Bow pole on a lagoon 410

[cashgar]

I am looking to add a bow pole on my lagoon 410. like to have your opinion on the length that I should install. Only saw one on a lagoon 410 length was maximum 3 1/2 long. I will use it for a asymmetric spy and for a code zero sail.

Catamaran Bow Pole KIT from forespar

Description 3 1/2" OD tube, 5 ft Long
Boat Length 36 ft - 42 ft

Description. 4" od tube x 6 ft long
Boat Length 43 ft - 50 ft

Witch one would you install and why?

Thanks

[mark_morwood]

We went with the 4" by 6' pole on our Catana 48 because I felt better with the thicker pole. We could have afforded to cut some of the length off, as I don't think the extra makes that much difference. You can remove the end fitting, shorten the pole, then put the fitting back in.

Just as a comment, I originally flew our Asym and Code 0 from the pole/sprit, but now just fly the Code 0 from the sprit, and fly the Asymmetric with a tack line frmo each bow. It lets me move the tack from the center line over to the windward hull depending on how deep we are trying to sail. Both spots work, we just find the twin tack lines to the bows more flexible (and easier to get the sock down on the spinnaker when dousing).

Mark.

[2Hulls]

Hello cashgar - either of those two lengths will work, although I'd be inclined to pick the 5' on a 410 just so it doesn't look too long and you don't end up with more $ail area than you can really use. As long as your sailmaker gets the right measurements, it can be any length you want.

But a question for you - why do you want both a code 0 and an asym spi? Will it be a real code 0 (an upwind light air sail used on race boats) or what has become cruiser vernacular for a reacher/screecher/gennaker? If the former, OK. But if the latter the reacher will cover much of the same range as an asym spi and you'd be better off with a reacher and sym spi. A sym spi will be way more versatile on deep angles vs an asym spi, if you have the hardware, which doesn't include a sprit. With a sym spi and reacher you'll be covering more of the wind angles for light to moderate wind speeds including dead down wind with very easy jibes.

Dave

[ozsailer]

Hello Cashgar,
I went through the same exercise last year and it was a bit of a eye opener. A few things I found out.

1) The 410 was never designed to have a bow sprit and there is no retro fit for this.
2) A system has to be designed to allow for all the forces that will be at work at the attachment points.
3) We were advised that we would need the services of a marine engineer to work out the loads and what was required.
4)The cost of reinforcing the inner hulls where the dolphin strikers would be was considerable.
5) It was far cheaper to go to a system where we could run a downwind sail from the bows of the boat which is what we ended up doing.
6) I spoke with the owner of a Fountain Pajot Baha 46 that had a bowsprit installed and fail miserably. Once again the FP was never designed for a bowsprit. The work was done professionally by a shipwright who put in a large backing plate on either bow to support the dolphin strikers and had removed the core in the area affected. Long story short, the loads were so great that the inner hulls distorted causing damage. A marine engineer was called in and calculated the loads which then necessitated a support plate across the interior of each hull supported by backing plates and beefing up of the inner laminate where the dolphin strikers would attach.
7) could not think of to much worse then putting a hole in your hull near the water line while flying downwind. It could really mess with your day


Greg and Sue
Sunshine
Lagoon 410S2

[mark_morwood]

Originally Posted by 2Hulls

Hello cashgar - either of those two lengths will work, although I'd be inclined to pick the 5' on a 410 just so it doesn't look too long and you don't end up with more $ail area than you can really use. As long as your sailmaker gets the right measurements, it can be any length you want.

But a question for you - why do you want both a code 0 and an asym spi? Will it be a real code 0 (an upwind light air sail used on race boats) or what has become cruiser vernacular for a reacher/screecher/gennaker? If the former, OK. But if the latter the reacher will cover much of the same range as an asym spi and you'd be better off with a reacher and sym spi. A sym spi will be way more versatile on deep angles vs an asym spi, if you have the hardware, which doesn't include a sprit. With a sym spi and reacher you'll be covering more of the wind angles for light to moderate wind speeds including dead down wind with very easy jibes.

Dave

Though we have an asym, I agree with Dave's advice. We bought the asym before the Code 0. With hindsight I would first get the code 0/gennaker and then a symmetric. We've been happy with the asym, but a symmetric does have advantages if you also have a screacher.

Mark.

[cashgar]

I agree too with 2hulls, I did have that asym form a other boat and kept it when I sold it! size was compateble. but now I like to have a sail that will stay a post on a roller furller ready do use with a little more reach that is why I like to have a code 0 on the bow pole. I will go with a bow pole 4 inch by 5 ft and I will put back plate to reinforce inside each hull!

Mark on the picture of your boat look like that your bow pole is store verticaly is it just a bad interpretation from me?

[mark_morwood]

Despite the attachment which seems to have rotated itself - I do store it vertically. It took me a couple of goes to get the geometry right, but I effectively have stays permanently attached at the waterline, running through the fitting on the pole end and are secured back at the cross beam end of the pole when the pole is down. To lift the pole I release the stays from the cross beam end which allows the pole to swing up. It was all done with dyneema and rings, and I made a thick fixed stay just shorter than the distance from the waterline to the pole end, and then did a multi-part tackle using rings from the end of the stays to the end of the pole, with the tail (with reduced load because of the multipart tackle) running back down the pole to be secured. I put eyes at the inboard end of the pole to secure the tails/ends of the stays. The geometry didn't work when I tried to secure them to the cross beam. I'll try attaching a photo.

[2Hulls]

I also "store" my sprit vertically to keep the anchor bridle from fouling the bobstays. But I have a less sophisticated system than Mark and others have - I just have two quick release shackles at the pole ends of the bobstays. I do have to use the dinghy to reach and release them, then the stays are brought up to the deck and the pole rotates upward where I tie it off to the pelican striker.

Dave

[cashgar]

Mark

I will do the same system as you did look good got more question now!!
Did you use a special rope to make the 2 stay's?
When you lower the bow or install for the first time, what is the reference of the angle or the height to set it up?

Thanks Charles

[mark_morwood]

I used dyneema for all the stays as it is strong and easy to splice. If you are not comfortable splicinug, you should get some help with that. There are very large loads on the stays.

For the horizonatal reference, I just chose one that looked right initially, and now the height in use gets set by the length of the Code 0 once it is attached to the pole and hoisted. I have a small line attached from the seagull strker to the pole to stop it flopping too far down while I rig the code 0.

[cashgar]

thanks you for all the information! it did change the way that I was going to do my setup!! in size and it was going to by fixe now I really like the idea to be able to store it vertically.
Specially when you need to park in thin spots and not get charge for a extra 5 foot in marina

thanks again

charles

[2Hulls]

Originally Posted by cashgar

When you lower the bow or install for the first time, what is the reference of the angle or the height to set it up?

I agree with Mark that there is no definitive "correct" elevation for the sprit. I eye-balled mine to have it be a straight line extension of the plane of the deck, thinking that looked best on my boat. But I think the important point here is to figure out where you want it before you measure for your sails and be able to return to that height consistently. Change this angle (or the length of the pole) and the length of the luff will change.

Back on the topic of whether your boat was designed for a sprit, the other important design aspect (in addition to the strength of the bobstay attachments on the bows) is the crossbeam. There are high compressive loads on sprits and they are applied right in the middle of the crossbeam where the bending moment will have the greatest effect. So the crossbeam has to be beefy enough to resist bending in the horizontal plane as there is no additional support similar to what the pelican striker provides for the vertical loads from the forestay. I recall that the 410 has an anchor chain track, but I don't know if this provides any help for the compressive loads generated by the sprit. Likely you'll be OK, but this may be worth getting real advice...

Dave

[cashgar]

Hi Dave

I will check with lagoon for the compressive load just to make sure that everything will by done correctly and will not affect or dommage the integrity of the crossbeam.

Thanks Charles

[WanderIVth]

Resurrecting this thread, where does one attach the asy on a 410 without a bow sprit?