420: Lagoon 420 Stretch ? Turbo Charging ?

[Mark424]

The Catana performance & stretch FastCat threads make me wonder what are the options for turbo charging a cruising cat. Say the L420 (or some other model) has enough space for you, but you are looking for more performance. Moving up to a larger model won't necessarily get you the performance you are looking for and is likely to cost a lot more money. A number of people have stretched their Seawinds (Hull Extension, Welcome to Siudzinski KatieKat), I also saw a stretched Privilege 43 in Tampa last year.

My questions isn't limited to the L420, but there is a lot of discussion about the L420 v L440, last I checked the L420 was heavier and less expensive than the L440. Could you use the difference in $ for a screecher and hull extensions? is that a waste of money? Would you have to do both bow and stern, would stern only screw up the balance? I believe Outremer is the only one that offers basically the same boat with a variety of hull lengths and performance packages.

[Jeannius]

Privilege always stretched their boats it just wasn't reflected in the model numbers.
Most Privilege 435, mine included, are actually 44 ft and a few inches as they have the 'Easy Cruise' option which includes a 10 inch extension at the stern.

The present 445 designation reflects the fact that the hull without the extension is no longer an option. The present 495 is the previous 465 with the 3 ft Easy Cruise extension.

[Nordic cat]

I have seiously considered this for my Tobago 35, she could do with a metre extension aft, and maybe a bit at the front as well.
After upgrading to the 18 hp engines, and adding a couple of batteries, she drags her transom.

I have hull number 1, and can see where they originally had the waterline, which is about 2 inches higher up at the stern. So someone didn't have their weight calculations right from the beginning.

When I add a small rib and outboard to the davits, the transoms are submerged by about 30 mms at the dock.

The cost for the extension will be around 20 kUSD.

I saw a 32 ft. Maldives that was extended a metre, and it looked good.

While I sit on the fence on the hull extension, I have been fiddling with other "turbo-charging" options.

1.) Added a bowsprit and necessary reinforcements to fly a Code 0 and an Asymmetric.
2.) An outleader kite sail
3.) A new, 1 m taller rotating wingmast with a big flat top mainsail, and a new larger selftacking jib. Composite rigging. This is a work in progress, and will be delivered in 3-4 weeks.

The original rig limits the size of the jib as there is a protrusion at the forward end of the mast. Removing this will give me a slightly larger jib.

It will be interesting to see what increase in performance this will give. I think the hull extension will give me better value for money from a performance/$. Theoretically an extension of waterline length from 38 to 38 ft will give me 0.3 knots of "hullspeed), but if i can get a clean exit at the transom and bring down drag, it could easily be more.

I will document all this later on, for future reference.

My experiences with this and a previous boat are what led me to extending my new design. I started of at around 43-44 ft, now she is 49 but I haven't changed beam or anything else.

Waterline length is the key factor IMHO

Regards

Alan

[cat man do]

I've done a few step jobs/extension on my own and others boats, it always makes a vast difference.

I've even seen 32 foot cats chopped in the midlle (just behind daggerboard case, all the way across) and had a few feet dropped in and some added on the back to make full bridgedeck cruser/racer

Seen million dollar cats get bows chopped and lengthened, every one made a definite improvement, and IF you can do the work, not that hard or expensive.

The cutting and destruction is good fun.

(pics of a 60 footer one of my mates took the saw to)

Dave

[northerncat]

i just cant fathom the extra tedious work cutting it in the middle would cause, bow extensions can look funny if not done right but a stern extension woulodnt be too hard
sean

[catty]

Adding transom extensions generally only cleans up the water flow . You're adding weight just where you don't want it and little of it is actually in the water providing buoyancy.

Adding it in the middle has the most positive outcomes as it is actually adding buoyancy and increasing the hull length beam ratio and adding accommodation space that you can now fill with more useless crap.

I know of a few mono's both steel and plank on edge that have had this treatment. Both successful.

[cat man do]

Originally Posted by catty

Adding transom extensions generally only cleans up the water flow . You're adding weight just where you don't want it and little of it is actually in the water providing buoyancy.

.

Without getting to catty I have to disagree.

When the boat is sailing the hull is pressed adding waterline length and bouyancy.

I have done several succcessful ones (and no duds) where the dinghy is now carried without dragging the bum and the boat has increased waterline length adding to performance.
My boat had a totaly new lease of life after the extension and I added an enclosed bridgedeck as well.

Minimul weight was added compared to the increase in bouyancy

Dave

[Factor]

Yep Dave I agree. Almost every multihull I have seen with a transom extension has benefited from it. They can be quite light and as you say add length and buoyancy when pressed. Seawind for example tested what some owners had done to the 1000 and did their own extension. As with most things in life all you can do is judge the evidence and the evidence is clear on what I have seen, happy to hear any direct evidence to the contrary.

Some of the best boats I have seen have started with the premise - build a 38 foot boat but put it on 50 foot hulls, eg the outremer is a reasonable example of this.

[Mark424]

So it sounds like a modest transom extension can be good. Any ideas on (a) the cost for say 4-5' on 40-45' cruising cat, Lagoon, FP, Priv, etc. (b) At what point do you need to to get a naval architect involved and look at extended the bow as well or tweaking the sailplan? Per the previous post if you are putting 10' on a 38' boat that would probably by a whole different operation.

[sailvi767]

It would make no sense to buy a new boat with the intent to lengthen the boat. The costs would be way to high. You should look for and find the boat you want. There are a large variety of boats available these days. Many manufacturers have over time made hull changes. The Voyage 440 is a example. It was the Norsman 430. The hulls were split and made wider as well as adding a foot in length. The result was the Voyage 440. With a desire to have a genset and ac on more and more boats Voyage made another change and lengthed the boat again to 45 feet calling it the 440 plus. The extra length is all in the bows and resulted in a boat that could better carry the weight of a genset forward and also pointed higher and had more sail area with the foresay attach point moved forward. The Leopard 4200/4300 and 4500/4700 were also boats that had hulls length added. In those cases the extra length was added to the sugar scoops. Again however it would not be cost effective or make sense to take a 4200 or 4500 and add length. Cheaper just to buy a 4300 or 4700.

[cat man do]

Originally Posted by Factor

Some of the best boats I have seen have started with the premise - build a 38 foot boat but put it on 50 foot hulls, eg the outremer is a reasonable example of this.

Same with my current build

It is a 40ft Accom and storage on 50 ft hulls.

Dave

[cat man do]

Originally Posted by sailvi767

It would make no sense to buy a new boat with the intent to lengthen the boat. The costs would be way to high. You should look for and find the boat you want. .

Transom jobs are not to bad

Hull Extension

especially if you can do the work yourself

On my last boat I did a step job and a cabin in the guts, admitidly it was on a 30 footer, not a 40 footer but it would have cost me less than $1500 in material to do.

[Mark424]

Originally Posted by sailvi767

It would make no sense to buy a new boat with the intent to lengthen the boat. The costs would be way to high. You should look for and find the boat you want. There are a large variety of boats available these days. Many manufacturers have over time made hull changes. The Voyage 440 is a example. It was the Norsman 430. The hulls were split and made wider as well as adding a foot in length. The result was the Voyage 440. With a desire to have a genset and ac on more and more boats Voyage made another change and lengthed the boat again to 45 feet calling it the 440 plus. The extra length is all in the bows and resulted in a boat that could better carry the weight of a genset forward and also pointed higher and had more sail area with the foresay attach point moved forward. The Leopard 4200/4300 and 4500/4700 were also boats that had hulls length added. In those cases the extra length was added to the sugar scoops. Again however it would not be cost effective or make sense to take a 4200 or 4500 and add length. Cheaper just to buy a 4300 or 4700.

While I appreciate your adivce, I'd really like to see the data to back this up. (a) "costs would be way to high", what are some examples of the costs and what makes you say they are too high? CatManDo, gives one example, however I neither have the time or skills to do this myself (right now anyway). I'm sure the prices vary by 2x from West coast, east coast, to Carribean, but a ballpark would be nice. Many many people have extended the Seawinds and Mantas as one example. (b) I'm not sure you get my point, I'm not interested in wider hulls, more space, etc. If I can find the accomodation plan, features, quality, etc I'm looking for, but desire more performance (one factor of which is lower D/L) the only way to do that is to mod the boat. If I decided I liked the 4200, most of differential dollar used to buy the 4700 would be for things I didn't need/want and I'd only marginally improve performance. I'm not after a rocket sled, but would like medium accomodations with an ability sail/motorsail consistently in the 7-10 knot range in light to medium air, preferably 8kn + if I can afford it. Most cats will git up and go 10+ if you throw enough wind at them, but many days winds are 5-15.

I do appreciate the feedback, just need a few more details to be convinced.

[sailvi767]

The 4300 is the lengthed version of the 4200. The 4700 is the lengthed version of the 4500. They are 4200/4300 is a entirely different boat and design then the 4500/4700. I will say that I think the sugar scoop arrangement on the Lagoon 420 borders on dangerous. I would certainly never consider the boat if I did any diving at all. If you could lengthen the scoops about 4 feet and make the steps larger and less steep it would be a huge improvement. It would however add weight to a already heavy boat without adding sail area. I also think it would be very expensive. Its to bad that Lagoon did not offer the 440 with the helm station down and a larger mainsail with a lower boom plus a two foot transom extension. It might have been my first choice in a boat.

[cat man do]

Originally Posted by sailvi767

It would however add weight to a already heavy boat without adding sail area..

Only heavy if you used ridiculously heavy layups like the rest of the boat.

I have worked on steps for a 40 footer that I think added more pounds of bouyancy than the steps weighed.

This was done by using 20mm foam , 200gsm Kevlar and 400gsm glass on the outside and 200gsm kevlar on the inside with epoxy.

I doubt these steps would have weighed any more than 20kg/side.

They took about 4 weeks at a leisurly pace to do, so probably 2.5 weeks going hard.

That same boat then went on to win the "Brisbane to Gladsone Multihull Race" about 350 NM ocean race

(additions aft of pink line)

Dave