Considering Some Skipjack Modifications

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Locutus
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Considering Some Skipjack Modifications

Postby Locutus » Thu Jun 07, 2018 11:08 am

My (Stevenson Designs) Skipjack became a garage queen after only three launches, and an ongoing Craigslist ad has yielded no interest, let alone a sale. So it looks like I'm stuck with it, at least for now.

I'm considering some modifications to make it more stable and easier to sail, more convenient to launch and retrieve, and to add electric propulsion. So I'm posting my ideas here in the hope of receiving some constructive feedback from our community.

Mast:
This Saturday I'm going to a nearby city to look at and maybe buy a Finland-built woven fiberglass windsurfer mast which the seller claims weighs between 5 and 10 pounds. This is MUCH lighter than my current solid fir mast, so if I can make it work should drastically improve stability (but will not provide righting moment).

Ballasted keel:
I'm thinking of either adding a lead-weighted swing keel, or cutting out a section of the keel, taking it to a lead supplier to make a mold from it to pour a matching lead slug, and bolting it in place of the cutout. Depending on size, this may provide up to 100 pounds of ballast. If this isn't enough to provide sufficient stability and righting moment, I may fasten additional lead sheets along the sides of the keel with screws. I'm hoping that a total of about 200 pounds of lead (my approximate weight and about half the boat's current weight) will be sufficient for this purpose. The boat will remain unsinkable with this amount of lead.

Cabin:
The first time I launched and after a pleasant sail I had the misfortune of turning the boat turtle due to a jibe error. Phone ruined, wristwatch ruined and a boat filled to the gunwales with water. Waves made it impossible to make headway in bailing out the water, even with a five gallon bucket.

So my next idea is to add a small cabin that can be sealed off and adding sealed compartments under the cockpit seats in order to drastically reduce the amount of water that can be in the cockpit in the event of a rollover. The cabin itself would be a tight fit suitable only for storage but the cabin itself is secondary to the purpose of keeping water out. This would be major refit, the thought of which fills me with trepidation, since I'd have to cut out a front portion of the seats and do minor surgery elsewhere.

Electric propulsion. Two options I'm considering:

1. Hang a Minn Kota off the transom. Advantages: economical and easy to install, propeller drag can be eliminated by tilt-up of motor. Disadvantages: Weight off the back end and aesthetics, may be hard to reach with the boom gallows in the way.

2: custom-built inboard drive based on this Glen-L design:

Image

Advantages: Completely hidden in rear compartment, customizable controls that are conveniently located. Disadvantages: more complicated setup than Minn Kota, constant prop drag, will require a thru-hull penetration.

Single-handing improvements:
1. Elimination of tabernacle. Since the fiberglass mast will be so much lighter, I can eliminate the tabernacle and just remove the mast for transport, laying the full length of it on the boom gallows and a fitting I'll fabricate for the front end. Quick-release pins can be used for forestay and shrouds. I found that the tabernacle made it impossibly cumbersome to raise the mainsail because the rings got caught on the tabernacle hardware. So I replaced the rings with a sail track. That was an improvement but had problems of it's own. I may be able to return to using rings if the tabernacle is eliminated.
2. The halyards can be routed over the cabin top putting it within easy reach of the helm. I want to be able to raise, lower and trim both sails with one hand, without taking the other hand off the tiller.
3. Mount the boom higher. Currently it's so low that I cannot see under it when sailing and the boom doesn't even clear the (lowered) boom gallows, so that I have to lift the boom over it with my hand when tacking and jibing. I'm hoping that the addition of ballast will make this possible without undue compromise of stability and righting moment.


Those are my ideas so far. Any constructive feedback or additional ideas are most welcome and appreciated.

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sproggy
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Re: Considering Some Skipjack Modifications

Postby sproggy » Fri Jun 08, 2018 3:23 am

I can't comment on all your suggestions as I'm not very familiar with the design but I'd be cautious about a windsurfer mast - they are designed to bend quite easily from tension in the sail and this is likely to be undesirable on a Skipjack - the forestay/jib tension would tend to bend the mast forwards or, in combination with the shrouds, put it under more compression than it's designed for. It might also not be strong enough to cope with point loads from the boom and gaff jaws, top shroud and forestay mounts. A 'birdseye' (hollow) timber mast or an aluminium one might be safer while still saving weight, or at least a carbon/fibreglass mast intended for boat use. Lifting the boom will put more strain on the mast (it raises the centre of effort of the main), making the windsurfer mast even less of a good idea IMO.

Is the current keel fixed or a lifting/swinging centreboard? If the latter, how about replacing it with a steel one rather than adding lead weight to the existing (presumably wooden) one? You're planning on electric propulsion - think about siting the battery/ies as ballast. Another possibility would be to fit water ballast tanks - then you have the additional ballast when you want it but you leave it behind when you recover the boat onto the trailer. But I'm not sure whether you could incorporate them easily.

Regarding water ingress I think I'd be tempted to fit inflatable bouyancy bags under the seats rather than closing them off as air tanks in their own right as that makes later maintenance/access easier. In the event of a capsize less water will get in (less space for it) and the boat will float higher in the water when flooded, making it easier to bale. Bags could be mounted forward too. As for the cabin....getting a couple of drybags for your non-waterproof valuables is quicker, easier and cheaper :-)

I would go for the electric outboard over the Glen-L design because of the ability to lift it from the water when sailing. Could you fit a cradle for it inside the boat so you could carry it inboard when not needed, avoiding the need to keep it mounted on the transom at all times?

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Locutus
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Re: Considering Some Skipjack Modifications

Postby Locutus » Fri Jun 08, 2018 11:32 am

Thanks for your post Sproggy. Your concerns and suggestions are well taken and appreciated. The Skipjack is a small boat of only 14 FT LOA and about 300 or so pounds. The keel is fixed and runs the length of the boat, as shown in this thumbnail:

Image

I would only consider adding a swing keel if I also add a cabin, and the keel's trunk & winch can be hidden in the cabin. Both are major refits that I'm not sure I want to tackle. I'll probably go with quick and easy solutions first like bolting some lead to the keel and fitting a lighter mast, and adding more flotation under the seats, before attempting something more drastic like the cabin. If the easy solutions aren't sufficient, then it may progress from there.

You're probably right about the motor. I just don't like the idea of cluttering up the rear end of the boat.

As for the mast, I'm going to go look at it and judge its suitability tomorrow. The Skipjack's designer actually specifically recommends windsurfer masts for their light weight, especially the carbon fiber type. The one I'm looking at tomorrow is woven fiberglass and the seller claims that it is quite stiff.

Here's an example of a finished Skipjack (not mine):

Image

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BayouBengal
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Re: Considering Some Skipjack Modifications

Postby BayouBengal » Sat Jun 09, 2018 7:29 am

I'd bought Skipjack plans a while back. Don't know when or if I'll ever build one. It's good to hear comments regarding it other than the standard glowing endorsements from the Stevenson site.

So, are you having a lot of trouble keeping it from capsizing, or will it not hold a straight coarse because of a lack of swing keel, or both? Regarding the ballast, could you possibly take a spade drill bit and drill say 1" holes along most of the length and then fill them with lead? I've read somewhere that if they capsize the water in the hull then becomes a big issue. Seeing that, I think I'd fill with foam the area underneath seats and forward, leaving only a small amount of sealed storage space forward.

I really like the idea of using the Glen-L electric propulsion design. For whatever unfavorable sailing characteristics the Skipjack may have, it's a nice looking boat and a protruding outboard would ruin that. How would the Glen-L penetrate the hull? Right through the center of the keel or would you mount it off one side of the other of the keel?

How much are you looking to sell it for and where are you located? I might be interested.

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Locutus
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Re: Considering Some Skipjack Modifications

Postby Locutus » Sat Jun 09, 2018 8:17 pm

Bayou Bengal,

The heavy solid wood mast makes it quite unstable. I turned it upside down my first time out. I just bought a Finnish windsurfer mast today...It hardly weighs anything. I'm not sure if it's beefy enough for a boat as big as the Skipjack but I plan to try it out. It'll require some serious mods to get it to work with a gaff rig.

Holding a course isn't as much of an issue as it is to complete a tack. Under full main it's doable but a reefed main with jib makes tacking difficult. In retrospect it would be better to douse the jib first before reefing.

I agree with you about the aesthetics of a hidden motor. I'll have to think about whether I want a hull penetration and where to place it.

Water sloshing around inside the boat only adds to the instability, in a big way.

I've put over $9000.00 into this build so far, using the best materials available. If I sell it I'll be trying to get as much of that back as I can but I have no illusions of getting it all back. You can see my build thread here:

https://byyb.org/forums/showthread.php?tid=3247

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BayouBengal
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Location: Baton Rouge, Louisiana

Re: Considering Some Skipjack Modifications

Postby BayouBengal » Mon Jun 11, 2018 2:43 pm

I looked over your build. You did a fantastic job with it! Following your thread and seeing all the pictures, your work is precise and your paint/finish dazzling.

I hope the new mast solves the issues. Just looking at that big chunk of rectangular shaped wood you have for a mast now, it's easy to visualize your stability problems. I'm interested to know how the fiberglass mast works out. If it doesn't, I would think aluminum would work well towards solving your problems.

If you can solve your mast problems, I'd pour or spray foam in the void areas behind and underneath the seats. I wouldn't bother with weighting the keel or adding a cabin. I just think you'd be bastardizing a well made and pretty boat, and may end up chasing your tail with the various design changes. If you decide to sell it as a sailboat, I wouldn't bother adding the motor. I think adding any more money into it will just cause you to lose more if you're dead set on selling it.

If the mast doesn't solve your problems, I'd completely shift gears and rig it with the Glen-L electric propulsion system and a canopy/bimini top and just use it as an electric cruiser.

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Locutus
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Re: Considering Some Skipjack Modifications

Postby Locutus » Tue Jun 12, 2018 11:18 am

I just discovered that Glen-L has a trolling motor version of the electric inboard plans. So I now have two choices:

http://www.glen-l.com/designs/special/etm.html

Image

I don't think I'll need the remote steering though.

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NAMEngJS
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Location: Metairie, LA

Re: Considering Some Skipjack Modifications

Postby NAMEngJS » Tue Jun 12, 2018 11:31 am

Hope the mast works out for you. I would also suggest not try to make sealed air compartments in the hull as if there ever were to be water ingress it would be impossible to bail them and you could have rot if the areas are not able to accessed to ensure their water tightness (aside from being a lot of work to do).

if you decide on any propeller set ups going with an electric option you could use the battery as a ballast weight and i would think that it would not be to hard to install a small submersible bilge pump with a float switch that could help in the event that you need help bailing out water.
All men dream, but not equally. Those who dream by night in the recesses of their minds, wake to find that it was vanity: but the dreamers by day are dangerous men, for they may act on their dreams with open eyes, to make them possible.


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