Sacrificial Keels for Catalac Cat

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4Henry

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Hello:
I am another monohull sailer who "may" have become convinced that a catamaran better suits my needs. I am interested in the older, plodder types [as I've read one owner describe his HT]- the Heavenly Twins and Catalac [Catalac 10m preferred for boat, 9m preferred for price]- she needn't sail tight to wind, as winds blow up/down straits in any case in my location and currents are stong. But, she must be made fit to take the beach in river flats that are seldom soft mud. My grounds are tidal- spring tides can be over 20' and docks/marinas are scarce.

Would owners and knowledgeable sailers please weigh in on fitting sacrificial keels to a Catalac? May they reasonably be fit to a Catalac's hulls so that she may take the beach without injury?

I've seen the HT on the hard- no problem affixing any of several possible protective keels on bottom of her short, stout, integral keels. But I've only seen the Catalac in photos [hard to find a boat on west side USA]. She does not have keels- so protection must adhere to the hulls themselves. Yet, being a British boat, seems likely she's 'beach-able'- suggestions?

Will she handle the "thuds" of gentle swell as tide eases from under her?
Can protective strips be beefed and affixed to handle a pebbly and/or sandy bottom as well as a muddy one?
 
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4Henry,

welcome to the forums.

I think the keels you suggest would be a good idea, not least in that they should help a little with a grip on the water when going to windward; I knew a Catalac owner ( don't know which model ) who reckoned to go anywhere upwind required the leeward engine on...

The keels also need to be strong enough for the considerable side loads when sailing.

I knew a late model Heavenly Twins, it was a very nice boat to live aboard but unbelievably slow, the owners were experienced sailors who thought they could make anything go but this one had them scratching their heads in amazement, they sold her within one season; I do think the HT infinitely more seaworthy than a Catalac though.
 
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you may do better posting that here:

http://www.multihulls4us.com/forums/forumdisplay.php?7-Multihull-Sailing-Forum

i have had a catalac 8m, nice floating caravans.
just dont expect them to sail into the wind.

very comfortable, would have one vs a HT any day. HT much smaller inside.
multihull world on the south coast may well have both in their stock of second hand multihulls, worth a look.

previous owner sailed it to the med and back, canals one way, biscay the other way.
seemed perfectly safe to me, no keel to trip over, so would just slide sideways.
 
There are lots of Catalacs on drying moorings up and down the country so I would not be concerned about dryings out on the hull. However if the mooring is on rocks and pebbles then it would seem sensible to think about protecting the hull. It would be reasonably simple to fix a semi-sacrificial hardwood bearer strip to the hull but I have never seen this actually done. Another approach would be to re-enforce the hull in the vee at the bottom from the inside. from memory all the hull is accessible (apart from the water tanks in the 9M) and it would be possible to strengthen the bottom to be massively strong and thick to resist any sort of wear/impact damage. As others have remarked the Catalac hull shape is both its strength and weakness i.e. it does not go to windward too well but in the event of heavy weather or waves on the beam it will just slip sideways without causing any problems.

The catamaransite web site is a wealth of information on the Catalacs and there is a Catalac Owners section in the Multihulls4us site where you can communicate with many other Catalac owners about your ideas.
 
I think if it were me I would consider adding extra layers of glass or even kevlar to the bottom of the keel. This will both toughen up and reinforce the keel and even if it is damaged the original hull will still be intact. On an old boat it may already be well worn (damged). Alternatives would be to add more GRP to the inside of the keel (hull). Wood would have to be attached by bolts giving a possible source of leaks etc unless you cna successfully bond wood to the keel. The amount of keel you are propopsing to add will not affect the performance to windward or resistance to capsize.
good luckl olewill
 
Depending on the profile of the existing keel section you can either attach a section of stainless steel angle "V".
Or ,if it is flat, attach two angle :. .: preferably overlapping at the bottom.

I changed the profile of our heel bottoms to tale the two angle version as we do spend a lot of time sitting on the beach or drying out on sand bars.

Good luck and fair winds. :)
 
The Stainless steel angle comes in a number of sizes and thickness as well as grades and can be re profiled very easily.
I installed the two angles with an overlap to widen the support area and then pre drilled holes and backfilled with Micro-fibres and epoxy resin then re-drilled the the required size for simple bolting on. I also lined the angle on the inside with release tape(silicon) and added more Micro-fibres and epoxy resin to fill any voids.

The tape will ensure they come off easily when replacing later if ever.

Good luck and fair winds.
 
With respect to stainless shoes on the bottom, the centre part of the hull bottom is flat but tapers to the front and rear to become an acute angle (perhaps 60 degrees) so the shaping and fitting of any shoes would be quite a fiddly job.

The idea of fitting sacrificial wooden runners bonded only to the bottom has appeal but if only bonded what about the wood swelling etc and loosening any bonding, even with epoxy?
 
I fitted hardwood extra bottoms to the fins of my Commanche, with epoxy goo. Easier than on a Catalac though. My fathers' 9m had non and beached with no problem whatsoever and he had it for 15 years.
 
catalac08 said:
With respect to stainless shoes on the bottom, the centre part of the hull bottom is flat but tapers to the front and rear to become an acute angle (perhaps 60 degrees) so the shaping and fitting of any shoes would be quite a fiddly job.

Fitting the first set of stainless steel or even other materials will take a bit of setting up, drilling, filling and re drilling holes to secure you choice of material. It sounds like you would the angles for the flat section, one each side with an overlap on the underside, the 'V' sections fore and aft would a single and little bit of fairing at the transition from angle to square. Curves in the flat or 'V' areas are just a matter of cutting slots in the vertical sides, more curve more slots.

These will outlast any timber and not attract nearly as much growth.
Click to expand...

Good luck and fair winds. :)
 
Thanks to all for your thoughts, re: beaching Catalac 9m.

I misspoke in my initial query.
I used the words 'affixing sacrificial keels" to the boat's bottom. Indeed, I was thinking 'sacrificial shoes.'

Apparently, as members have mentioned here, any sort of added keels may increase her windward ability but at the same time decrease her safety [she won't slide and may trip on downside of wave]. Another member wrote that "the amount of keel you are proposing to add will not affect the performance to windward or resistance to capsize" and I think that's right, since a sacrificial inch to take the bottom would I think be all that is necessary.

I will also refer to the Catallac owners at the "multihulls4us" site, as one member here advised; and I have scanned the helpful information on Catamaransite as a member here suggested, though by no means have I exhausted all the useful material found there.

Thoughts in this thread seem to agree that reinforcing the bottom of hulls is the best idea, with question of how best it be done.
Ideas include:
-stainless keel band- sheathe hull bottoms in stainless. [Another member suggests that fitting keel shoes would be problematic, due to taper of hull forward and aft]
-kevlar hull stengthening [sheathe hull bottoms in kevlar]
-extra layers of glass for hull stengthening
-angle "v's" of stainless- bolted through.

A couple thoughts in response to the suggestions here, please:
To Catalac08: I too would have more doubts as to wooden shoes except that I've seen it done on an HT that had circumnavigated with the arrangement intact- never had to replace it. It was simplicity itself: didn't even use hardwood: two layers of 1/2" ply glued [epoxied] to the bottom of the HT's keels. That's it. I too would have doubted glue would hold, especially given the unavoidable pounding and grinding as the boat settles/rises with the tide. But here was proof. [At least, on the HT- which admittedly is far easier to fit, given the straight, fixed run of the keels].
Two elements of this arrangement make it especially attrractive:
-no through-hull fittings.
-if/when need to replace the shoes, cut the remains of old shoe and glue to it a new piece.

The owner was strongly against drilling to secure the wood shoes.
I suggested glassing the wood strips onto the keels, but the owner asked 'why? Works fine as it is.'

However- as responses here mention, not so simple a matter on the Catalac, given the Catalac's lack of keels and the varying shape and angle of her bottom.

Old Saltoz, I like the idea of angle stainless. I think I grasp the basic idea, however, I am unclear about how your attachment and use of microfibers with epoxy. May I email for more detail?

Though- I'd prefer a solution that did not include drilling through the hull: won't bolted steel shoes work with the tide, however slightly? -Thus the bolt-thrus may represent potentially serious problems later- ?

Sacrificial shoes may not be as easily done as on a bilge keeler or on the HT, but apparently they can be and have been serviceably added to Catallacs: thanks for all thoughts and comments.
 
4Henry said:
Hello:
I am another monohull sailer who "may" have become convinced that a catamaran better suits my needs. I am interested in the older, plodder types [as I've read one owner describe his HT]- the Heavenly Twins and Catalac [Catalac 10m preferred for boat, 9m preferred for price]- she needn't sail tight to wind, as winds blow up/down straits in any case in my location and currents are stong. But, she must be made fit to take the beach in river flats that are seldom soft mud. My grounds are tidal- spring tides can be over 20' and docks/marinas are scarce.

Would owners and knowledgeable sailers please weigh in on fitting sacrificial keels to a Catalac? May they reasonably be fit to a Catalac's hulls so that she may take the beach without injury?

I've seen the HT on the hard- no problem affixing any of several possible protective keels on bottom of her short, stout, integral keels. But I've only seen the Catalac in photos [hard to find a boat on west side USA]. She does not have keels- so protection must adhere to the hulls themselves. Yet, being a British boat, seems likely she's 'beach-able'- suggestions?

Will she handle the "thuds" of gentle swell as tide eases from under her?
Can protective strips be beefed and affixed to handle a pebbly and/or sandy bottom as well as a muddy one?
Click to expand...

Keels being in effect wings in the water are what allows a boat to go to windward rather than just blow sideways. Since the Catalac doesnt have keels but just motor boat style hulls it tells you how well they go to windward. A pal who owned one for several years confirmed this. An HT is a bit better, and a Prout a bit better still. But they are all motor sailers to windward in any sort of sea - I had a Prout for 7 years and thats certainly what I found.

Last point - the accommodation. OK its nice and big and airy but you cant use all that space. Fill the boat up, take advantage of the room and performance just disappears. Just filling the 50 gal water tanks on my Prout took half a knot off the sailing speed.

That said we took our cat to Spain, felt safe all the time, and enjoyed the floating caravan bit. I would still chose a cat for live aboard / long distance sailing but would not go near one for weekend pottering. If you want a motoring analogy, sailing a small cruising cat is a bit like selling the car and driving round all the time in a campervan.
 
The Catalac is designed to take the ground and I would not alter the underwater shape for reasons mentioned in other posts. Try the boat on the berth for a year or possibly less and see what damage occurs. The 'V' of the keel is considerable and does take abuse. If you think that wear is excessive after a year build the area back up with expoxy and a s/s wear strip stuck in place.
If you alter the hull shape, a Catalac can trip over though I suspect that 25mm of hardwood if used as protection would not make much difference. Please report back on what you do and the results.
 
Thanks to all, very helpful comments, ideas and recommendations-

-BOATHOOK:

Would your recommendation to allow use for a year before deciding to add SS wear strips be unchanged if you knew she would be taking the ground on pebbly flat, with some light pounding/grinding to be expectecd at each tide [given fetch of the bay itself? [I'm not being snide- genuine question please].

I guess the questions are: regular beaching on flats that are not assured to be mud/ soft sand- probably OK?
Most bottoms in flats here are almost assured to include "pebbles" [at least] within an anchor swing wide/long enough to allow for 25' tide at full [even with spring line anchors].

As you wrote, I would not expect to add more than 25mm strip if used stainless steel
Of course, would prefer not to go to the trouble at all if forum considered such strips unnecessary, given the lay-up of the Catalac, but glass is glass and wear seems unavoidale- most important question of all, then- and I think it's been answered here, but asking again for confirmation:
Is adding these strips a reasonable project even considering the steep "V" of the keel.
One member here emphasized the difficulty while another member described his approach adding SS pieces.

-BIRDSEYE-
re: your analogy of Catalac to a caravan.
This is about what I had thought, thanks for confirming- well put: caravan= Catalac; day travel, you want something different. Catalac, considering my grounds, type of sailing and purposes, I think will suit, with a dory nearby for day to day 'get-around'.

Gentlemen never sail to windward, of course, but especially to windward and against strong current. Concern would be having enough engine power to keep her head up when crossing a bar...so adequate engine power is more of a criterion for my intended use than is windward performance.
 
Apologies for reope ing an old thread but I just bought a Catalac 9m and found your thread discussing my exact question.

I wondered if you ever fitted anything to yours? My boat is on the hard and the previous owner has ground down the keels ready to work on them so I guess I'm In the ideal position to make changes.
 
yohanfunk said:
Apologies for reope ing an old thread but I just bought a Catalac 9m and found your thread discussing my exact question.

I wondered if you ever fitted anything to yours? My boat is on the hard and the previous owner has ground down the keels ready to work on them so I guess I'm In the ideal position to make changes.
Click to expand...

I would try to find out why the previous owner ground down the keels. I wouldn't alter the under water shape by much as it will effect the safety side of the design and I suspect that insurance companies will want to know and adjust the premium accordingly .....
 
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I have a snapdragon with twin encapsulated keels that probably goes to windward just a little better than the average Catalac but, hey, that's what the donk's for...

When I got her, she had 35 year's worth of damage from grounding on the keels, so I got some fairly coarse glass cloth and epoxied three or four layers across the bottoms of the keels and up the sides a little way. This has resisted all my efforts to cause further damage drying out (mostly intentionally) on various surfaces. As my wife is finding moving around on a tippy boat with an awkward companionway more and more difficult, we're considering a Catalac and, if we do get one, should there be any signs of wear on the one we buy, I'll do exactly the same.
 
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