Bowsprits and Spinnakers

[Wood and Steel]

Last year I had an unfortunate encounter with a sea wall that gave me a great opportunity to learn how to fiberglass before launching this spring. Since I have a hole in the bow to patch up anyway, I'm considering the possibility of adding a retractable bowsprit under the deck for an asymmetric spinnaker. The boat is an O'day Mariner 19 CB mostly sailed on a small inland lake in Indiana. Right now I only have a main and jib, and I often find myself getting passed on the downwind leg by smaller boats in the light summer breezes that we often have here. I single hand about half the time, so a symmetric spinnaker seemed too complicated to be practical.

I'm pretty new to sailing, and definitely not a naval architect, so I wanted to make sure I was on the right track. I was thinking something along the lines of a 4' long 2" OD thick wall aluminum tubing for the sprit. That would leave two feet sticking out, and two feet under the deck, supported by a bracket on either end, with the brackets extending to the hull for support. I was unsure about the necessity of of bobstays. I was also planning on using a top down furler for ease of handling.

Here is an image of the underside of the top deck of the mariner, with the brackets poorly photoshoped, to give you a better idea of what I'm thinking:

(original image not mine)

Do my plans seem reasonable so far? Is the bowsprit even necessary? Will the spinnaker be over-powing? Should I look into other downwind sail options instead? Thanks in advance!

 

[dLj]

Are you looking for the bow sprit to be mounted under the top deck? Most are mounted on top of the deck.

I don't think you should mount under the deck, but you could use those transverse supports under the deck to attach the bow sprit on top of your deck. There are water ingress issues with running under the deck.

As far as retractable, most round retractable bow sprits I've seen run inside another tube - I didn't get that impression from your description.

dj

 

[jssailem]

Here I am sailing my 15ft Montgomery with the new asymmetrical spinaker on the home built bow sprit of 5ft aluminum pipe.

I decided that an interior designed sprit added a level of complexity to the project.
I only had a few seasons (enjoyable proof of concept) with the rig before selling the boat.
I had a new bow cap made of stainless. I had 12 screws that went through the bow hull joint and were backed to a rod that ran along underneath the hull joint. The 5-foot pipe/sprit meant that I could slide 2 feet out to serve as the sprit and 3 feet on the deck secured the sprit from moving. Having the rig on deck made all the components easily accessible. The sail was so small that handling the sail, even solo, did not need the expense of a furler. The sail tack was adjustable by running a line from the tack through a block, attached to the end of the sprit, back to the cabin. I used cleats on the stern to manage the sheets. I planned to use the sail in light wind conditions (less than 10 knots). I did not opt to install a bobstay to the sprit.

 

[David in Sandusky]

We fly our asymmetric (pictured to the left and below) with the tack line wrapped around front of the bow pulpit and fastened to the toerail. (Any bow gear would serve as well as the toerail.) On most points of sail, the only advantage I can see for a bowsprit for the asymmetric is moving its lead edge away from the turbulence off the forestay with the jib/genny wrapped around it. Not a big deal in my mind.

As always, I'm ready to learn from wiser heads if I'm wrong.

 

[garymalmgren]

Hi Wood and Steel.
RE: Do my plans seem reasonable so far? Is the bowsprit even necessary? Will the spinnaker be over-powing? Should I look into other downwind sail options instead?

Here we go

RE: Right now I only have a main and jib
Do your self a favor and get a downwind sail. You might be hesitant, but once you use one you will never look back ( except at the boats that you might have passed).
RE; an asymmetric spinnaker. a symmetric spinnaker , a top down furler
For a 19 foot boat a top down is over kill (and over capitalization. I would suggest getting a secondhand asymmetrical (gennaker) or symmetrical from any dinghy and work with that till you know what you NEED.

RE: adding a retractable bowsprit under the deck
That is A LOT OF WORK. You will need a retraction tube, lines to pull the sprit out. lines to pull the sprit in and a system to hold the sprit in the extended position. A lot of work and complexity.

RE: 4' long 2" OD thick wall aluminum tubing for the sprit.
That would do the job but you would need a simple way of mounting it that a retraction system. Check David in Sandusky's post for inspiration.

RE: . I was unsure about the necessity of of bobstays.
On a short sprit under light conditions you wouldn't need a bob stay.

I have a 24 footer with a plastic water pipe sprit.

All the best
Gary

 

[RussC]

I fabricated my setup in 2018 (Mac 25') and it's worked out great for me. I didn't need much length to get out far enough to clear the bow rails so mine is fixed but set up very similar to your design idea. asymmetrical and deploys out of a bag on the deck single handed very easily. it's not rocket science as long as you have basic skills. don't overthink it. just grab a hole saw and go for it