How to make Pelican mores sea-kindly...

[john avard]

Pelican is a 40yr old carvel workboat originally open, now half cabin with roof over aft deck; Length 22feet, Beam 8 feet, round bilge, built on keelson. Displaces about 3 ton.

She is uncomfortable at anchor and rolls savagely in any sort of beam sea. I added a bloody great length of railway line to the keel (approx 500kg) for little effect (made things worse) and I am wondering what to do next. Would bilge keels be better than ballast? My old fisherman friend tells me the bilge keels will act more slowly and gently than the extra weight.

I understand we need to increase the roll "moment of inertia", can anybody suggest what criteria to apply? I prefer to work on the KISS principle.

Cheers

John Avard
Melbourne Australia

[Peerie Maa]

Bilge keels may well help. Another thing to try is winging some ballast out as wide as you can fit it. Bolt it to the bilge stringer if you have one.

[Patric]

You could try using what the Pardeys call a "Flopper Stopper". Google should bring up enough DIY solutions to get you going

[Tom Hunter]

You might consider a steadying sail



Experience with them seems to vary, but it might be a workable solution for your boat.

[skaraborgcraft]

How big is your cabin? Have you raised the centre of gravity? Small mizzen sail would be the easiest thing to try, and then i would move onto bilge keels after if she still rolled too much. Some boats just do!

[wizbang 13]

Try sandbags low and outboard.( but inside)
Or , pop a short heavy mast in her.

[BrianM]

(made things worse) and I am wondering what to do next.

Two possibilities of why I think it is worse (with 500kg Steel Rail hung below the timber keel):

Greater area for beam sea to bear against.
Too much weight below the center of gravity producing "snap roll".

The bilge keels sound like a better solution as the total weight creates higher inertia of boat (less apt to react for same rolling force), but the distribution of the weight to port and starboard should also help dampen any roll. This does not include the dynamic aspect of the foils "tracking" you through the seas and their stabilizing effects.

Of course, I'd talk to someone who does these mods for a living (Naval Architect). If you've already put big hours into it, might as well make it worth you're while.

[Geoff C]

I don't know what your keel looks like but you might try adding an end plate along the bottom of it. This would have much of the effect of bilge keels but it would be easier to add and easily reversible if you didn't like it.

Also second the idea of redistributing the ballast wider.

[Jay Greer]

When I was a kid, my father had an Atkin motor sailer about the same size as yours. The boat was viciously unstable without a steadying sail up. It was a miserable boat to sail and had next to no stability of direction unless under power. Dad added a length of rail to the bottom of the keel which resulted in exactly the same results as you have gotten from yours, snap rolling. Dad finally cured the problem. He sold the boat and got one that was correctly designed to sail.
Jay

[donald branscom]

Pelican is a 40yr old carvel workboat originally open, now half cabin with roof over aft deck; Length 22feet, Beam 8 feet, round bilge, built on keelson. Displaces about 3 ton.

She is uncomfortable at anchor and rolls savagely in any sort of beam sea. I added a bloody great length of railway line to the keel (approx 500kg) for little effect (made things worse) and I am wondering what to do next. Would bilge keels be better than ballast? My old fisherman friend tells me the bilge keels will act more slowly and gently than the extra weight.

I understand we need to increase the roll "moment of inertia", can anybody suggest what criteria to apply? I prefer to work on the KISS principle.

Cheers

John Avard
Melbourne Australia

By adding 1100 ibs. of ballast you just made the boat unsafe. Creates a lot of drag too.
It is a flat bottom boat and will never be comfortable in rough seas.
Now the boat is slower AND more dangerous for rough water.
It is the wrong hull shape. It has a lot of initial stability but no reserve stability.
Also if that boat takes on water with that flat bottom in rough seas all the
water will shift from one side to the other making it more unstable.
If the boat capsizes someone could get hit in the head with that big chunk of iron and
it would make the boat even harder to get upright than it already was.
It probably would immediately sink.

What I would do is build a cabin on it that is high enough to sit in, and tie a hammock
down the center and roll into it to take a nap. Get rid of that chunk of iron too.

Read the book by Howard Chappelle called "American small Sailing Craft"
and he explains different hulls and how they work.

A photo of a Pelican sailboat.


You could try some Flopper Stoppers.