Add weight in bilge for singlehanding?

Discussion in 'Sailboats' started by 255grizzly, Jun 18, 2016.

  1. 255grizzly
    Joined: Jun 2016
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    255grizzly New Member


    I sail an Olson 25 sailboat single-handed (this boat I am considering adding weight to the bilge and was wondering if this forum would have some advice.

    Normally, O25's are sailed with a crew of 4-5 people, 3 of whom are usually on the rail. I like to sail it singlehanded, which really creates a problem when it's windy and choppy. It can be very hard to keep the boat flat and there is lots of leeway. I have reefed and used smaller headsails - both of those help some, but not as much as I would like. So, I am wondering:

    1. Would it make sense to add weight in the bilge?

    Note: I'm ruling out complicated / expensive things like adding a bulb keel or moveable water ballast.

    2. If so, how much should I add?

    Let's say there's ~540 pounds on the rail (3 guys, 180lbs each)... do I need that much? Or because the weight would be in the bilge/lower in the boat, less?

    3. Where should I put it, right over the keel I assume?

    4. Is it okay to use a water ballast bag for this?

    I would make sure there was an enclosure to hold it properly. But I like the idea of using one of these because they look relatively inexpensive (I saw some for wakeboard / ski boats.) Also, vs. lead shot or lead ingots, it will be relatively easy to install and relatively easy to adjust. And, it won't affect the design / ruin it for true one design racing.

    Thank you for your input!
  2. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    Regaining the righting moment (540# on the rail) means the weight needs to be on the Windward rail.

    540# x ~5' = 2700 ft-#.
    Water ballast over the keel only has has
    540# x ~1' = 540 ft-#. Hardly worth it IMHO.
    This assumes desirable heeling, which results in the center of bouyancy ~1' off the keel line (to leeward).

    You would really need water tanks on each rail, holding 540# with the water being able to be moved side to side on each tack. Perhaps with air pressurization?

    This is to get the same benefit as the rail meat.

    I've never heard of this being done, but that doesn't mean anything. :)
  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Agreed, you want the weight to replace the crew you're not carrying, so . . .

    Over the fin will work, but you'll need a lot more than the rail meat, because of it's location. Water ballast will do, though some old school sand bags will do in a pinch too, though you'll tire quickly tossing several 50 pound bags from one side to the other.

    Moving 9 cu. ft. of water from rail to rail will require some engineering, but is possible. In light air, I don't think this would be all that necessary, but in moderate and heavy air, certainly a benefit, to keep this puppy in the groove.
  4. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    I agree with upchurchmr and Par.

    Adding that weight downstairs isn't going to come even close for making up for the missing rail meat.

    That being said, doing it may noticeably improve the situation.

    This is for three reasons:

    1.) It will make the boat 540 lbs heavier, causing to sink down to the waterlines it was probably designed to sail on. Most likely it was intended to sail with a four person crew. That would be 4 x (150 to 200 lbs), or 600 to 800 lbs. With just you on board it is probably at least 400 lbs lighter than intended. Being this much lighter may be causing it to float an inch, more or less, higher than it was designed to.

    2.) it will lower the Center of Gravity, making the righting moment slightly greater. And

    3.) it will improve the heft of the boat, giving it more momentum to bash through a chop.

    I suggest getting a bunch of sand bags and placing them as low and close to the center line as possible. I would go with about about 800 lbs for starters, then see what happens.

    This experiment would not permanently alter the boat in any way, and would be relatively inexpensive to do.

    I would try this first with full sail, then with a shortened rig, in a fresh breeze, to see how it goes.

    Another change to consider is a new main sail with the same foot length but a shorter hoist. Perhaps you can get a used main and have it re-cut. This would give back some of the sail area lost due to reefing, while moving the Center of Area (CA) lower. This would also move the CA aft a bit, to cut down on lee helm, if there is any.
  5. bergwerk
    Joined: Jun 2016
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    bergwerk Junior Member

    Nice boat. I had a 30 which I raced PHRF out of Alamitos Bay in SoCal until I lost my crew when my sons and their friends graduated and moved on.
    I sold the Olson and replaced it with a Moore 24 (your boat in an earlier incarnation) with which I kept racing solo though I weigh only 135 lbs. Ullman Sails in Newport Beach understood my needs and cut me a radical new main that greatly helped.
    Work with the best local sail loft you can find and be sure to explain your needs. Their sails will transform your 25 in ways that will amaze you.
    The goal in ULDBs is just what the name says.

  6. tom28571
    Joined: Dec 2001
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    tom28571 Senior Member

    I doubt any reasonable amount of inside ballast would satisfy your need for replacing crew on the rail. It simply does not offer a lot of righting moment until you are heeled pretty far over. It will make the boat feel more stable at all heel angles though and you may find that sufficient for single handing in reasonable weather. Yes, that sounds like a contradiction but it is why many water ballasted small boats feel more secure for single handing.
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