Help with Design Modifications

Get on with the build.

Post pictures.

Let us know what you learn.

Cheers!

 

Take a look around the site, tomas. On every thread where someone asks about modifying a design, someone always responds, "Don't." Often it's represented as a redirect, like "Find a set of plans that is exactly what you want," but it's the same thing.

And I am grateful for the feedback. I know that there are many people out there much more experienced than I am in boatbuilding and, being a teacher myself, I know the value of learning from other people's experience.

That is what I have decided to do. I have already begun one, in fact. The only bit I'm worried about is when I get to the sail. I don't sew, and I don't really know how it all works.

For example, the plans I have call for a "spreader" about two-thirds of the way up the mast. I have no idea what it's for or why it's there. I'm a Physics teacher and my father was a mechanical engineer who brought me up working on D-I-Y projects, and yet I can see no value in this "spreader."

upchurchmr, are you talking about the Blue Moon or the Pilgrim? I've switched boats. I see that the Pilgrim would suit my needs better than the Blue Moon, and it has quite detailed plans available. The only modification I can see that I think would improve the speed of the Pilgrim is making a true cutwater at the bow, rather than the flat V-wall bow that the plans present.

I haven't contacted them yet, but the providers of the designs ask to be contacted whenever someone begins construction. I will definitely contact them once I begin the undertaking.

I do intend to finish my dinghy first, though.

 

You mentioned your intent to sail your little boat to Catalina. The Catalina Channel is 20+ miles of open water where the wind often blows 20+kts. Neither of the boats you've mentioned would be comfortable making that trip. You're likely talking about a 5-6+hour crossing. If you intend that going to Catalina is part of your goal I suggest that you find a bigger boat.
Out of curiosity, I'm unclear how your second choice, an unknown boat by an unknown Russian is any better than your first choice, and you've added the complication of translation.
Also it's somewhat startling that you as a Physics teacher and son of mechanical engineer can't figure out why the spreader is necessary.
As mentioned before rather than taking a chance with an unknown design look up designs by Phil Bolger, there are several books. Some of his ideas are unusual but his boats do actually sail and there is an active community for support. Or if you aren't comfortable with that try contacting PAR on this site, he has designs that might suit your need and he is here to offer support

 

Well, that is to be expected whith designs like the first one you posted. If you had a pile of materials for that design you would have been better off building a bonfire than that boat (or any modification of it).

If this is true you should not be teachig physics.

I believe the designer of that boat has been a contributer to this forum in the past. It looks like it could be OK for trips from Long Beach to Catalina, or harbor hopping down the coast (Santa Barbara - Ventura, Ventura - del Rey, Del Rey - Long Beach, Long Beach - Newport, Newport - Dana Point, Dana Point - Oceanside, Oceanside - San Diego). I wouldn't like to be going up the coast so much in it, but that's what a trailer is for.

 

I find it interesting you suggest this course of action.

Have you ever sailed on one of these designs, or talked to anyone who has?

Have you ever watched any of them sailing?

Have you ever seen a video of any of them sailing?

Have you even seen a photo of any of them sailing?

 

I have spent quite a bit of time reading through many threads and you are making a self-serving, skewed generalization. You've missed the point of the many threads here created by others just like yourself that are just starting out and react to advice as negative. I"m not against your efforts and enthusiasm.

When an experienced builder (or especially a consensus by many) tell you "DON'T" it's for specific reasons, not capricious ones to just discourage you. They've gone through the cycles that you are not yet familiar with.

In the end the reality of your building cycles will teach you regardless of what you view as "redirection".
Go and build.

 

Cardboard; The mast is loaded in several directions when under sail. It is both a beam and a column at the same time. Masts need to be kept light in weight. Think polar moments......If they are light they are likely to be bendy. Sometimes you want bend other times not. Mostly not.

Imagine something like a truss. The mast is the upper truss element and the shroud wire is the lower element while the spreader acts as a strut. The spreader helps control mast bend. If the mast bends it will alter the shape of the sail. Experienced sailors tune the shrouds to affect the degree of mast bend or absence of bend. There are times when it is advantageous to flatten the sail. Several techniques work to that end. Outhaul, downhaul, vang, cunningham and mast bend is among them.

Spreaders are sometimes swept aft a little bit in order to place a forward thrust on the mast that we intend to bend. Some masts are rigged with both upper and lower shrouds and some have diamond shaped rigging that obviously includes its own separate spreader.

I suggest that you make some sketches of a beam with applied loads and then sketch in a tension member with struts. You will then gain a better understanding of the function of the spreader/strut scheme.

There is a sailors learning curve that takes some time and experience to conquer. You are at the bottom of the curve. Don't despair. If you really want to be a sailor, the learning part is fun. Meanwhile do not sail farther from the beach than you can swim.

 

Simply Google "Long Micro". Also "Micro, Bolger".

 

Cardboardking,

One of the problems with coming to the forum is more suggestions than you might want.

For a very reasonable price of $96 you could get plans for a Core Sound 20.
http://www.bandbyachtdesigns.com/cs20.htm

This boat is a very well proven design for home builders, has participated and won the Everglades Challenge, is sailable in high winds, reefs from the cockpit so you don't have to go forward of the cabin for any reason, and easy to balance due to the twin masted rig.

If I was ever going to build a monohull this or the other related designs by the same designer would be what I want.

About the spreader. Masts that are supported by stays (wires) can be lighter than unstayed masts. If you use spreaders the stays provide more support in the middle of the mast, so the mast has more capability to take the wind pressure. Sorry - I didn't see Messabouts explanation - it is much more complete.

The alternative is seen in the boat I suggested above. This is an unstayed mast which has the virtue of less parts to break and buy. It also appears to perform pretty well as seen by the Everglades Challenge win. You really ought to look that up. Your Catalina island trip "should" be easy by comparison (should because I have never done it!)

 

No, to all the below.

 

The latest design of mine to launch, occurred just a few months ago and pictures where posted, both on the trailer and underway on this forum (as well as others). Once again Paul B has entered a thread, spewing his brand of disinformation, innuendo or insinuations, with his typical and blatant disregard for offensive and demeaning commentary and his general disdain for everyone, which means this thread is now doomed to be closed, usually after his verbal fist fight with one or more of the other thread contributors. This is his typical method of participation here and I'm at a lose as to why Jeff has permitted it for a decade now. There's not likely a single regular forum member, that hasn't experienced this peculiarity from Paul B. Maybe Allan, Upchurchmr, Messabout, Tomas and the others on this thread can correct me if I'm wrong. Sometimes a boil just needs to be lanced.

 

Yeah, I agree with PAR. Paul B. is a rather negative character. He appears to get enjoyment out of making people miserable.

 

PAR,

I wouldn't disagree with you.
Cardboardking needs this kind of discussion so he can see where an individual comment is coming from. It adds a little balance.

As a person who occasionally has gone a little off the deep end (myself), it also gives the person being commented on a chance to see how his attitude might be affecting others - and do a little self correction. Sometimes that doesn't work.

Additionally I usually cannot tell exactly what Paul is talking about.

 

I agree that some of the proposed changes aren't wise, from a number of angles. I think Cardboard's inexperience in both sailing and understanding hydrodynamics is motivating much of the perceived "improvements". With more sailing experience, he'll develop a better understanding of what type and size of craft he wants to take to Catalina. I wouldn't want to take any of these protected waters craft into that cut of water.

To directly answer Cardboard's concerns, most sailboats are just going to do what they're going to do. Meaning you can push the ends out a bit, screw with the beam, put on a bigger rig, but unless you have a very strong grasp of what you're doing, it's not going to go faster and will likely be slower. On the other hand, if you understand the principles and dynamics involved, you can make improvements to the performance envelop, but for the most part, these will amount o fractions of a knot, which seems insignificant, unless racing another boat exactly like your use to be.

I understand the desire to build, but hull shape changes should be left to those with a bit of experience, particularly when you're farther from shore than you can swim back to. Picture it another way - would you fly in an airplane that was modified from the plans, by someone with your sail design experience?

I think there are lots of plans available that will easily suit your needs. To this end, your first task isn't looking to change things, but to establish a solid SOR and see which design best suits it. The first thing you should do is beg, borrow or maybe steal a boat for the day and cruise out to Catalina. Take a fairly good size boat, so you don't get your butt whipped the first time out. 20' or longer and take an experienced skipper along with you, so you can kill two birds with the same ride.

 

I disagree, I think that a lot of the time PaulB says what needs to be said. Also from what I've read of his posts he seems experienced and technically knowledgeable. Unfortunately there are times when forum posters, including myself, need to be held accountable for what they post, PaulB is willing to do this. Obviously a goal for a forum like this is to help provide accurate information I think PaulB helps with that and read his posts with interest.