Fiberglass bracket questions

[cbboatworks]

Good morning, I am in the process of doing a complete custom rebuild of two 20' seacrafts, one is a 71 and the 0ther is a 74, with building two at the same time it is getting quit expensive, no corners will be cut with the build, however I do want to save a little money somewhere so I am considering building my on outboard brackets, if I can do this I can take that few thousand saved on building my brackets and use it somewhere else in the hulls, I love the hermco brackets and would love to build something similar, does anyone have any measurements plans etc. i will post build pictures of both builds when possible, we have both hulls in the shop under the knife now and will start building brackets in 2 weeks, i want to say thanks to each and every member here for sharing there experiences so all of us who love the lines and ride of the most amazing hulls ever built.. pictures will follow here or in a new build thread...thanks again for any and all help

[JohnC]

There is a thread not far down the list of a member who built one. If I recall he said that the cost was around 1K for materials and there are a lot of hours involved too. I can build most anything but I am not a great fiberglass fabricator - this will be largely a learning experience for me. I would love to build a bracket just because I want to make one myself but the bracket is probably the most structurally stressed part on a boat (on par with the transom). In my opinion, proper engineering/design and good workmanship are very relevant when it comes to a bracket build. I too am building a 20 and I will go with the Hermco when it is time. He has done several and the reports I have seen from people who have used them are very favorable. The difference in cost is not as much as I thought it would be at first glance and the time factor becomes very valuable when I think of all of the other things on my boat that I need to work on. I see by your forum name that you are a boat builder so maybe my reservations are not relevant in your situation.
Good luck whatever you decide. I'm sure you can find the bracket build thread with a search and you will get plenty of help from the forum members.

[shine]

look forward to seeing the rebuild(s)

[flyingfrizzle]

You will be tough pressed to find much info on plans or measurements for a bracket build, not many do them and the ones that do it for a living its not in there interest to teach others how to build their own. Member BigShrimpin up here will be willing to help as I will as well. There are others that have built their own but very few.

When I build mine I match the transom angle of 13 degress to the back of the bracket outboard mount and run them parallel. The swim platform top is on the same plane as the boat deck or slightly elevated at the rear aft. The bottom I have done it two different ways, one matching the center panels at the same degree and one matching the bottom vee panels at 20 degrees. It will look better and gain better flotation if the bracket matches the panels and the boat vee. It mainly depends on how wide you make it to which panels you match. If you make the floatation tub the same width as the outer second panels I would match them. If you make it more narrow I would match the bottom panels like the hermco brackets do. I also built an 20 degree rake on my tub upwards to the rear of the outboard mount side so that as the water rises it will not act as a huge trim tab. This works out to be ruffly a 2" grade up to the rear of the bracket with a 2 foot set back. Doing this will allow you to mount it lower. Most metal brackets have this built in but the fiberglass ones I have seen look to be straight back with out a grade upwards. That may cause you to mount it higher to clear the water passing by it on plane. You loose some volume with the grade but then you gain it back by lowering the mounting height so it will yield more floatation volume back. The volume value between the two styles may not yield much more lift but I like the better looks of the tapered tub and feel like it has less water drag. Setback need at least 24" with most being around 30" or more to allow the motor to go to full tilt. Biggest thing when setting it up to look at is (1) motor height (2) swim platform height & height mounted to the boat (3) How high from the bottom of the hull you will mount it. (4) setback for motor tilt. I start with those 4 factors and then figure the dimensions in between to get the over all height, tub height, tub depth, motor mount ear height, and the angles of the transom and the angle of water rise (about 1.25" for 12" of setback) to determine the other angles that are not matching the hull bottom. Width is a preference but you can gain floatation value to a point then after that it max out then more just adds weight and no lift value.

On post #55 of the thread below there is a sheet on the last picture of some basic dimensions, but these are for a 25' hull. I have the dimensions for a 20' hull bracket that was on the 20' you saw the other week. I can send you those measurements via PM, just sent them to another member a few weeks ago. The 20 bracket I have will mount up around 2.5-3" from hull bottom for maximum floation and put the swim platform up about 2" above the water line while still giving you the correct motor mount height to get the outboard av fin in clean water while running.

http://www.classicseacraft.com/commu...t=26635&page=2

Like said I will try to sketch a ruff drawing of mine on my 20' hull and give you the basic dimensions and you can modify it to you likings. Seems like most people with brackets raise their motor high as possible and run out of adjustment before they get the outboard high enough. You will need about 4-4.5" of distance from the keel to the av plate depending on setback. Give your self enough tab to mount the outboard high enough to achieve this but at the same time watch out cause if you keep the swim platform close to the water height you will find out that your lower motor mounting bolt holes to be so high they end up needing to be drilled about where the foam or wood in the swim platform is. Mine are all the way as tight up as possible to the bottom of the platform and just barely work out getting the motor height right around the last holes of adjustment. I think mine are one hole down form the highest setting. To get any higher the platform would need to be raised and then you get it so far above the water line it is not as useful getting in the boat out of the water. It don't look as good high either. Also seal the lower bolt holes well or you will get water leaking into the tub from your lower mounting holes.

[TomParis]

If you look at the photos on Hermco's website they show installation of the bracket on the back of a 20 Seacraft.

http://www.hermco.com/gallery/nggallery/all/20-seacraft

According to their site the cost is 2500.00, which considering all things isnt too bad compared to spending 1k and your hours and hours of time involved.

[cbboatworks]

Mike thanks for your post and the info you shared I will take a look at that thread a little later, I just got home from a long day of working on the 65' Post and now headed to the shop for a night of grinding on the two 20's, everyday I ask myself the same thing over and over why in the hell do I torture myself with fiberglass and the need to do another restore

[cbboatworks]

I guess I should have shared a little bit about my background, and shared a little more in detail of what I was looking for. I am in the boating industry and run a full time boat repair/fiberglass shop..i build molds all the time from live wells, console to leaning post I am not in the market of resale or building parts for mass resale...I am looking for some rough numbers that has worked for others...and I fully understand if no one wants to share that info if that is where there income comes from..as for the price to build one i buy drums of resin, bulk glass and all my other materials in bulk so i have all this on hand, thank all of you who has posted

[Bigshrimpin]

CB - I'm no expert, but I've built a few. I can say with all honesty that building them won't save you much on those 2 builds unless you KISS. Hermco Style brackets have some complex shapes and take way more time and effort to copy (I mean model your design after) . . . I did a simple one for my dad's seawolf to hold a 30" 225 EFI and it was a LOT simpler than trying to copy Hermco's style. It was an ugly duckling b/c it had to fit b/w the trim tabs, cover 32" of transom over old stainless marine bracket holes, and hold a 30" motor. This style is cheaper and quicker to build and there's not one stress crack after 5 years. Down the center is one giant stringer inside the tub.








Vs.

My Hermco Copies

[cbboatworks]

Bigshrimpin that bracket looks good! thanks for the info and sharing the pictures, you looking a job its a lot warmer here in wilmington

[flyingfrizzle]

Cbboatworks you have a PM