Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 03-10-2015, 22:33   #1
Registered User

Join Date: Oct 2015
Location: Phoenix, AZ USA
Boat: DIY Trimaran using 16' Apollo and 18' Prindle
Posts: 6
Daysail trimaran from parts

My goal is to have a safe / seaworthy daysailing trimaran to use locally in Phoenix, Az; primarily on Tempe town lake which has a mast height restriction of 30'. I already have a 16' AMF / Alcort Apollo sloop and recently procured an 18' Prindle catamaran within the last couple of months. I've removed all hardware from both boats and test fit the apollo on the prindle trailer with the prindle hulls along side. They fit albeit without any room to spare. The deck height is equal as they sit on the trailer now which would be ideal for straight tubular akas. The keel of the prindle / amas is about 6-8' deeper; this is primarily why I'm asking for advice.

I've noticed that there are many variations in hull configurations but primarily slender vakas, equal in length to the amas. The keel of the amas is usually more shallow than the main hull. My concept is far from the "standard" with the round "tub" shaped keel of the Apollo and the massive (in comparision to main hull) amas. My primary concern before I start fitting the akas, is the waterline and draft of the amas compared to the main hull. I certainly don't want the main hull to be completely suspeneded above the water. The hull wieght of the Apollo is ~300lbs, Prindle is <400lbs. The Prindle mast will be used but chopped about two feet at the top (the mast is damaged). I'd estimate the total wieght when completed to be ~850-950lbs. The akas will be made with 3" OD aluminum tubing and wiegh ~40lbs.

I'd like everyone to tell me that it is fine in this config so the akas are easy to fit but if the amas need to have at a more similar keel depth I can raise them.

Here is a reasonably acurate drawing of the Apollo / Prindle concept.

The next diagram illustrates the keel difference at equal deck height.
Attached Thumbnails
Click image for larger version

Name:	There is no Tri.jpg
Views:	89
Size:	358.0 KB
ID:	110444   Click image for larger version

Name:	There is no Tri but.png
Views:	82
Size:	11.2 KB
ID:	110445  

__________________

__________________
TriJody is offline   Reply With Quote
Old 03-10-2015, 22:54   #2
Registered User

Join Date: Oct 2015
Location: Phoenix, AZ USA
Boat: DIY Trimaran using 16' Apollo and 18' Prindle
Posts: 6
Re: Daysail trimaran from parts

The most similar production boat I have found is the Weta trimaran. I plan on using similar design for the aka for simplicity rather than folding or telescoping.

Some other questions I have:

How much beam is enough / too much? If the beam is such that use of premanufactured albeit used trampolines (perhaps from a Prindle 18) could be used, this would be fantastic.

Should I elongate the stern to equal lenght as the amas, perhaps with a suger scoop?

Should I shorten the amas to equal length of the apollo stern instead?

How much spirit is reasonable?

Should linkage be made to utilize the prindle rudders as well as the Apollo rudder?

I had planned on fix-steping the Prindle mast rather than rotating for simplicity. I assume the Prindle standing rigging is adequate.

Tempe town lake is most often like glass, at speed I hope it will plane without to much effort; will the massive amas and all that boyancy hinder efforts at all?

The Apollo mast has internal hallyards and sheave box exits, the Prindle does not. I could though. Should I?
__________________

__________________
TriJody is offline   Reply With Quote
Old 03-10-2015, 23:04   #3
Registered User

Join Date: Oct 2015
Location: Phoenix, AZ USA
Boat: DIY Trimaran using 16' Apollo and 18' Prindle
Posts: 6
Re: Daysail trimaran from parts

My tentative plans are to have her sailing by spring 2016. It's not just the trimaran refit, both hulls are old and need fiberglass repair as well as modification and paint.
Attached Thumbnails
Click image for larger version

Name:	01515_91XG2riJ0mv_600x450.jpg
Views:	88
Size:	54.0 KB
ID:	110446   Click image for larger version

Name:	img_7554.jpg
Views:	77
Size:	379.6 KB
ID:	110447  

__________________
TriJody is offline   Reply With Quote
Old 04-10-2015, 01:23   #4
Marine Service Provider

Join Date: May 2012
Location: New Orleans
Boat: We have a problem... A serious addiction issue.
Posts: 3,940
Re: Daysail trimaran from parts

TriJody,

I honestly think this is a really bad idea. You are taking two nice boats and going to cut them apart and rebuild one very under designed result.

Just as an example, the crossbeam should are suggesting sound grossly under strength. My A-Cat which weights all of 150lbs uses 3.5" carbon tubes as main beams. Your RM is going to far exceed mine, and so your beams need to be substantially stronger.

I have no idea how you are going to mount the beams to the Apollo strongly enough to keep them from ripping the boat in half.

As for adding a sprint... I have serious doubt that there is enough reserve strength in the fiberglass of the Apollo to handle the loads. How to work around this I couldn't begin to guess.

Finally, the result is going to be incredibly heavy, lack sail area, and be a structural nightmare.


If you really want to go this route, then I would seriously suggest you go to boatdesign.net and ask there. If you are lucky Richard Woods will jump and and may resolve some of the issues I can only raise.
__________________
Greg

- If animals weren't meant to be eaten then they wouldn't be made of food.
Stumble is offline   Reply With Quote
Old 04-10-2015, 01:57   #5
Registered User

Join Date: Oct 2015
Location: Phoenix, AZ USA
Boat: DIY Trimaran using 16' Apollo and 18' Prindle
Posts: 6
Re: Daysail trimaran from parts

Quote:
Originally Posted by Stumble View Post

I honestly think this is a really bad idea. You are taking two nice boats and going to cut them apart and rebuild one very under designed result.
Both boats were built in the 70's. The Apollo is delaminating 3'x 2" on deck, price was $550. The Prindle has soft spots and was purchased for $400. Both are far from "nice."
Quote:
Originally Posted by Stumble View Post
I have no idea how you are going to mount the beams to the Apollo strongly enough to keep them from ripping the boat in half.
Both boats need repair and reinforcement with Epoxy layup and foam core where applicable. Aluminum backing plates in needed areas
Quote:
Originally Posted by Stumble View Post
As for adding a sprint... I have serious doubt that there is enough reserve strength in the fiberglass of the Apollo to handle the loads. How to work around this I couldn't begin to guess.
A new deck will be made using epoxy and foam core for the spirit.
Quote:
Originally Posted by Stumble View Post
Finally, the result is going to be incredibly heavy, lack sail area, and be a structural nightmare.
~950lbs is too heavy to lift out of the beach. The sail area of the prindle is quite big. The reason for advice seeking is to sort nightmares before I commence.
Quote:
Originally Posted by Stumble View Post
If you really want to go this route, then I would seriously suggest you go to boatdesign.net and ask there. If you are lucky Richard Woods will jump and and may resolve some of the issues I can only raise.
Excellent suggestion, there are many knowledgeable sailors, riggers and builders here as well though.
__________________
TriJody is offline   Reply With Quote
Old 04-10-2015, 02:07   #6
Registered User

Join Date: Oct 2015
Location: Phoenix, AZ USA
Boat: DIY Trimaran using 16' Apollo and 18' Prindle
Posts: 6
Re: Daysail trimaran from parts

I probably won't be documenting the build process because of the time and effort it takes. I have one small request to make of you fine members who voice opinion. Please limit the verbal keelhauling to one or two unconstructive criticisms. Thank you.
__________________
TriJody is offline   Reply With Quote
Old 04-10-2015, 10:12   #7
Registered User
 
Cadence's Avatar

Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 6,057
Re: Daysail trimaran from parts

Quote:
Originally Posted by TriJody View Post
I probably won't be documenting the build process because of the time and effort it takes. I have one small request to make of you fine members who voice opinion. Please limit the verbal keelhauling to one or two unconstructive criticisms. Thank you.
This is not a criticism but just something to ponder. It appears from your thumbnail that the amas have more draft and may be suspending your main hull to some degree. If that, is so, will not give you the sailing qualities of a conventional tri and makes the geometry of the loading entirely different on the connecting the three hulls?
__________________
Cadence is offline   Reply With Quote
Old 04-10-2015, 10:21   #8
Marine Service Provider

Join Date: May 2012
Location: New Orleans
Boat: We have a problem... A serious addiction issue.
Posts: 3,940
Re: Daysail trimaran from parts

Fixing the soft spots on the Prindle will take all of two hours. This is a very common beach cat repair. You just drill through the top layer of glass in a pattern around the spot and inject neat epoxy. The problem is not core rot, it's the top layer of skin lifting off. This will rebound the fg/foam. You already have the boat stripped, so a quick paint job, and now it al least looks like a good condition boat.

And I appreciate the plan is to add glass, and epoxy. But how much? And where? How strong do things need to be? I think a much better option is to take the Prindle hulls and use them as the donor hulls for a Strike 20 Strike 20 racing trimaran using a F18 beach cat for hulls and rig . This way you know what you will have when you are done, and the engineering is already done for you.
__________________
Greg

- If animals weren't meant to be eaten then they wouldn't be made of food.
Stumble is offline   Reply With Quote
Old 04-10-2015, 11:08   #9
Registered User

Join Date: Jan 2009
Posts: 141
Re: Daysail trimaran from parts

It's your stuff and your time and money, so if that's what you wanna do; go for it!
Personally, and it's just my opinion, your results will not be satisfying or pleasant to sail. In fact, I think either boat as is will out sail the heavy, draggy, under canvassed boat you are creating. I suggest you rethink the whole idea from a blank sheet perspective.

You have two basically good boats, each designed to do different things.
Option one would be to fix what you have, and then pick the best boat for the day you're out on and the company your sailing with. If you don't like either of them, you can sell them as good running boats and then buy what you really want. Restored and sailing as well known brands, they will have resale value. Either boat should worth a grand in good condition. What you are planning to build will be worthless, market wise.

Option two, if you really want to build something, would be to measure and inventory the parts and rigging you already have $1000 in. Then go shopping for trimaran plans that could make best use of your inventory. I'd be looking for stitch and glue encapsulated plywood (cheap, quick, and easy) or foam/ composite panel plans. You'll wind up with a light, stiff, properly engineered, good sailing boat that you can enjoy. And if you do a reasonable job of it, you'll be able to sell it when you're tired of it.

Personally? If it was me? I'd sell both boats as is and then buy what I really wanted and go sailing.
__________________
dgz3 is offline   Reply With Quote
Old 04-10-2015, 11:29   #10
Registered User

Join Date: Dec 2010
Location: Florida Base, go pretty much anywhere
Posts: 63
Re: Daysail trimaran from parts

I suggest you take a look at the Sea Pearl 21 tri, by Marine concepts. They made two models - one designed to be a trimaran from the mold up, the other a conversion of sorts from the much more common monohull Sea Pearl. Couple of links to check out the concept and how they applied it.
The Versatile Sea Pearl Trimaran
You can Google them and find dozens more.
No profile drawings on the links I reviewed, but the main hull is essentially an old Herreshoff design, flat bottomed, and pretty much like a dory with soft chines. Main hull sits slightly deeper than the amas, so when sailing, it lifts one ama and sails at a very slight degree of heel.
__________________
capnjack.morton is offline   Reply With Quote
Old 04-10-2015, 20:00   #11
Registered User

Join Date: Nov 2012
Posts: 119
Re: Daysail trimaran from parts

If you're going to roughly double the weight, double the wetted surface, add more structure, and use about the same sail area, I would be very surprised if the combined boats weren't a lot slower than either one before you started. I like your out-of-the-box thinking though! I'd look for a well-used Hobie 14, and I'd make the amas sliding/collapsible...tube-slides-into-tube kind of thing...
__________________
rhubstuff is offline   Reply With Quote
Old 05-10-2015, 21:58   #12
Registered User

Join Date: Oct 2015
Location: Phoenix, AZ USA
Boat: DIY Trimaran using 16' Apollo and 18' Prindle
Posts: 6
Re: Daysail trimaran from parts

Thanks to those who offered suggestions.
__________________

__________________
TriJody is offline   Reply With Quote
Reply

Tags
parts, sail, trimaran

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Crew Wanted: Seeking Daysail Crew - Tampa Bay Steven Nicholson Crew Archives 1 22-03-2010 18:01
Daysail Charters in Miami Beach? Connemara Atlantic & the Caribbean 3 10-11-2009 13:31
Daysail in florida second week of march? Thegirlis Atlantic & the Caribbean 0 02-03-2009 11:49
Nice Daysail / Sea Trial of a Hans Chrstian 33 CharlieCobra General Sailing Forum 0 15-09-2008 08:57



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 22:49.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.