Bowsprit Launching Tube Through Bow

Expertise and know-how available for all builders from Class Members

Moderators: admin, Kevin

Bowsprit Launching Tube Through Bow

Postby BullShip » Mon Apr 22, 2024 2:44 am

I've searched the past building notes and I don't see discussions about the bowsprit coming through the hull. It seems the right way to go but it opens up a bunch of questions, for me at least. I've searched the internet looking for how these work. How do you keep water out of a big hole in the front of the boat? I guess that is my biggest question. If anyone could explain that and any other information that might be helpful... The system used to retrieve the pole and extend it. I'm thinking that a starboard launch side would be the best option since we tend to race rounding marks to port.... Anyway, any thoughts or comments would be helpful.

Chris
BullShip
 
Posts: 2
Joined: Tue Apr 16, 2024 9:22 pm

Re: Bowsprit Launching Tube Through Bow

Postby admin » Mon Apr 22, 2024 3:57 pm

Hi Chris, good question.

I tend to take a low-tech approach to most things in life. We simply plugged the forward end of the pole with a rubber ball the approximate size of a tennis ball. The hardware attachment that keeps the tack line bullet block firmly attached to the forward end of the prod keeps the ball from penetrating any further into the tube. We may put a couple of pieces of white vinyl tape over the end to make sure the ball doesn't pop out (in conditions that are more boisterous -- like weekends with a lot of powerboat traffic).

Pole out and in is easy...bungie cord the aft end of the pole to frame 53.5 or 89. Use bungie cord stout enough to yank the pole back when it is uncleated.

And a single bullet block on a forward frame (18) to a pad eye on the aft end of the pole will get it to scoot out easily, belay "pole out" line to a cam cleat on the cockpit bulkhead. Eezy peezy.

Drawings are somewhere on the Forum I think, but it's easy to reconstruct one if you'd like!
admin
Site Admin
 
Posts: 474
Joined: Fri Mar 25, 2011 4:17 pm

Re: Bowsprit Launching Tube Through Bow

Postby Warren Nethercote » Tue Apr 23, 2024 12:42 am

My sprit comes out of the bow, on the centreline. I was going to add a half rubber ball as a 'plug' but it would only work when the pole is retracted, and my cockpit sole goes all the way to the bow - so if water comes in the front it goes out the back. I have a bigger hole in the front to worry about, as is obvious!

Edit: Note that the pole is tapered so it is a tighter fit on the 'hole' when extended, but still not watertight. The meter-sized J-Boats and Melges seem to live with sprits fed into the interior, but perhaps they have better bilge pumps ...

I will add another post about extension and retraction, as that picture is on a different computer.
You do not have the required permissions to view the files attached to this post.
Last edited by Warren Nethercote on Tue Apr 23, 2024 1:08 am, edited 1 time in total.
Warren Nethercote
Boutilier's Pt, Nova Scotia
Build License 573
Build log: viewtopic.php?f=3&t=364
Warren Nethercote
 
Posts: 410
Joined: Sat Apr 25, 2015 2:11 am

Re: Bowsprit Launching Tube Through Bow

Postby Warren Nethercote » Tue Apr 23, 2024 1:03 am

We manage the pole extension and retraction like a 29er, 49er or any other skiff.

There is no independent sprit extension control, instead it is extended when the spinnaker is hoisted (actually, the extension is typically the last thing to happen since the halyard loads to hoist are lower than those to extend). Note that we tube launch (and recover), although we have bag launched a couple of times using the same sprit extension method. Bow sprit retraction is by bungee - a long bungee is needed, running almost twice the length of the boat. The extension system is similar to that shown in the picture, although our tack line is not like that. Instead we have a sprit--end ferrule (second picture, not of Blondie) and the tack line feeds down the centre of the pole and dead ends on the mast post. The tack line length is set to have the tack at the sprit end at full extension. When the pole retracts it creates slack in the tack line to allow the chute to be put to bed.
You do not have the required permissions to view the files attached to this post.
Warren Nethercote
Boutilier's Pt, Nova Scotia
Build License 573
Build log: viewtopic.php?f=3&t=364
Warren Nethercote
 
Posts: 410
Joined: Sat Apr 25, 2015 2:11 am


Return to Building an i550

Who is online

Users browsing this forum: No registered users and 20 guests

cron