.
You definitely need to put solid numbers to this, and rely on people who design rigs for a living.

 

[wpatch]

I have an 04 36 and the arch is built extremely tough for 2 main reasons.

1) As others have said stress on it has to be high. I would not want to know tolerances etc and stress levels. Also I think aluminum may flex too much to be practical.
2) Access. I climb the arch to open and close the main sailbag or do any work on the end of the boom or reef lines. I have gone up under sail to deal with issues, and I wouldn't want anything not super tough.

I get your issue though, having sailed on a lot of boats, having the traveler over my head is lovely on our Hunter, and it does make solo handling much easier.

This may be a neat idea for you: main sheet arch construction