Increasing displacement with bilge freshwater storage? - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Chat  
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 


Like Tree2Likes
Reply
 
LinkBack Thread Tools
  #1  
Old 4 Weeks Ago
Member
 
Join Date: Jun 2013
Location: Saratoga Springs
Posts: 88
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 2
71Seafer34 is on a distinguished road
Increasing displacement with bilge freshwater storage?

Greeting again everyone. I have a quick idea I wanted to pitch to the group. Our boat being a shoal draft Seaferer 34 has a reputation for being slightly tender (3'9" draft with C/B up, 4800 LB lead ballast). I have been doing some reading into this, the motion comfort ratio, and general sailboat design and am wondering if perhaps adding water tankage to the bilge would be a good solution to aid our vessels sailing characteristics and stability. I know that heeling effectively adds waterline length and aids in our speed but too much can also make for an uncomfortable passage and lead to premature reefing. Interestingly, in original literature for our boat the boat was outfitted with tankage in the bilge, which leads me to believe that perhaps she was engineered to have this added weight down low. Of course ours, being originally sold as a bare hull to the original owner, does not have this feature. So, aside from configuring our sail plan with added reef points and getting as much of our general stores down low, do you all see a large benefit from adding the water stores as well? I believe I can fit two flexible bladders on either side of the centerboard trunk (see our construction pictures) without taking anything away from the bilges deep sump where our bilge pumps are located. Projected weight added being between 500-650 LBS. Assume I will make those bladders stable and protected from rupturing in all conditions. I really love our boat and want to make her as seaworthy and capable as possible as both a coastal cruiser and open water vessel, although I do not think she is necessarily ever going to be a "safe" blue water boat. Thanks for the input. I would like to hear all angles on this if you all have the time.
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 4 Weeks Ago
TomMaine's Avatar
Senior Member
 
Join Date: Dec 2010
Posts: 425
Thanks: 6
Thanked 21 Times in 20 Posts
Rep Power: 5
TomMaine is on a distinguished road
Re: Increasing displacement with bilge freshwater storage?

Our 1961 Alden Challenger was designed with built in fuel tankage well below the sole and around the centerboard trunk(like what you're planning).

The 80 gallon tank is built into the fiberglass hull and has 4 large 1/4" steel plates to cap the tank area. A few boats had problems with leaking keel bolts. Some removed the tanks(they were so large because the boats came with Graymarine gasoline engines).

Even though the Challengers have bolted on long lead keels, Alden(when they were still designing boats) recommended added low ballast in converting the tanks. The steel plates were part of the reason but the fuel down low may have been considered in the boats stability(centerboarders need special thought to stability forces).

As well as the 80 gallon diesel, our boat has 2-40 gallon water tanks at sole height/below the waterline. A lot of weight down low that is helpful for stability.

In the end, even though any weight is detrimental to light air sailing performance, you need water! And that area is a great spot for fluid storage. Flexible tanks that fit nicely sound like a good idea to me.
__________________
Tom Young sailing a 1961 38' Alden Challenger, CHRISTMAS out of
Rockport, Maine.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

'I'd have written a shorter post, but I didn't have the time', Mark Twain.
Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 4 Weeks Ago
Senior Member
 
Join Date: May 2006
Posts: 276
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 9
mike dryver is on a distinguished road
Re: Increasing displacement with bilge freshwater storage?

Hi TomMaine!! thanks for the USHarbors sight just joined!
TomMaine likes this.
Reply With Quote Quick reply to this message Share with Facebook
  #4  
Old 4 Weeks Ago
Senior Member
 
Join Date: Mar 2012
Posts: 658
Thanks: 26
Thanked 24 Times in 24 Posts
Rep Power: 3
barefootnavigator is on a distinguished road
Re: Increasing displacement with bilge freshwater storage?

I can't remember the numbers but I think they say every pound you take out of the rig adds 10 to the ballast so to speck. New rope rigging might be a easy way to start this project, as would well shaped sails. Bilge water tanks are always good but easier said than done.
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 4 Weeks Ago
Junior Member
 
Join Date: Jul 2014
Location: Lewes De
Posts: 19
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
Jim_W is on a distinguished road
Re: Increasing displacement with bilge freshwater storage?

You could put a bunch of bricks or lead or anything heavy in the bilge before going to the expense of tanks to see if it improves performance.
Reply With Quote Quick reply to this message Share with Facebook
  #6  
Old 4 Weeks Ago
Member
 
Join Date: Jun 2013
Location: Saratoga Springs
Posts: 88
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 2
71Seafer34 is on a distinguished road
Re: Increasing displacement with bilge freshwater storage?

Unfortunately, the rig is all but done, and all new, luckily we did not go up any wire sizes other than on the forestay. That said, we lack things like a radome or mast steps. Dyneema was a consideration but I just couldn't subscribe to it fully, I trust my stainless over all else. The reason I suggested the water tankage is mainly because we need it. We have a watermaker but I still would like to have surplus water for things like our shower and dishes, potable water will be separate from the bilge system if implemented.

I guess what I would really like to know is given our shallow draft are we really gaining any mechanical advantage over the force of the rig in keeping the boat righted by just adding weight without the leverage? When I built out centerboard I put as much lead in it as possible but that was really only to ensure it does not sweep up at speed. I suppose I could consult a naval architect but I wanted to ask here first. Has anyone experienced a cause and effect situation where they effected their boats heeling and to weather performance by adding weight to the bilge/ballast?

Last edited by 71Seafer34; 4 Weeks Ago at 10:49 PM.
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 4 Weeks Ago
deniseO30's Avatar
1934 Chickering
 
Join Date: Nov 2006
Location: Bristol pa
Posts: 6,498
Thanks: 53
Thanked 105 Times in 94 Posts
Rep Power: 10
deniseO30 will become famous soon enough deniseO30 will become famous soon enough
Re: Increasing displacement with bilge freshwater storage?

I'm Guessing you have not really used the boat or even sailed it yet. Why not try to stop over thinking all this until you get her "out there" ?

What you were "told" doesn't mean squat, fear of heeling is real and imagined and will subside as you get used to the boat.
__________________
Denise, Bristol PA, Oday 30. On Tidal Delaware River, Anchor Yacht Club. New Website!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

My boat is for sale.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #8  
Old 4 Weeks Ago
Member
 
Join Date: Jun 2013
Location: Saratoga Springs
Posts: 88
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 2
71Seafer34 is on a distinguished road
I don't consider this overthinking anything. You are correct in your assumption that we have not used the boat. we have been living aboard another vessel for the last few months and I can assure you I would not want to cut into a freshly laid sole to retrofit water tanks into my bilge while underway or living aboad. Supporting said tanks and running plumbing is exponentially easier at the current stage of our project. Hence my planning ahead on this particular topic. Sometimes it's nice to learn from other people's experiences instead of repeating the same old mistakes. Also, this has nothing to with fear; it has everything to do with vessel stability, functionality, and safety. Thanks for the input
Reply With Quote Quick reply to this message Share with Facebook
  #9  
Old 4 Weeks Ago
celenoglu's Avatar
Senior Member
 
Join Date: Dec 2008
Posts: 609
Thanks: 0
Thanked 8 Times in 8 Posts
Rep Power: 7
celenoglu is on a distinguished road
Re: Increasing displacement with bilge freshwater storage?

Water tanks are for you water needs. They might add some weight below your water line if they are full, but fresh water is for consuming. You can never keep them full when you really need them. Adding some more weight to your keel or to your bilge is a better solution. The best solution is to buy a boat with required specs.
Reply With Quote Quick reply to this message Share with Facebook
  #10  
Old 4 Weeks Ago
mitiempo's Avatar
Senior Member
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 7,355
Thanks: 0
Thanked 85 Times in 76 Posts
Rep Power: 8
mitiempo will become famous soon enough mitiempo will become famous soon enough
Re: Increasing displacement with bilge freshwater storage?

I agree water tanks aren't ballast just weight that is sometimes there.

I your boat matches the numbers here SEAFARER 34 CB sailboat specifications and details on sailboatdata.com I would not be concerned with stability. 34 ft with a 10ft beam and a 39% ballast ratio denotes stability to me. As far as qualified for offshore use I would say it is as long as items such as rigging and cabin closures are sufficient. Centerboard boats have an advantage in the rough stuff in any case as with the board up they are a lot less likely to trip over the keel in large seas the way a deep keel boat can.

Finisterre has similar numbers and she crossed a bit of open water in her time.
Sparkman & Stephens: Design 1054 - Finisterre
oysterman23 likes this.
__________________
Brian
Living aboard in Victoria Harbour
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Increasing Outboard Prop Depth? sparrowe Gear & Maintenance 7 03-23-2014 03:48 PM
Increasing flotation mattnj General Discussion (sailing related) 25 03-31-2013 12:31 PM
Increasing purchase on cunningham and outhaul. zz4gta Gear & Maintenance 14 03-03-2009 11:09 AM
Consequences of Boat Storage: Gelcoat and Bilge Waymar83 Gear & Maintenance 21 08-26-2007 12:22 AM
Increasing Sail Area dm567 General Discussion (sailing related) 33 01-18-2007 11:52 PM


All times are GMT -4. The time now is 10:07 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2015, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.