Warren's Build Log, CAN 573

[Warren Nethercote]

It seems easier to embed a log in the forum rather than to become proficient at Weebly, or some other vehicle. It is how more forums (fora?) handle this matter in any event. To date I have made a few posts in other strings, and over the next couple of days I will consolidate them here.

Until recently I had a Soling, which I liked, but I had to keep it afloat and became increasingly concerned over going away on judging gigs during August and September - the Atlantic hurricane season. I am an International Judge, so I spend more time driving judge boats than soft-water sailing. Winter is now my key sailing season, in DNs, but I still would like to have a soft-water boat. The i550, being a trailer sailor, gets around my home club's lack of a crane, and the local marina's outrageous travel lift charges. Sailing with a crew of two has advantages too, and a number of club members have expressed enthusiasm for crewing on a little plywood rocket. The i550 also lets me build something - I've built three DNs in the past four years. But this project will be slower due to other projects: I will initially focus on 'bits' and not do the hull until next winter.

I have a place to build, since the Soling will no longer occupy my workshop/boat barn in winter. The photo is an old one, from the summer of 2001 I think, but it does show that I won't have to kick the car out into the snow for my build. (edit: and since that photo the double line of incandescents in the boat barn has been replaced by a nice array of fluorescents.)

[Warren Nethercote]

Like many I am starting my build around the edges .....

I drew up a ballast bulb based on Chad's beavertail bulb, using old-fashioned technology: even a planimeter to determine bulb volume and weight. I drew waterlines to allow traditional sandwich construction in pine, and assembled the pattern in top and bottom portions to allow assembly on a parting board.

A driveway foundry is not for me. Today I delivered the pattern to Tern Boatworks, based a Gold river Marina, who will pour the bulb for me the next time they do a foundry run. Their usual products are bronze or aluminum, but they do the odd lead casting. On the way out of the yard I spied an interesting throw-back: it is apparent that not everyone is sold on light displacement ratio!

I've got some winter preparation to do for DN sailing (a new runner plank, a couple of runners, and a new steering post), after which I will make a start on the foils and cassettes.

[admin]

This is great, Warren, and if I can still remember how to deal with HTML, I'll add this thread as one of the "blogs" on the class Blog List.

I envy your workspace!

[Warren Nethercote]

Perhaps I should say what I would like to build and how ...

In terms of general arrangement, I can’t say I am enthusiastic about the i550 coach roof. I have slept on a few destroyers, a research ship, a dredge, a square-rigger and some cruising boats. The ships were OK, despite the aroma of Diesel, because I was paid to be there. I can’t get enthusiastic about choosing to sleep on a small boat anytime soon based on past experience on motorboats or sailboats under 40 ft, and 5.5M is SMALL. So my inclination is to build the PDX-style cambered foredeck, with enough crown to keep the class rules happy. The alternative might be to substitute a very low coach-roof for the present one, although doing so would be more labour-intensive than a heavily-cambered foredeck.

The benefit of a low coach roof is indirect. I like Chad’s continuous stringers (they make my naval architect’s heart warm) and full-height longitudinal webs under the cockpit. I have Chad’s pdf’s and could build with a coach roof without having to modify any of Chad’s drawings: when I was a working nav arch we worked with pencil and paper, and sometimes even ink, rather than CAD, with which I have little experience beyond printing drawings. But I am the first to admit that reluctance to modify a drawing is a poor basis for a design decision.

In any event, I am rather partial to rolled side-decks which would require drawing mods. There are a number of examples already, most using wood strips or foam for the curved bits, but the most attractive to me use bending plywood available from Boulter Plywood in Boston. I have bought some previously for use in iceboats: it is nice to work with and not all that expensive, until you factor in cross-border shipping. Tim Ford’s boat is one example of use of bending plywood, while another builder’s unfinished hull (apologies for source forgotten) is a more extreme example reminiscent of a 505, just about the most attractive dinghy ever designed in my mind. Whether appearance can overcome pragmatism and the attractions of a quick, simple straight-from-plans build remains to be seen.

Having said that I like Chad’s continuous stringers, I would need to use his building technique (installing interior structure before the hull sides) or build the boat upside-down, in the traditional manner. Time will tell.

As an aside, the PDX deck or a lower coach roof will reduce the fore-triangle height unless the mast length below the gooseneck is increased. No big deal if you plan for it, either as a longer spar or a smaller jib and asymmetric spinnaker.

I would like to launch my spinnaker from a ‘sock’ and envision a permanent opening in the foredeck feeding into an under-deck trough, open to the cockpit. The sock, pre-loaded with the spinnaker, would slide into the trough before sailing. The trough’s sides could be sealed to the deck and be open to the cockpit so that scooped-up water would drain into the cockpit rather than down below. I think this is feasible, and I wouldn’t miss the space consumed by the trough since my cabin will be used for little more than storage.

I am undecided about the prod: fixed or slewing? Fixed is simpler, and can be arranged to drain leakage into the cockpit. I sail in an area of reliable sea breezes, so I am not concerned about getting deep enough in light air, but I sail in a mostly symmetric chute PHRF fleet, so maybe a slewing prod may be wiser. A slewing prod may conflict with my under deck spinnaker trough, although careful layout might overcome this issue. Since I am delaying hull construction I will have time to think about it.

Finally, I have bitten the bullet and will go the carbon rig route, and am leaning towards synthetic rope standing rigging rather than wire. If nothing else it should make trailer-sailing less aggravating: there is nothing worse than fighting with a bunch of recalcitrant wires – it was the worst aspect of getting my Soling ready for the road.

In time we will see the strength of my convictions.

[admin]

Great stuff, hope you keep on with the project, Warren. I added this thread in the BLOGS section of this site.

In defense of cabins: once I get the hardware sorted and the boat is proven to be durable enough, I would like to do some of the short distance races on here on the bay. These are usually no more than 20-25 nm and in somewhat sheltered waters. I can't imagine not having a cabin. 4P and 5P safety requirements under PHRF here require a fairly significant amount of gear and I hate blindly rifling through a bunch of stowed items in a dark locker or a small below-decks storage space. I like being able to step below and sit down to take off boots and foulies in relatively drier environs. If you are just doing daylight W/L races or short RLC courses, I could see eliminating the house. But for distance, I need a place to put a cooler, two gear bags with foulies, tools, the battery (mine is electric O/B) and then all the necessary sundry safety items. If I want to lie down and take a nap, there's even that.

So, horses for courses and all that, but I still like the original design concept for the Aussie coastal racing intentions.

[ryderp]

On another note, having a cabin or not doesn't have and effect on the height of the mast which (as I recall) is set from the bottom of the hull. The current "class" rules allow for the longer mains like the PDX boats, or the shorter mains of the traditional "class" boats. The difference is the height of the boom. I went with the higher boom because I like not having to get on my knees on every gybe.

I'll second the sentiment about having a normal height cabin. I can sit down there like a human being when I'm working on stuff, stowing or retrieving sails, etc. Chad's short cabin is my second favorite arrangement (it looks very nice). I've never been a fan of heavily cambered foredecks, but of course others (like thousands of J24 sailers) would disagree.

[Warren Nethercote]

Ironically I also am no lover of heavily cambered decks as working spaces. My two seasons of regularly crewing on a J24 are memories of nothing but discomfort. Those old enough to remember the home-built j24 prototype may recall that the designer/builder chose the deck configuration for no other reason than to simplify and speed the build. Hopefully one never goes on the foredeck of a small asymmetric boat when things are going well.

At my home club racing is typically round the buoys stuff, albeit with 8 to 10 mile course length so I am not contemplating any point-to-point races where a coach roof might be welcome.

The mast dimensions are indeed taken from the keel in the class rules, but if one bought a 'stock' mast from CTech I imagine it would be sized for a coach roof. From what I can deduce from the PDX pictures they may have done just that - but that is speculation.

And thank you to Admin (Tim?) for the link on build logs.

[i550sailor@aol.com]

Great stuff, hope you keep on with the project, Warren. I added this thread in the BLOGS section of this site.

In defense of cabins: once I get the hardware sorted and the boat is proven to be durable enough, I would like to do some of the short distance races on here on the bay. These are usually no more than 20-25 nm and in somewhat sheltered waters. I can't imagine not having a cabin. 4P and 5P safety requirements under PHRF here require a fairly significant amount of gear and I hate blindly rifling through a bunch of stowed items in a dark locker or a small below-decks storage space. I like being able to step below and sit down to take off boots and foulies in relatively drier environs. If you are just doing daylight W/L races or short RLC courses, I could see eliminating the house. But for distance, I need a place to put a cooler, two gear bags with foulies, tools, the battery (mine is electric O/B) and then all the necessary sundry safety items. If I want to lie down and take a nap, there's even that.

So, horses for courses and all that, but I still like the original design concept for the Aussie coastal racing intentions.

I am also for the cabin version and spent a couple hours last night riding out a rainstorm in mine. I have now spent two nights on the boat, and think it was fun. I did a flat floor in mine instead of bunks it creates 3 flotation chambers between 18/53.5, 53.5/89, 89/110, It gives positive flotation, but also gives you a really nice cabin floor.

[Warren Nethercote]

I do seem to be in the minority here when it comes to coach roofs!

i550sailor (sorry for using the handle, but I am too new to associate it with a name, or more important, a sail number/build log), for the odd night afloat or a retreat from the rain your continuous berth flat looks to be better than traditional; berths, as are the storage bags against the hull sides. I am sure I remember seeing your slewing prod arrangement in one of the build logs - but which one? Have you had much experience in a slop yet? Assuming that your compartment between the stem and the first frame drains overboard, are the drains adequate? The one disadvantage of the continuous berth flat is that any water getting over the dam created by the first frame will wet the entire berth flat after the first tack, but that may be a rare occurrence.

[admin]

Definitely build the boat that best suits your usage style, Warren. We were just trying to justify in our own heads why we built ours.

I ilke that storage bag i550sailor!

I think I am in my 11th year of racing J24s at least once a week. If there's a more uncomfortable boat to hike on, I can't think of it...maybe a Thistle or a 210. But the biggest issue with regard to comfort on the 24 is the lifelines as defined by the Class Rules. Since the i550 won't have to deal with those, it should be a much more comfortable ride, and I reckon the shrouds would serve as enough of a handhold in an inadvertant, sudden heel to weather.

[i550sailor@aol.com]

I do seem to be in the minority here when it comes to coach roofs!

i550sailor (sorry for using the handle, but I am too new to associate it with a name, or more important, a sail number/build log), for the odd night afloat or a retreat from the rain your continuous berth flat looks to be better than traditional; berths, as are the storage bags against the hull sides. I am sure I remember seeing your slewing prod arrangement in one of the build logs - but which one? Have you had much experience in a slop yet? Assuming that your compartment between the stem and the first frame drains overboard, are the drains adequate? The one disadvantage of the continuous berth flat is that any water getting over the dam created by the first frame will wet the entire berth flat after the first tack, but that may be a rare occurrence.

Hi Warren,

I am Mark Stieber, builder of i550 #505 in Colorado. Nice to have you in the fleet (you have an impressive sail resume) I hope we get to sail against each other.

I did storage bags on both sides, which keeps items stored nicely, these boats will rock, side to side in a breeze,( I have found more wind,,,, the better)

The articulating sprit is the way to go in my opinion (apx 23 degrees). I am draining mine similar to the PDX boats, a shelf/gutter with a hole out the side, so far, after 8+ races the boat has been dry. (i will say the advantage of the continuos berth flat is that you can sponge up any water "directly between frame 110 and 124" although I have only had to do it once, after the water was white capping,,, the ride was awesome.

[Warren Nethercote]

Thanks Mark. Waves are the norm for my home club, so clearing water leakage through the sprit hole is of interest; regardless, I had not considered that any spillove would find its way aft of 110. While the berth flat may get wet, it won't be a swimming pool!

[i550sailor@aol.com]

it was like someone had dropped their water bottle. Andrew Clauson suggested putting a cap on the end of the pole.
My cabin sole is flat and steps down between 110 and 124, 124 is solid with only a cut out for the 4" screw in port hole, making the entire back of the boat a flotation chamber. So no, not a swimming pool at all.

[Warren Nethercote]

A neoprene disc might do the job .... Chad's puck or a variant thereof might alSo reduce water ingress.

[Warren Nethercote]

In another string Jon asked of progress. I replied in part: "No build progress photos because any progress is remote at the moment. I had a call from the foundryman a couple of weeks ago: he was getting to my bulb and had a couple of questions, like "Did you include a shrinkage allowance in your pattern?" I said "No, but it won't matter in this application ...." So I should see a bulb one of these days - probably later rather than sooner. On the rig side we have selected prod and boom designs from available tooling and mast tooling is under construction at Fast Composites (aka Phil's Foils). The plan is for February delivery of mast, boom and prod so I can pick them up in Ottawa while returning from the DN North American championships. With the Canadian dollar sliding I am happy to have chosen a Canadian source.

I have some iceboat-related composite stuff to do (a new CF tiller) and will likely use that as an opportunity to start working on the i550 foils."

[Warren Nethercote]

In the spirit of "there is no progress without photographs" here is a picture of my raw boom tube. Edit: Please pardon the sideways photo!

[Warren Nethercote]

At this stage I should be calling this my 'buy log'. I stopped by Competition Composites on my way home from the DN North Americans in Madison (7000 km of driving was more than compensated by a great regatta). After some thought on how to transport the mast, which was NOT in sections we built a box that overhung the ends of the truck by 4 feet or so. More useful pictures after I make if home tomorrow: after all, who cares about a plywood box? I do have a picture of the mast and boom but the file is too big for polite forum posting - I must install the photo reducer on my travelling computer.

[Chad]

Here's Phil's page on Warren's spars:
http://www.fastcomposites.ca/site/marin ... -a-z/i550/

Some good looking stuff!

[admin]

Wow, pretty slick! I may have to solicit a rudder and cassette from Phils after I blast mine to smithereens this coming summer.

--Mr. Optimisitic

[jray]

I had Phil build my rudder/cassette and strut. Top quality

[Warren Nethercote]

Speaking of rudders .... making shavings. Ten inch chord at the top, with the lower part of the span tapering to 8 3/8 inch chord. At this point the Western Red Cedar core is too long, allowing for easier clamping to the bench.

Just using the NACA 0012 section, lifting templates directly from the pdf plans by printing them at appropriate magnification, gluing them to 3mm Okume and cutting them out. Nothing special.

[jray]

Very nice Warren, love the hand plane. I used them a lot in my build with great success. Are you planning on laying up some carbon on the sides before glassing? If it remember correctly either Andrew, TTB or Josh, Shazza had issues with just wood layup flexing to much and had to redo laying unidirectional carbon to stiffen it up. Only mentioning as it may be easier now then later.

[Warren Nethercote]

Jon,

My hand-tools tend to be in better shape than my machine tools. I started routing groves for the leading edge, but the depth adjustment on my router was too crude. I switched to the table saw for the trailing edge, but my outfeed table is pretty nasty. I was much more confident, and less stressed making shavings with a really sharp plane. Not to mention less red cedar sawdust.

I am not planning on the Gougeon 'trough' with carbon fibre in it for the rudder, although I will do so for the keel, but I will lay up a carbon fiber skin instead of glass on the rudder. In the Gougeon approach (CF in a trough followed by a full glass skin) I am not sure that the glass skin does much except keep the water out. Most of the builds here have used the Gougeon approach for the keel, but have used carbon fibre for the skin as well.

At the moment, for my rudder I am thinking in terms of a full-span CF sock followed by a layer of 12 oz uni-directional CF from the top to about 2/3rds span and then a second layer of 12oz unidirectional CF, full span. The carbon fibre is en route from Composites Canada (Toronto). I need to troll the build logs to see what skin schedules people have used for cedar core rudders, but intuitively, 24 oz of CF, plus a CF sock for some cross-grain reinforcement seems fine to me based on what I have done with iceboat runners. Apples and oranges I know, but both applications are stiffness driven. If the build logs show my planned CF schedule to be 'light' I will have enough CF on hand to do more, and must do so before building the cassette of course.

[Chad]

I'd suggest one more layer of uni, even if it only goes to the 1/3 span. Bending loads near the lower gudgeon are pretty big! Numbers for your foil, based on 10" chord and 1.2" core (wood) thickness, roughly 48" immersion, here:

https://docs.google.com/spreadsheets/d/ ... edit#gid=0

(note this is a publicly tweak-able file, so the numbers may change later)

[Warren Nethercote]

Thanks Chad. I will follow your recommendation. So:

- first a full length knitted CF tube
- then an approx. 20 inch (let's say 24) length12 oz uni CF
- then an approx. 42 inch length 12 oz uni CF, and finally,
- a full length 12 uni CF

Oddly enough that is the same layup that I use on my DN runner bodies, albeit full-length for everything! The runner body cores are Baltic birch plywood, largely for transverse compressive strength.