bulb bow - SailNet Community
 
LinkBack Thread Tools
post #1 of 3 Old 09-29-2009 Thread Starter
Junior Member
 
Join Date: Sep 2009
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
advice needed about bulb bow

i want to build FRP fishing vessel 19m is it advisable to make bulb bow

Last edited by skomani; 09-29-2009 at 01:19 PM.
skomani is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 3 Old 09-30-2009
Senior Member
 
Join Date: Feb 2002
Posts: 221
Thanks: 3
Thanked 3 Times in 3 Posts
Rep Power: 14
 
No offense, but if you are going to build a 62 foot fiberglass boat, you should really take a few semesters of boat design classes or avail yourself of the services of a naval architect, and not just ask questions like that on an internet forum. Remember "I read it on the internet" is as scientific as "I heard it on the telephone".
jgeissinger is offline  
Quote Quick Reply Share with Facebook
post #3 of 3 Old 10-01-2009
Moderator
 
Jeff_H's Avatar
 
Join Date: Feb 2000
Location: Annapolis, Md
Posts: 6,959
Thanks: 5
Thanked 164 Times in 133 Posts
Rep Power: 10
     
I strongly but respectfully agree with JGeisinger's points above but to answer your question, the answer is 'No', bulb bows do not belong on monohull sailboats of that size or on most multihull sailboats of that size either.

You call simply call this a fishing vessel, which is too loose a description to tell what your plans are. So while there may be a reason to use a bulb bow, at 62 feet it is pretty unlikely that a bulb bow makes sense if this is a sailing vessel and even if it is not.

There were a lot of experiments with bulb bows on sailboats back in the 1970's and they were not found to offer any advantage and to offer a number of major disadvantages in heavy going and in light air. Unlike ships, sailboat bows have a variety of functions including tracking and preventing leeway, and operate at the interface between air and water, sometimes above, sometimes below, and often exposed to the full force of waves.

The current thought on designing bows that offer a seakindly motion, low resistance, reduce spray and greenwater aboard, and which help with leeway and tracking is to use a fine bow which is the opposite of using a bulb bow.

The reason that bulbs work on ships complex but is partially related to their slenderness, slab sides and comparatively blunt bows, solid state water flows, and the typical operating condition of minimal wave impact on the bulb.

Jeff


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Curmudgeon at Large- and rhinestone in the rough, sailing my Farr 11.6 on the Chesapeake Bay
Jeff_H is offline  
Quote Quick Reply 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:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Replace bulbs in cabin lights with LEDs n0w0rries Gear & Maintenance 34 09-28-2009 07:00 PM
How to Steer in Waves Carol Cronin Racing Articles 0 06-10-2002 08:00 PM
The Basics of Doing the Bow—Part Two Rich Bowen Racing Articles 0 04-03-2002 07:00 PM
The Basics of Doing the Bow Rich Bowen Racing Articles 0 03-20-2002 07:00 PM
America's Cup Design Retrospective Bruce Kirby Racing Articles 0 03-15-2000 07:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome